The ragfish, Icosteus aenigmaticus Lockington, 1880: a synthesis of historical and recent records from the North Pacific Ocean and the Bering Sea
George H. Allen
The ragfish, Icosteus aenigmaticus (Fig. 1), with its soft musculature and cartilaginous skeleton, has been aptly characterized as a “puzzling fish with soft bones” (Fitch and Lavenberg, 1968; Moyle and Cech, 1996). Although external morphology has been described, most details of internal morphology and details of life history of this cold, deepwater species remain enigmatic and puzzling to science.
[FIGURE 1 OMITTED]
Historically, ragfish have been collected sporadically from the Pacific Ocean continental shelf of North America beginning off southern California, extending northward to the Gulf of Alaska, along the Aleutian Islands, and then south to eastern central Japan. Commercial fisheries have taken ragfish from the surface waters of the North Pacific Ocean, the Gulf of Alaska, and the Bering Sea, in addition to relatively shallow coastal bays and inlets. Maximum depth of ragfish habitat off the continental shelf is unknown, as well as most factors of its life history. Only recently have detailed aspects of the species’ early life history (ELH) been published (Matarese et al., 1984, 1989; Wing and Kamikawa, 1995; Wing et al., 1997). No specific study on the biology of adults, however, has been reported in the literature, except a preliminary note on fecundity (Allen, 1968).
There have been, and still are, difficulties with the taxonomy and classifcation of the species. Early ragfish descriptions and taxonomy were unaware of the changes in morphology from juvenile to adult stage. Clemens and Wilby (1961: 236), in combining juvenile and adult forms in the same species, summarized these changes as follows:
“… the pelvic fins, which are
loosely attached in the young,
become lost; the limp skin encroaches
more and more over the
anterior ends of the dorsal and anal
fins thus giving a low count of the
rays except under dissection; the
modified scales disappear; the character
of the pectoral and caudal fins
is changed from round to pointed
in the former, and from round to
broadly emarginate in the latter;
the yellow color and purplish spots
change to a more somber brown as
the adults attain greater size.”
Not surprisingly, Lockington (1880), in his initial description of the species, named juveniles as “spotted ragfish,” Icosteus aenigmaticus, while Bean (1887) called the first adult he described the “brown” ragfish, Acrotus willoughbyi. Goode and Bean (1895) used the common name of “fantail ragfish” as did many subsequent authors (Regan, 1923; Clemens and Wilby, 1949; Kamohara, 1962; Abe, 1963). Some reports omitted a common name, while others used the generic ragfish or “rag” fish (Higgins, 1921; Thompson, 1921). Crawford (1927) applied ragfish to an adult specimen, while Prichard (1929) applied the term to a juvenile, suggesting that the adult and juveniles were being considered as the same species. Barnhart (1936) bucked the unifying trend by using “speckled ragfish” for the juvenile and “giant ragfish” for the adult. Schultz (1936), however, employed the common name ragfish to both juveniles and adults at the species level, but he used “ragfishes” for the family Icosteidae (juveniles) and “pelagic fish” for the family Acrotidae (adults).
Following a hiatus in general scientific work associated with World War II, Fitch (1953) used “ragfish” in reporting on both juveniles and adults, as did Wilimovsky (1954). No mention was made of English common names when Japanese authors began reporting in English on ragfish juveniles recovered off Japan (Abe, 1954). Kobayashi and Ueno (1956) omitted any English common name but did note that the caudal fin as “very broad and fan-like,” with a pictured specimen (69 cm TL) of an adult showing the tail slightly emarginate. Kamohara (1962:5) listed only the Japanese common name for a described ragfish but also reported on the tail “… the peduncle widening posteriorly to support the fan-shaped caudal.” The common name of ragfish “became applied consistently when the juvenile and adult stages were recognized as the same species (Bailey et al., 1960; Clemens and Wilby, 1961).
Fishermen commonly contribute a plethora of common names for fish they catch, but when rarely encountered species are caught, the common name applied by taxonomists, if known, usually suffices. For the ragfish an exception may have been whalers apparently using their own unique common name (Cowan, 1938:97): “Dr. Robbins is confident that the ‘bastard halibut’ of the whalers is identical with the brown ragfish.” I feel it likely that the general public tends to consider beached large female ragfish as some sort of Pacific salmon.
Gross external morphology and coloration differences between adult ragfish (Fig. 2A-E) and juvenile ragfish also influenced the history of taxonomic studies of the species. Gunther (1887:46), after reviewing the literature and examining two juveniles in his collection, named the species Schedophilus enigmaticus Steindachner, even though Steindachner, in an 1881 paper, used Icosteus enigmaticus. Gunther placed ragfishes in the family Coryphaenidae, stating that he had failed to find in published descriptions anything that would warrant a generic separation from Schedophilus or the creation of a distinct family “Icosteidae.” Lockington (1880) also puzzled over taxonomic status when he listed the ragfish in the family Blennidae. Bean (1887) noted that the adult ragfish he described appeared to be closely related to Icosteus, but he did not specifically designate a family.
Reflecting the early tentative taxonomies, Dean et al. (1923:646) listed four kinds of “ragfishes” under the family Icosteidae (Acrotus, Icicthys, Icosteus, and Schedophilius medusophagaus). Both juveniles and adults were combined under one species (Acrotus willoughbyi Bean) and family Acrotidae (Ulrey and Greeley, 1928). The “rule of priority,” however, assigns the name to Lockington with “ragfish” the official common name, the genus Icosteus, and family Icosteidae (Wilimovsky, 1954; Fitch and Lavenberg, 1968; Miller and Lea, 1972; Hart, 1973; Wheeler, 1975; Nelson, 1976; Matarese et al., 1984; Moyle and Cech, 1996).
There also has been difficulty in assignment of the family to higher taxa due to a continued puzzlement over ragfish evolutionary history. Thus Regan (1923: 612) wrote: “The exact systematic position of the Icosteidae is uncertain, but the great development of cartilage and the weakness of the bones is evidently secondary, and there is nothing in their organization to prevent the assumption that the Icosteidae represent a specialized and somewhat degenerate development of the Perciform type.” Berg (1940:494) accepted Regan’s opinion, and placed the family Icosteidae in a separate order Icosteiformes (Malacichthyes). Matarese et al. (1984), in their study of larval forms up to 2.8 cm in length, identified both blennoid and stromatoid morphological features. They summarized the present ragfish status as follows: “The systematic position of this group and its designation as an order or suborder is not well established. Greenwood et al. (1966) considered it a suborder of Perciformes (Icosteoidae) while Gosline (1973) elevated it to an order, Icosteiformes, a probable perciform derivative” (Matarese et al., 1984:576).
A black-and-white drawing of excellent quality of an early 26 cm long juvenile showing external morphology and the pattern and texture of the skin was published in Gunther (1887:46, Plate XLIV, Schedophilus enigmaticus). Goode and Bean (1895) conveniently placed line drawings of a juvenile and an adult together (Plate LXII), and included illustrations of other species with close affinities (Icicthys lockington, Centrolophus pompilus, Schedophilus medusophagus) (Plates LXI, LXII). Recent photographs of a juvenile appeared in Fitch (1953) and Fitch and Lavenberg (1968). Illustrations of adults were published by Jordan and Evermarm (1898:973) and Clemens and Wilby (1961:333). A color illustration of an adult can be found in Eschmeyer and Herald (1983:Plate 46). The most appealing historical photograph of an adult ragfish is that of the Yecny family arranged beside a suspended 152 cm (5 ft) specimen caught while sport fishing on 20 May 1940 from a breakwater at Monterey Bay, Calif. (Bolin, 1940:287). The most accurate depiction of the general shape and skin pattern of juvenile and adult ragfish is that in Hart (1973:386). Such general shape and skin patterns are evident in photographs of juvenile and adult specimens that only came to my attention during March 2002 (Fig. 3A, B).
[FIGURES 2-3 OMITTED]
Prior to August 1999, I had assembled over 200 unpublished and published historical records on ragfish, with some historical records added in December 1999 and February 2000. During August 1999, I received from J. Heifetz (1) data on 620 ragfish specimens incidentally observed and recorded during studies on commercially important species taken by U.S. fishermen from California to the Bering Sea. These records from the NMFS Alaska Fisheries Science Center, Seattle, Wash., and records of ragfish existing in published literature, were primarily used to enlarge our knowledge of ragfish distribution, both geographically and ecologically. Much new biology and life history aspects of the ragfish came principally from the records of specimens taken by bottom trawlers operating off northern California and southern Oregon and by the California Department ofFish and Game (CDFG), Oregon Department of Fish and Wildlife (ODFW), and by the fisheries department at Humboldt State University (HSU), Areata, Calif.
Materials and Methods
Historically, ragfish have come to science through fishermen and citizens who retain specimens and voluntarily deliver them to fisheries management personnel, museum curators, and ichthyologists. My first experience with ragfish was in this tradition when, in 1958, a crew member of a commercial bottom trawler (F/V Sitka) operating out of Eureka, Calif., prevented the discard at sea of a single large female ragfish. The crew member, a personal acquaintance, phoned me from the dock to come and examine the fish. I observed a running-ripe female that subsequently became one of the four females in a preliminary study of ragfish fecundity (Allen, 1968).
From 1958 through 1989, a total of 39 fresh specimens taken by commercial trawlers landing catches mainly at Fort Bragg, Eureka, and Crescent City, Calif., were transferred to HSU for study along with another 44 specimens from northern California and southern Oregon, recorded and catalogued by the CDFG (Table 1). A mail survey in 1977 of 14 museums and agencies (excluding CDFG) with known fish collections produced 67 historical records. In 1998 and 1999 state and Federal fisheries biologists in Juneau and Petersburg, Alaska, forwarded 16 more ragfish records. Additional records of California ragfish recovered in 2000 were not incorporated into this report due to my desire to bring the report to a conclusion. Historical records were mainly of larger juveniles and mature females (Table 2).
Other important sources of ragfish data were found in published and institutional archival reports by governmental agencies engaged in monitoring and research associated with the management of North Pacific Ocean fisheries. One of the longest and most detailed of these studies was on early life history (ELH) stages (eggs and larvae) of commercially important marine fish species sampled from 1951 to 1984 by the California Cooperative Fisheries Investigation (CalCOFI). The sampling grid overlays three coastal zoogeographic provinces, a coastal upwelling zone, and three oceanic water masses of the eastern North Pacific (Moser et al., 1993; Moser et al., 1994). Other recent records of ELH stages of ragfish are those from the eastern North Pacific Ocean where specimens were sampled during studies on commercial groundfish stocks of the continental shelf from Sitka to Dixon Entrance (Wing and Kamikawa, 1995; Wing et al., 1997). An international effort during the 1990-91 fishing seasons to document incidental catches of fish, mammals, and birds of conservation concern in major North Pacific commercial surface gillnet fisheries for squid and salmon also recorded ragfish (INPFC). (2) Reports on three national fisheries listed 27 records of ragfish taken from generalized areas (Japan: McKinnell et al. (3); China: Yeh et al. (4); Korea: Park et al. (5)). No other data were included since the studies focused on the incidental catch of animals of international conservation concern.
Analysis of Historical Data
Most fresh adult ragfish delivered to HSU were measured (cm) for total length (TL) and standard length (SL), and for total and gonad weight (gm). Data on depth, location, and time of capture were furnished either by the person capturing the specimens or by CDFC biologists who examined the ragfish on the docks. Most useful data on 66 specimens >35 cm came from seven institutions (HSU, 34; CDFG, 15; CAS, 8; ABL, 3; BCPM, 3; UBC, 2; MLML, 1). (6) Smaller specimens (<35 cm SL) recorded in museum collections were immature juveniles, with available records containing only scant biological data. Data on juveniles were used primarily in studying distribution. CDFG ragfish records supplied by John Fitch (7) were for fish landed mainly south of Cape Mendocino, and measurements were similar to those taken on HSU specimens. Miscellaneous observations on some fish in HSU and CDFG included notes on stomach contents, whether eggs were running from the vent, and a few had measurements on length and weight of ovaries.
Metrics for larger ragfish were computed by D. Hankin and HSU fisheries students. (8) Specimens measured (cm) for TL only in the field were converted to SL by the equation: SL = 2.57 + 0.87 TL (R = 0.98, n = 41) (Osborn (8)). Specimens without weights were estimated by least-squares regression (Zar, 1984) using males and females combined (Wt = 6.27g; SL = 2.7cm; R = 0.98, n = 30) (Bremm (8)). For fecundity studies, missing weights of large females used only females. Equations describing fecundity, egg maturation, and relative size of gonads are presented in results.
Written comments on whether eggs were flowing freely from the vent of adult female were not specifically recorded for some female specimens collected by HSU and CDFG. These records probably indicated no running ripe eggs. Some specimens were damaged in transit to HSU, and a few ovaries were ruptured or damaged during examinations made prior to delivery to HSU. For a few females, the ovaries were the only part of the fish deposited at HSU. Sufficient data were available on 14 females delivered to HSU to enlarge the estimates of fecundity. Standard gravimetric methods as described in Allen (1968) were used in estimating egg numbers. In a preliminary study, from 5 to 27 aliquot samples of eggs, depending upon the size of the ovary, were taken from predetermined positions along both ovaries. Three categories of egg size were noted in most ovaries. A study of the mean diameter of the “large-category” eggs (1.0-3.0 mm) in two specimens (HSU 7, 9) found no difference in aliquots taken from 19 to 25 positions along the length of the ovary. This confirmed a preliminary study that eggs were maturing at equal rates in all portions of the ovary (Alien, 1968). Subsequently aliquots were sampled from 5 to 9 positions only.
The gonads of one specimen (HSU No. 25, total gonad length 31.5 cm), appearing peculiar in gross external morphology, were studied histologically. The external formalized most-anterior section of the ovary was creamy white in appearance, a middle section purplish in color with some whitish underlying patches, and a posterior section was grayish in color with some purple tinge. A final narrow section of the gonad attaching to the vent presented a much more granular texture than the rest of the gonad. Gonad fixation was in 10% Formalin, dehydration and embedding used a tertiary butyl alcohol series, with staining by hematoxylin and eosin. Transverse sections 10 mm thick of tissue sampled from left and right positions along the length of the gonad were studied for any histological changes that might have indicated incipient hermaphrodism in the specimen.
Ragfish Capture Gear
Many types of fishing gear have taken ragfish in the historic record. Not only is this information inherently interesting, but it can be of practical value when planning future ragfish studies. Knowing which depths and bottom substrates have been sampled by various gear can direct future research toward unsampled areas (Allen et al., 1961).
The most unique acquisitions of ragfish arise from hand collections involving chance encounters with moribund or dead ragfish either washed up on beaches or stranded in adjacent shallow waters. Ragfishes used by ichthyologists initially describing the species were all from chance hand collections (Lockington, 1880: 3 specimens found on a fishmonger’s display table in San Francisco in 1885; Bean, 1887: an adult from a beach at Damon, Wash., collected by Charles Willoughy, Indian agent). Another early specimen was hand collected by J. O. Snyder in 1906 from a beach at Pacific Grove, Calif. (6 cm fish, USNM 75159). Craig Carrothers, an HSU student, found a 9 cm SL juvenile in shallow water at the foot of a boat ramp located north of the north jetty entrance to Humboldt Bay, Calif. (9) A surprisingly large number of adults have been hand collected from the beaches of bays and inlets of southeastern Alaska (6 records furnished by Bracken (10) and Wing (11)). Other recoveries from beaches in southeastern Alaska were made by school children on field trips and by young boys on fishing trips near Kake and Petersburg, Alaska (Marsh, 1995; Kondro (12)). Marsh reproduced in his magazine article a photograph of one of these specimens being displayed by its captors.
Probably the most interesting example of a hand collection was that of a specimen taken from a Steller sea lion, Eumetopias jubata, in surface water by a sport fisherman at Outer Point near Auke Bay and about 3 mi. northwest of Juneau, Alaska, 9 May 2000 (Wing (13)). The fisherman was attracted by a surface disturbance caused by the sea lion and was able to collect the posterior trunk and tail of the ragfish. The remains (= 150 cm TL) were given to K Koski for delivery to ABL for identification.
Many different trawls have taken ragfish: commercial bottom (otter) trawls, shrimp trawls of several designs, beam trawls, and midwater trawls. Historically, the largest number of ragfish records have come from adults taken by otter trawls used in a commercial fishery on the continental shelf between Camp Mendocino and Pt. St. George, northern California. Bracken (10) and Wing (13) recorded ragfish captures from inside waters of southeastern Alaska by both shrimp and beam trawls. A modified North Atlantic capelin net took an adult ragfish (130 cm) when fishing at 75 fm (137 m) over a bottom depth of about 300 fm (549 m) in the lower end of Chatham Strait, southeastern Alaska, in late June 1976 (Bracken (l0)). Midwater trawling by Canadian researchers has incidentally taken ragfish (Peden, 1974). Two adults (80 and 90 cm, BCPM 972-62) came from a station 70-80 mi. west of Cape Flattery, Wash., while a third fish (BCPM 80-120, size unknown) was caught near the Cobb Seamount off Washington’s northwest coast.
The commercial bottom and pelagic trawl fisheries off the west coast of the United States, contributing most of the ragfish documented in the historic records, also were the source of many ragfish recorded in the NMFS observer program (Table 3, geographic Area B). It was not feasible to describe all the types of trawls used in these fisheries. NMFS research surveys of these same fisheries took many ragfish primarily using bottom trawls fished both in the water column and near the ocean bottom.
The earliest gillnet caught ragfish were recorded from southern California (Fitch and Lavenberg, 1968). Wing (11) recorded four gillnet caught ragfish from southeastern Alaska waters. Canadian research studies associated with the North Pacific salmon fisheries took nine ragfish in gillnets (Larkins, 1964). A. E. Peden (14) listed a juvenile fish taken in a surface gillnet on 28 August 1970, 85 mi. northeast of Attu Island in the Bering Sea. As noted earlier, at least 27 ragfish were identified while sampling the high-seas commercial catches of salmon gillnet fisheries in 1990 under international monitoring programs, as detailed later in section on ragfish distribution in the North Pacifc Ocean.
Seines operated from vessels or fished from beaches have also caught ragfish. Higgins (1921) noted a specimen of ragfish as being taken in a “mackerel net” off San Pedro, Calif., presumably a seine of some sort. A purse seine set near Weaver Bay, Queen Charlotte Islands, B.C., took a juvenile ragfish (Pritchard, 1929) which probably was the specimen used to illustrate a juvenile pictured in Clemens and Wilby (1961:Fig. 248). If the “commercial salmon seine” that Schultz (1930) reported to have taken a ragfish (size not available) (near the mouth of the Columbia River at Ilwaco 12 August 1926), actually was a beach seine operated from shore, this would be another type of sampling gear taking ragfish. Purse seine fisheries off central and southern California have taken “fair numbers” of ragfish (Fitch and Lavenberg, 1968), probably as associated with the large historical fishing effort for sardines (e.g. one specimen recorded in 1927: HMCZ 34915). In July 1962, a purse seine captured a juvenile ragfish (27 cm SL) 25 n.mi. northeast east of San Clemente Island, southern California (SIO 062-385). Wing (11) reported a unique catch of a ragfish in shallow water (7 m) with a commercial purse seine fishing for salmon in Amalga Harbor located 24 mi. north of Juneau, Alaska, at the head of Chatham Strait. The specimen was estimated to be about “six-feet (183 cm) long” and was stored for future study.
Whale and Fish Stomachs
Clemens and Wilby (1949) noted several authors reporting sperm whale, Physeter catodon, stomachs as a source of ragfish specimens; with the 1937 record of a ragfish head from a sperm whale taken 30-50 n.mi. northwest of Rose Harbor, Queen Charlotte Islands, B.C. (FMNH 35,590) most frequently cited. Fish stomachs also provide ragfish records, such as the 16 cm SL specimen found in a tuna (species and length unspecified) taken in June 1970, 85 mi. northwest of the Columbia River mouth (Stein (15)).
Stationary fixed gear such as traps have also taken ragfish. Movable box-shaped traps used for sablefish, Anoplopoma fimbria Pallas, caught ragfish (specimen size and sex not listed) in Barkley Sound, B.C. from 265 fm (485 m) depth (Cowan, 1938). Stationary traps with a panel (lead) attached to shore used in early commercial salmon fisheries have also taken ragfish. Crawford (1927) lists a female about 6 ft long (183 cm) caught at Whidby Island, Wash. on 15 September 1925, as well as noting another ragfish reported from a trap operated at Gig Harbor, Wash., in 1913 or 1914. The largest recorded specimen (208 cm TL) found in the literature came from a stationary salmon trap at Sooke, B.C. (Cowan, 1938). The first records in English known to the author of ragfish off the Pacific coast of Japan were from trap catches (Abe, 1954, 1963).
Hook and Line
Hook-and-line gear used by anglers have regularly sampled ragfish from shallow waters along the west coast of North America. An adult taken from a breakwater at Monterey Bay, Calif., was previously mentioned (Bolin, 1940). Two small boys fishing from a breakwater at Victoria, B.C., in July 1936, took an adult that appeared to be larger than the biggest ragfish yet officially recorded (208 cm TL) (Cowan, 1938). A 25 cm SL ragfish (UCLA W-53-245) was caught by hook and line fishing from a boat on 17 May 1953, in shallow water off San Onofre, Calif. (Fitch, 1953). Fishery biologist D. Bevan took a juvenile ragfish while fishing in 110 fm (201 m) 8.5 n.mi. south southwest of Kruzof Island, Alaska, on 13 Sept. 1958.
Gear Not Represented
From a technical fish sampling viewpoint, I found it surprising that there were no records of ragfish taken by salmon trolling gear in northern California waters. D. Bitts (16), a troll fisherman, could not recall that he or other trollers ever caught a ragfish. Similarly, no records in the literature were found of ragfish being caught on longline fishing gear used for Pacific halibut, Hippoglossus stenolepis Schmidt, or sablefish. Future reviews of research and management agency files on troll and longline fisheries should be made, since these gears fish areas not readily sampled by other gear types (rocky reefs and headlands).
A history of ragfish range extensions is presented geographically beginning in California and proceeding counterclockwise around the North Pacific. This analysis primarily uses historical literature and is supplemented where appropriate with records from previously mentioned NMFS databases.
On average, about one specimen per year has been recorded historically by ichthyologists over the past 125 years from ragfish caught in the eastern North Pacific Ocean (Fig. 4B). Bolin (1940: 287) commented on the early accession rate of ragfish as follows: “This rare visitor, which on the basis of meager available records appears to be taken about once every 20 years from the waters of the state, is stated by Schultz and DeLacy (1936) to be not rare in the Pacific Northwest although I have been able to find only eleven definite records of its previous capture.” Schultz and DeLacy’s contention proved correct. The rate of accession of ragfish specimens increased dramatically after the end of World War II (Fig. 4B).
[FIGURE 4 OMITTED]
The southern end of the now known ragfish range provided the juvenile specimens taken off San Francisco that were used for the species’ original description (Lockington, 1880). Range extensions that were recorded from 1875 to the turn of the 20th century, as reported by Jordan and Everman (1898), came from the capture of ten additional juveniles (about 25 cm length) that were known from “Deep water off California, Oregon, and Washington; the example before us from Monterey” (Fig. 4C). Southward extensions of the range extended to San Pedro (Higgins, 1921), to Monterey (Thompson, 1921), to Cortes Bank 100 n.mi. off San Diego (Fitch, 1953), and of larval ragfish to lat. 30.5[degrees]N off northern Baja California, Mexico (Moser et al., 1994). Northward extensions were reported by Schultz (1930) to the mouth of the Columbia River; by Pritchard (1929) to inside waters of the Queen Charlotte Island, B.C., Canada; by Schultz et al. (1932) to inside waters near Petersburg, Alaska; by Schultz and DeLacy (1935-36) to southern Puget Sound; and by Cowan (1938) to the Strait of Juan de Fuca.
NMFS catch records came from two separate programs that studied U.S. commercial fisheries extending from the Bering Sea to southern California (Table 3). The Commercial Fishery Observer program of the NMFS Alaska Fisheries Science Center, Seattle, Wash., placed personnel on commercial fishing vessels beginning in 1987 to sample the catch of walleye pollock, Theragra chalcogramma (Resource Ecology and Fisheries Management program (REFM)). The first ragfish reported by an observer in 1987 was caught by a bottom trawl fished southwest of the entrance to Yakutat Bay, Gulf of Alaska, off the edge of the continental shelf at 192 m (105 fm). From 1987 to mid 1999, the observer program logged 529 ragfish. A second program by the NMFS that has recorded ragfish catches was a scientific survey of bottom fishes conducted by trawling (Resource Management and Conservation Engineering (RACE)). Two ragfish were logged in 1976 from bottom trawls conducted off central California, with the last ragfish reported caught in 1998. Survey trawling recovered 91 ragfish total. Only 18 ragfish recorded in the two studies were taken from California waters (Table 3, geographic area C).
Inconsistency and incompleteness of information available on adult ragfish, other than the CDFG and HSU collections, circumscribed the analysis that could be performed with the data. Degree of completeness of the ragfish data was defined by the presence of six desired metrics: 1) date: often only the year of capture was listed; 2) location: often only a general geographic area of recovery was listed; 3) depth of water where fish were recovered: precise depths could be estimated when latitude and longitude at the beginning and ending of hauls were given, but often records only listed a single depth; 4) length: often not standardized; 5) weight: mostly in pounds; and 6) sex: often reported with equivocation. For 52 specimens in the HSU and CDFG records, the percentages of completeness within the six categories were: 98, 49, 70, 85, 42, and 63, respectively. Least complete were location of capture (49% complete) and weight (42% complete). For individual specimens, only 21% had data on all six categories, while 14% of the specimens had only data on three or fewer of the categories. Data on ragfish accessed from institutions other than HSU or CDFG were much less complete. This varied from 4% of the specimens having only information listed for only one of the six categories, to only 4% with information on five or six categories. Consequently, data on ragfish recorded by CDFG and HSU was most useful for biological studies, with the remaining data mainly utilized for subjective studies of distribution and historical occurrences.
The commercial fishery observers (REFM) listed date of trawl, trawl number, year, gear (mostly pelagic trawl with a few bottom trawls listed), latitude and longitude of the trawl location, depth in meters at which the gear was fished, and the depth of the ocean floor at the trawl location. NMFS scientific surveys (RACE) employed bottom trawls as their standard sampling gear, with some hauls also made off the bottom. Of the 91 specimens listed, 83 were weighed (kg), and 5 specimens were measured for length (mm). Surface water temperatures at trawl locations were listed for most hauls, while for 52 hauls the temperature was recorded at the depth at which the gear was fished. Most hauls in the RACE data bank showed a single specimen for each trawl, but 11 hauls listed from 2 to 6 ragfish in the catch. Total weight only was listed for ragfish observed in each haul, thus only mean weight could be reported for hauls listing more than a single ragfish.
Range extensions into the western and central North Pacific Ocean came from specimens found by fisheries agencies during increased monitoring and research of commercial fisheries. Off Japan, Abe (1954) described the first record of a ragfish (a 26 cm juvenile), followed by an extension of ragfishes to roughly 400 n.mi. east-southeast of the southern tip of the Kamtchatka Peninsula by a recovery of 7 specimens (48-75 cm) from a Japanese high-seas gillnet fishery (Kobayashi and Ueno, 1956).
Range extensions also occurred into the eastern North Pacific from an incidental catch of nine ragfish by U.S. Bureau of Fisheries research vessels from 1955 to 1961 (Larkins, 1964). The ragfish came from widely scattered points (southern Bering Sea, North Pacific Ocean bordering the Aleutian Islands, and in northern and southern portions of the Gulf of Alaska). No catches came from the northern portions of the Bering Sea or in the eastern North Pacific Ocean south of lat. 50[degrees]N.
The first eastern North Pacific Ocean specimens were found by research trawling 72 n.mi. due west of Cape Flattery, Wash. (Peden, 1974). More recent incidental catches of ragfish in commercial high-seas salmon fisheries were reported in 1991 and 1992. These records came from western North Pacific Japanese, Korean, and Taiwanese gillnet fisheries for salmon and squid that were being monitored owing to concern about incidental catches of marine mammals, seabirds, and marine turtles (McKinnell et al. (3), Yeh et al. (4), Park et al. (5)). These reports listed ragfish as “unidentified ragfish/medusafish,” ragfish only, or separately as ragfish and medusafish, Icichthys lockingtoni. On first glance, medusafish superficially appear like juvenile ragfish (Goode and Beane, 1895, Plates LXI, LXII), and thus would be a source of confusion among partially trained personnel sampling the catches of the commercial fishing vessels.
Months of recoveries in these 1990-91 high-seas fisheries were: March-Japanese, 4 unidentified ragfish/medusafish; September-Korean, 8 ragfish and 50 medusafish; and no month-Taiwanese, 15 ragfish. The most southerly operations of these fleets were Japanese, lat. 26[degrees]N, long. 180[degrees]; Korean, lat. 40[degrees]N, long. 178[degrees]W; and Taiwanese, lat. 35[degrees]N, long. 178[degrees]W. Field notes and voucher photographs of specimens could not be consulted for this paper to precisely locate the most southerly point of recoveries. I suggest, however, that in the future, ragfish might be found as far south as the Kinmei Seamount (lat. 35[degree]N, long. 172[degree]E) which rises to about 20 fm (37 m) below the ocean surface.
Knowledge of ragfish distribution in the North Pacific Ocean was dramatically expanded with the recovery of specimens associated with the monitoring of commercial fisheries in the eastern Pacific Ocean and the Bering Sea by NMFS. Ragfish catch locations reported in the RACE and REFM programs ranged from Pt. Lopez, central California coast, to the central Bering Sea, with large numbers of ragfish reported caught just north of the central Aleutian Islands (Fig. 5). To reduce ragfish recovery patterns possibly biased by the commercial fishery concentrating on walleye pollock, the recoveries made by the research fishing (RACE) were plotted separately (Fig. 6). In both plots there is a striking pattern of recoveries roughly along the 100 fm contour separating Bristol Bay to the east from the deep waters of the Bering Sea to the west.
[FIGURES 5-6 OMITTED]
A pattern of recoveries beginning at Unimak Pass in the eastern Aleutian Islands stretching northwest along the 100 fm (200 m) contour ended in the north central Bering Sea just beyond lat. 60[degrees]N. The waters to the east of the 100 fm contour are relatively shallow (< 100 fm). To the west, however, the ocean floor drops steeply to over 1,000 fm (1,830 m). The most northward cluster of ragfish catches along this drop-off was beyond lat. 60[degrees]N and approaching long. 180[degrees]. Marine charts available to me indicated the possibility of a relic drainage depression providing a gentle transition from the very shallow water of the Bering Strait to the north and the deepwater basins of the Bering Sea to the south. This area of transition lies roughly 140 n.mi. southeast of Cape Navarin, Siberia, and about 150 n.mi. west of the south end of St. Matthews Island. The bottom is listed as primarily gray mud interspersed with a mixture of sand and shell. The gear depth listed for these northernmost trawls were shallow and virtually the same as listed for water depth (40-80 fm or 73-146 m range).
Precise analysis of the location and depth of all trawls in the NMFS data banks needs to be undertaken to expand this cursory use of the NMFS data to delineate ragfish distribution and habitats. Ragfish distribution records are lacking for the continental shelf off British Columbia, Can. This is probably due to the research surveys only sampling surface waters (Taylor, 1967a, b: 100 fm or 183 m). Canadian agencies managing commercial bottom trawl fisheries were not contacted for possible records in this study.
Early and Juvenile Life History
Ragfish early life history (ELH) stages for the eastern North Pacific Ocean have only been collected and described since the end of World War H when resources became available to study the ocean environment associated with major commercial fisheries in the California current (Matarese et al., 1984, 1989; Moser et al., 1993,1994). A distinctive external morphology was described for ragfish eggs by Watson (1996:1201) as follows: The “ragfish eggs are readily distinguished from all others by chorion and oil globule diameter, and in late stages by the embryonic pigmentation” (Fig. 7).
[FIGURE 7 OMITTED]
Eggs and larvae of ragfish off California were in low abundance throughout the range of the sampling program, with the greatest density (mean number for all tows of 0.10-0.13 eggs/10 [m.sup.2] lying between San Francisco Bay and Point Conception (Moser et al., 1994: 86). Most ragfish eggs and juveniles in this area were taken in March and were concentrated at two distinct distances offshore (10–20 and 50–200 n.mi.) (Fig. 8) (Moser et al., 1994:86). Sampling was relatively sparse in northern California waters.
[FIGURE 8 OMITTED]
An extensive study in May 1990 of early life history of marine fishes in the eastern North Pacific Ocean off southeastern Alaska was conducted by the NMFS (Wing and Kamikawa, 1995; Wing et al., 1997). The area surveyed was covered by eight transects ranging from lat. 58[degrees]N, long. 140[degrees]W southeastward to lat. 54[degrees]30N, long. 136[degrees]W (Cross Sound to Dixon Entrance) and varied from about 200 n.mi. by 100 n.mi. in width. Neuston was sampled using 50 x 30 cm Sameoto neuston net equipped with a 0.505 mm mesh net and a plastic cod end. A total of 86 tows, each 1 n.mi. in distance, sampled the top 51 cm of the water column at 67 stations.
No ragfish larvae were noted in the catches, although, at the 56 stations where fish eggs were recovered, ragfish eggs were third most abundant. Very few ragfish eggs occurred in tows made inside the 200 m (37 fm) depth contour, except for a station located at the southern entrance to Chatham Strait (Wing et al., 1997:Sta. 4a, Fig. 1, 4). The study also sampled the water column for ichthyoplankton by oblique tows with a 60 cm diameter bongo net array fitted with two 505 mm mesh nets and cod ends. Maximum sampling depth targeted was 300 m but varied according to bottom depth and contour over shallower waters. Ragfish eggs were the second most abundant fish eggs collected (Wing et al., 1997: Table 3). Surprisingly, no ragfish larvae were identified among the 100 taxa and suspected species listed from these same samples (Wing et al., 1997: Tables 2, 3). Most of the ragfish eggs were found in tows made beyond the 200 m (100 fm) contour, and they were most abundant in the southern half of the study area (entrance to Chatham Strait to the north edge of Dixon Entrance).
Central California and southeastern Alaska ragfish eggs and larvae have some similarities in their local distribution patterns. Eggs and larvae were scarce to absent in shallow nearshore waters. The overall abundance within each study was near or adjacent to submarine canyons (Monterey Canyon, Calif.), and in the deeper waters of the entrances to large inlets and bays (southeastern Alaska). Also, the sampling gear in both areas failed to take larger larvae (roughly >3 cm TL).
Several authors have commented on the lack of knowledge on ragfish between the ELH stages in the sampling and the subsequent appearance of larger juveniles (Matarese et al., 1984). Historical records provided little data on ragfish ranging between 5 and 50 cm range (Fig. 9). Depth of capture of smaller specimens was uncertain or rarely recorded (unknown: 6, 7, 16, 20, 20, 28, 38, 52 cm; shallow, 1 fish 25 fm and 1 fish 50–450 fm). Smaller juveniles had a slight tendency to be caught nearer to shore than larger juveniles (Table 4), with catch locations varying between the surf zone and 14 n.mi. off the coast. Smaller ragfish reported in other regions around the North Pacific Ocean include a juvenile of unknown length taken in a surface gill net 85 n.mi. northeast of Attu Island in the Bering Sea, and a 38 cm fish from the Gulf of Alaska about 200 n.mi. southwest of the entrance to Cross Sound (ABL: AB 61-38; lat. 57[degrees]N, long. 141[degrees]W), and a 48 cm specimen (UW 8385) from the north Pacific (no specific location). The last ragfish to enter the HSU records was a small spotted juvenile estimated at 33 cm (13 in) length by a fisherman who did not wish to donate the specimen because it held aesthetic appeal to him. The fish was captured on 3 August 1999 in one of three midwater trawls made at 100-135 fm (183-247 m) depths while fishing on a north to south track over the 500 fm (915 m) contour about 15 n.mi. west of Redding Rock off northern California. Historically, there were two other juveniles, one of 19 cm, also recorded from this area (Table 4).
Of 53 ragfish reported off the central and northern coasts of Japan (Kubota and Uyeno, 1971: Tables 1, 2) most were juveniles between 25 and 33 cm SL, except the smallest specimen of 15 cm SL taken by a trap net set for Seriola sp. and Trachurus sp. off Manazura, Sagami Bay, central Japan (Abe, 1954). Most of these specimens were in or destined for the fish markets and were caught relatively close to shore where deep water occurred. The shallow nearshore place of capture of the 31 cm SL juvenile in Figure 3A is consistent with conditions of capture for other California juveniles recorded, and especially with the catch location of Japanese juvenile ragfish.
Smaller juveniles (5-20 cm TL) were taken in a program of studying ichthyoplankton off Oregon conducted over a 20-year period by Oregon State University’s Department of Oceanography (Table 5). Collections were made with midwater trawls fished obliquely or through surface waters. There were 21 juvenile ragfish caught ranging from 1.5 to 16.5 cm TL (Table 5). Ragfish juveniles were sampled primarily from surface waters extending 19-85 n.mi. off the coast. In 7 tows the nets were fished only from 50 fm (92 m) to the surface, in 2 hauls the nets were sampled in a 100-150 fm (183-274 m) range, and two other samplings began at a 500-600 fm (942-1,098 m) range. Even though there is uncertainty from having specimens caught at any depth during lowering and retrieving the trawls, the small, immature ragfish appeared to be distributed randomly throughout the sampled area.
Of the 22 smaller ragfish (<1.1 kg) from continental shelf research reported in the NMFS (RACE) database (Table 6), most only had weight listed, with only 7 specimens also measured for length (cm). Of these, 5 were juveniles taken off the coasts of Oregon and Washington (Fig. 10), at depths of capture comparable to that found for all smaller ragfish recorded in the database (Fig. 11). Although the smaller ragfish (<0.1 kg) were in the shallowest water (<150 fm or 274 m), slightly larger ragfish (0.3-0.5 kg) were found over all depths occupied by larger ragfish recorded from all areas and seasons (Table 7). These data all suggest that the transformation of small juveniles into larger immature fish occurs at about the same time that the pelvic fins are being reduced (Komori, 1993:30-36 cm). These smaller immature ragfish occurred in a range of depth and location comparable to those found for the larger adults. Over the extensive range of the ragfish, however, there continues a general paucity of data on ragfish life history between ELH stages and appearance of smaller juveniles noted by Matarese et al. (1984).
Early records could not establish sex ratios because immature juvenile ragfish dominated the samples available to taxonomists initially describing the species (Lockington, 1880). Subsequently, only a few mature females (Bean, 1887) appeared in the historical record, and this imbalance continued to modern times (Tables l, 2). Historically, although, some males were reported, authors noted difficulty in assigning sex to specimens with developing gonads. For example, a 136 cm ragfish was caught 18 July 1935 by a fisherman in the proximity of Sooke Harbour, B.C. (BCPM 1935-1), for which the curator was uncertain if observations were of ova or some follicles with sperm ([Peden.sup.14]). Schultz et al. (1932), reporting on a 117 cm specimen, observed that the fish had “greatly enlarged and probably mature testes” Another example of tentative sex determination was made by the NMFS Auke Bay Laboratory on a 38 cm specimen (AB 61-38) taken in the Gulf of Alaska in September 1961 as follows: “The smaller one is in better condition and appears to be an immature female. The gonads are about 4 inches long and 1/4 to 1/2 inches broad. The material appeared granular and a few minute eggs could be separated” Ragfishes of intermediate sizes with questionable sex included two specimens taken 30 May 1962 in a midwater trawl (439-484 m) located 70-80 n.mi. west of Cape Flattery: a female 80 cm FL, 4.7 kg (BCFM: 972-62), and a male 99 cm FL, 6.9 kg (BCFM: 972-62).
Similar tentative decisions on sex were made on two intermediate-sized ragfishes taken in and around the head of Bodega Bay, Calif. A possible female measuring 77 cm was landed 10 January 1974 (CAS 31207), while the other was tentatively listed as a male 66.5 cm FL taken February 1963 (CAS 27468). One gonad in the HSU collection presenting an unusual appearance was listed as a presumed male of 100 cm FL (HSU 22) caught 23 April 1975 along the 400 fm (732 m) contour 25 miles west of Brookings, Oreg. The 24 cm long gonad filled the top of the abdominal cavity. The morphology that caused the curator’s questioning of this decision on the sex of the fish was not recorded.
Most ragfish delivered to HSU could be sexed. Roughly three times more female ragfish exist in HSU records as compared to other institutions (Table 2). Historically, females were almost always longer than males (Fig. 12), and with a slight overlap in weight (Fig. 13). Initially such a condition was assumed to be sexual dimorphism, although a difference in habitat by males as well as protandric hermophrodism were also possible explanations for the disparate sex ratio. Only one gonad with an external appearance suggesting internal differentiation (HSU 25) was examined histologically, showing testicular tissue throughout. The only historical record reporting a mature male from the eastern Pacific Ocean was a specimen of 167 cm caught November 1931 away from the open ocean in surface waters near Petersburg, Alaska (Schultz et al.,1932:65). The frst confirmed male adult ragfish (95 cm) from the western Pacific Ocean was documented by Kubota and Uyeno (1971). The first unequivocal male ragfish seen by the author (HSU No. 35, FL 139 cm; SL 123 cm) (Fig. 14) was caught by a trawl in 480 fm (878 m) on 17 July 1989 fishing 25 n.mi. due west of Point St. George, Calif. This analysis of ragfish catches indicated that commercial fishing gear in northern California and southern Oregon were not fishing in areas primarily inhabited by large maturing males, and thus the unbalanced sex ratios as recorded were primarily a function of sampling bias.
[FIGURES 12-14 OMITTED]
Most historical data available for documenting the reproductive biology of ragflsh came from recoveries by commercial and research trawling off southern Oregon and northern California (Table 8; Fig. 15, Areas B and C). The coastal bathymetry of Areas B and C shows a narrow continental shelf that only tends to spread westward north of central Oregon (see Fig. 1 in Pearcy, 1964). South of Cape Mendocino the continental shelf is relatively narrow and incised with submarine canyons. Over time the commercial bottom trawl fishery in Areas B and C moved to deeper waters beginning around 1970, with a yearly fishing pattern illustrated for both periods (Fig. 16). Most large ragfish (>35 cm FL) forwarded to HSU or CDFG were caught in Area B, with most of these coming from the northern portion of the area (Trinidad Head to Point St. George). Depths of trawls taking ragfish ranged from less than 44 fm (81 m) to over 620 fm (1,135 m) (Fig. 17). Female ragfish were caught more frequently in shallower depths than males in Area B (Table 9).
[FIGURES 15-17 OMITTED]
Fitch and Lavenberg (1968), on the basis of a single running-ripe female, postulated that a summer appearance of such large maturing females as shown for all west coast areas (Fig. 18) and Area B (Fig. 19) reflected a spawning movement onto the shelf. Such concentrations, however, could also have resulted from feeding behaviors. This hypothesis was examined by examining ragfish anatomy and studying food habits of ragfish along the continental shelf.
[FIGURES 18-19 OMITTED]
Adult ragfish have minute teeth in their jaws and a thin-walled digestive tract with no discernible differentiation between stomach and intestinal tract. This morphology is suited for consuming soft and readily digestible material. There are scant data in museums, literature records, or from recent records by biologists with personal knowledge of ragfish concerning stomach contents. Fitch and Lavenberg (1968) noted “small red jellyfish” in the stomach of a 27 cm juvenile recovered July 1962, 25 n.mi. east of San Clemente Island, as well as small fishes, squid, and octopuses in other specimens familiar to them. Research gear used to investigate scattering layers formed by walleye pollock, lantern fish (Myctophidae), and euphausids in lower Chatham Strait, Alaska, took a 130 cm adult ragfish which had consumed only lantern fish ([Bracken.sup.10]). Their midwater trawl was towed at 75 fathoms (137 m) over an ocean bottom of 300 fathom (549 m) depth.
Recorded observations by CDFG and HSU on the stomach contents of 34 ragfish caught in Area B (Table 8) showed about 65 percent of the stomachs empty or only containing traces of material. Specific comments on material seen in six stomachs were: “yellowish material at the lower end of the intestine,” or “runny orange liquid” Only a single stomach (106 cm female, HSU No. 4) had identifiable material, a single, 15 cm FL shortspine thornyhead, Sebastolobus alascanus. The rockfish’s red skin was clearly visible through the stomach wall and presumably the ragfish had consumed the rockfish while in or just prior to retrieval of the trawl net. The trawl occurred at 100 fm (183 m) southwest of Humboldt Bay. A second example of freshly consumed prey was that of an eelpout (Zoarcidae) found 8 August 1977 in the gullet of a 137 cm long ragfish caught 7 n.mi. west of the entrance to Humboldt Bay in 80 fm. Thus from HSU and CDFG data it appears that ragfish being taken off the continental shelf between Cape Mendocino and Trinidad Head were not in the area for any vigorous or sustained feeding.
The spawning time of ragfish was investigated by examining seasonal changes in the morphology of testes and ovaries from specimens primarily recovered from Area B. These changes included qualitative observations on the condition of ragfish testes, the relative change in size of ovaries of females throughout the year, and the change in mean diameter of large-category eggs in ovaries over time. Only four male ragfish taken off northern California and southern Oregon were available for comparative gonad size as indicators of spawning period. A small male, 77 cm SL (CAS 31207) taken January 1974 north of Bodega Canyon showed a “very thin testes” Relatively large and mature testes were noted in a specimen taken in late April 1975 (total testis length of 24 cm as compared to SL of 92 cm). Testes of a large male ragfish landed in Eureka, Calif., on 1 March 1989 were relatively small (25 cm maximum length in a 126 SL fish). The gonad showed typical testicular external morphology of lobate folds (2-3 cm in diameter) of creamwhite tissue. The right testis was nestled into the left testis, with the remaining anterior and posterior portions of both testes being very small in diameter. For a 139 cm TL ragfish landed in July 1989, both testes were 41 cm long (Fig. 14). Thus both full and depleted testes were noted in all seasons of the year. HSU ragfish and those measured at other institutions had right and left testes of equal length, or with either testis being larger. Lobulate tissue had developed at various positions along the testes, and varied in position between left and right testis. As another possible indicator of time of spawning, I calculated an index of relative length of the lobulate portion of testes (standard length divided by the length of the lobulate section). This index, when plotted against month of capture from Area B, suggested testis development most advanced in a late winter-early spring period (Fig. 20). Further comparative observations on testes from fish recovered in other seasons are needed to assess inferences on time of spawning based on testes morphology.
[FIGURE 20 OMITTED]
Females with ovaries having free-running eggs were captured at all seasons of the year (July-4; August-2; October, November, and January-1 each). Records on two females recovered in May had no comments as to eggs flowing from the vent but did have comments that eggs appeared relatively small. An index of relative size of ovaries plotted against time (Fig. 21) was highly variable, with a slight tendency for larger indices in spring. The strongest indicator of time of spawning, however, was found by a steadily increasing diameter for large-category eggs from late spring through summer and fall to early winter (Fig. 22).
[FIGURES 21-22 OMITTED]
In summary, this analysis of ragfish spawning time in northern California and southern Oregon based on testis and ovary maturity indicated a period from late winter to early spring. This is a slightly more restricted spawning period than that of late winter to early summer as previously proposed (Allen, 1968; Fitch and Lavenberg, 1968; Hart 1973).
The imprecise place of capture of a ragfish in the course of a bottom trawl makes it impossible to locate spawning areas even when data are available on gonads and coordinates at beginning and end of trawl hauls. Another approach to delineate a spawning location was made by examining the place of capture of these females showing the greatest diversity in their fecundity and also by examining the size and development of ragfish eggs. Four large females showed obvious disparity from a linear fecundity-weight relationship (Fig. 24). Catch details of these fish grouped into two sets (fish A and D, and fish B and C) are shown in Table 10. Females taken in the fall and winter (A, D) had the larger-sized eggs that were freely flowing from the vent, and they were both captured relatively near the north bank of the Eel River Canyon. Females captured in spring and summer (B, C) had the smaller-sized eggs, did not have eggs recorded as freely flowing from the vent, and were captured further away from the Eel River Canyon. As noted, the only ovary in the sample whose morphology indicated recent spawning was a specimen (HSU 8) taken 20 March 1969 off Bodega Bay in a commercial trawl of 270 fm (494 m) maximum depth. Unfortunately, there were no coordinates or directions to precisely locate the place of trawling, although it appeared to be near the head of Bodega Canyon.
A standard approach to delineating a possible time and place of spawning of a marine species utilized the size and development of eggs and larvae sampled over a probable spawning habitat. This approach was possible for ragfish using ELH data in both published and unpublished reports. The distribution of large eggs in icthyoplankton surveys could suggest a time and place of ragfish spawning since there are only a few marine species along the continental shelf with egg sizes as large as those of the ragfish and none with a similar distinct external pattern (Fig. 7).
Eggs with diameters similar to the “large category” eggs of ragfish were reported taken in February plankton samples off Eureka (Luczkovich (17)), but other ELH studies conducted by HSU faculty restricted to Humboldt Bay or nearshore waters found no ragfish eggs or larvae (Barnhart (18), Crandell (19)). Lack of eggs in shallow nearshore areas off Eureka may be related to a scarcity of adult ragfish in Area B nearshore as shown by the absence of ragfish reported from catches in commercial shrimp trawling in shallow waters (120 fm (220 m) or less) and/or in the salmon troll fisheries of the same areas off the northern California coast as compared to the consistent recoveries of ragfish from bottom trawlers operating in deeper waters to the west. In summary, these limited observations suggest a mesopelagic or mesobenthal spawning location, possibly associated with canyon heads along continental shelves.
Historically, fecundity (number of “large-category” eggs) calculated from ovaries of 5 large female ragfish captured in northern California-southern Oregon ranged from 230,000 to 430,000 eggs (Allen, 1968). Subsequently, an additional 9 females were available to expand this fecundity range to 144,000-552,000 eggs (Table 11). In historical records ragfish over 6 feet (183 cm, Fig. 2C) long were much longer than the females shown in Table 11 used in estimating ragfish fecundity. Lengths of the larger ragfish in the historical record were imprecise since authors reporting the data rarely examined the specimens personally. Sex of larger specimens also were rarely reported. One large specimen with accurate data was that of a 183 cm female reported by Pritchard (1929). I feel that the largest ragfish on record reported by Cowan (1938:208 cm) could be assumed to be a female. The weight of these 183 and 208 cm specimens were estimated by use of a length-weight regression calculated for the 14 females as listed in Table 11 ((In weight in kg) = -12,5500 + 2.16131n (length in mm); [R.sup.2] = 0.57; or weight = 3.544902 x [10.sup.6] x [length.sup.2.1613])). Predicted weights were 38.94 and 52.59 kg, respectively. Using regressions of fecundity against length (Fig. 23), the predicted fecundities were 640,000 and 883,000 eggs, while using fecundity against weight (Fig. 24) predicted fecundities were slightly lower: 608,000 and 813,000 eggs. Ragfish fecundity of over I million eggs should be expected, since specimens larger than the 208 cm ragfish probably exist (Cowan, 1938).
[FIGURES 23-24 OMITTED]
Ragfish appear to discharge eggs in a single short spawning burst. This is suggested by the lack of any difference in the mean size of large-category eggs in the ovaries (Allen, 1968 and Table 11 in this study). This idea was strongly supported by the recovery of one female as noted earlier taken 20 March 1969 off Bodega Bay at 270 fm (494 m) near the head of Bodega Canyon. The ovarian surface was highly vascularized and bleeding, virtually devoid of eggs, and had a few fragile and easily ruptured eggs running from the vents.
Temperature and Ragfish Life History
Ragfish are regarded as coldwater fish of the subarctic zoogeographic region of the North Pacific Ocean which lies north of the 8-10[degrees]C surface isotherm where it is associated with Bramidae (pomfret, Brama japonica), Anoplopomatidae (skilfish, Erelipis zonifer), and Salmonidae (Pacific salmon, Oncorhynchus spp., (Moyle and Cech, 1996: Fig. 26.2). It is likely the ragfish would respond to changes in location of surface isotherms as reported for other members of this assemblage (see papers in Wooster and Fluharty, 1985). Temperature records accompanying ragfish captures reported in NMFS databases (RACE and REFM) are in the normal “cold-water” range (7.5[degrees]10[degrees]C); however, temperatures as low as 2.5[degrees]C have been reported with ragfish taken at deeper depths (Fig. 25, 26).
[FIGURES 25-26 OMITTED]
Both minimum and maximum water temperatures recorded for ragfish catches occurred along the U.S. continental shelf. There were, however, a fairly large percentage of both small subadults, and even adults, recovered in warmer shallow waters, including surf zones. Presumably the eggs and larvae up to 3 cm TL that inhabit offshore surface waters are also in warmer waters.
Correlations of ragfish catches in 1962 with dramatic decreases in water temperatures off Japan in 1963 have been made by Abe (1963) and Nakai et al. (1964). The study involved over 35 juvenile and subadults caught from 21 March to 18 May 1963, only 800 m (0.5 mi) off the Pacific coast of Japan (Abe 1954, 1963). The catches were made along the 100 fm (183 m) contour which lies about 5 n.mi. offshore, beyond which the sea floor drops off sharply to a 500-700 fm (914-1,280 m) depth. The Japanese oceanographic surveys in the area were stimulated by the destruction of local fisheries from a replacement of the normal warm Kurisho current flowing north along the coast by large volumes of colder water as measured by oceanographic studies in 1963 in the Cape Manazuru area during late winter (25 January-20 March) and late spring (25 April-3 June) periods (Nakai et al., 1964). For the early spring studies, Nakai et al. (1964:62) concluded that “The temperature-chlorinity characteristic at the cold water area that occurred in the Sea of Kashima-Nada showed a very close resemblance to that of the sea in the northern Pacific which was reported as found in summer season. This fact suggests that this cold water was not an upwelling of bottom water but due to southern movement of Oyashio.”
Abe (1963), in reporting on the ragfish occurrences off Cape Manazurau, noted that one fish was taken 21 April 1963 when water conditions from 20-22 April at 2, 30, and 50 in depths varied from 13.8[degrees] to 14.6[degrees]C. In 1963, a few locations off the Pacific coast of Japan showed a 14[degrees]C drop in water temperature from 1962. Abe (1963) did not state what the normal warmwater temperatures for the area had been, but presumably the area reflected the usual 18[degrees]-19[degrees]C surface temperature along the Kurishio axis reported by Nakai et al. (1964). Abe (1963) also noted that other ragfish were recovered off the coast of Japan in 1953 during another cold-water year. The intrusion of pulses of cold waters, either by upwelling or southward movement of North Pacific waters, entrains ragfishes, making them susceptible to capture in the near-shore Japanese fisheries. Wing (11) also suggested that large ragfish caught in southeastern Alaska deepwater channels and inlets probably were entrained in surges or pulses of open ocean waters.
I did not attempt to study the correlations of inshore ragfish recoveries with possible occurrence of cold-water intrusions reported in recent literature (Wooster and Fluharty, 1985; McMurray and Bailey, 1998). El Nino effects, however, focus mostly on the changes in water temperature in ocean surface layers. The complex deeper ocean currents along the continental shelf of the eastern North Pacific Ocean (Greenland, 1998: Table 4.4) have not yet been sufficiently documented to be useful in understanding historical catches of ragfish with changing water temperatures. The known importance of temperature in the ecology of marine fishes (Karinen et al., 1985), the recent elaboration of coastal upwelling and eddy formation in the California Current system (Greenland, 1998: Fig. 4.31), and similar oceanographic phenomena off southern Alaska coasts, could be part of explaining how ragfish periodically appear in shallow continental waters and in deeper inlets and Fjords. As noted, the dead or moribund specimens which have been recovered by hand collections in the relatively warmer waters adjacent to beaches could come from a combination of a sensitivity to high temperatures, physiological stress from lack of a pneumatic duct, and an increased buoyancy in females carrying ovaries with eggs in advanced ripening stages. The southern boundaries of North Pacific regions of warm-cold water interfaces vary both with seasons and major changes in weather (McMurray and Bailey, 1998) (e.g. El Nino and La Nina events).
Cold-water intrusions both over continental shelf zones and upward into surface epipelagic waters could readily entrain ragfish into nominally temperate-water regions. Schoener and Fluharty (1985: Fig. 1, p. 212), reporting on a ragfish taken in 1983 in Hood Canal, Wash., listed the specimen as showing a “habitat anomaly.” Historical records of ragfish taken from inland marine waters of Washington and British Columbia support ragfish as normal residents and thus does not indicate the presence of the specimen was related to 1982-83 El Nino effects. There was some indication of a reduced recovery of ragfish from northern California waters following the 1976-77 and 1982-83 El Nino events (Fig. 4). Substantiating any warmwater avoidance behavior by ragfish would be difficult because of the complexity of nearshore currents off northern California (Allen, 1964) and the west coast continental shelf areas in general (Pearcy, 1964).
Ragfish populations distributed in the North Pacific Ocean along continental shelf zones from southern California to southern Japan might be expected to have differences in morphological and other biological characteristics. I did not attempt to compare meristics and morphometric data on adults listed in the literature, but I did attempt a cursory study of coloration and head morphology of eight juveniles illustrated (Grinols, 1965) or described in the literature, and of five juveniles (19-36 cm) preserved in the HSU fish museum (Table 12). Most juveniles illustrated or described in the literature showed a lateral head profile described as “trout-like” (Fitch and Lavenberg, 1971), except for Example C (Table 12) taken off San Pedro, Calif. Fifty years earlier in 1921, Higgins described the head of a 22 cm juvenile as follows: “The mouth was large, with thick lips, the nose broad and rounded, resembling with its large nostrils the muzzle of a calf” All five HSU juveniles shows this same broad, blunt-nosed profile a shape reflected in the line drawing of an adult ragfish illustrated in Hart (1973: 386). Hart (1973) also depicted a juvenile with the “trout-like” appearance. Thus, the uncertainty surrounding changes in head shape comes from both “trout-like” and “calf-like” head morphologies having been described for both juveniles and adults. Head profiles may thus vary with the eye of the illustrator and the audience. Hart (1973) summarizing the situation succinctly as “All that is known about the remarkable metamorphosis of this species from juvenile to adult is the change itself.”
Skin coloration and markings of fishes is highly variable as influenced by ontogeny and habitat. Not only does variability exist in the natural world, but changes in color and fading accompany immersion of specimens in preservatives. This problem was addressed in the initial description using two juveniles available to Lockington (1880) as follows:
“Color-Purple spots and blotches
of irregular shape upon a yellowish-brown
ground; the spots largest
upon the dorsal region, and becoming
smaller and more numerous near
the lateral line. The regions above
and behind the pectorals beset with
numerous purple spots, smaller
than those above the lateral line.
Beneath the lateral line, on the
posterior part of the body, there are
no spots, except along the line of the
anal; but probably this is the result
of the exposure to alcohol, which
has caused the disappearance of
most of the spots from the smaller
specimen, the color of which, when
fresher, was like that of the larger.
Throat and greater portion of gill-membranes
without blotches, but
shown with dark points, which
occur also over the whole of the
body and interior of the mouth.
Fleshy bases of caudal pectorals
with several purple blotches. Fins
darker than the body, and showing
traces of blotches of a deeper tinge,
especially upon the caudal.”
Lockington and other early ichthyologists did not have the possibility of colored photographs, and even colored illustrations were a luxury.
Gunther (1887) described color briefly in his description: “The fish is of a very light coloration, transparent below the dorsal and above the anal; its upper half is marked with large blackish spots, irregular in shape, smaller on the head and neck than on the rest of the body; they form a series along the base of the vertical fins, which are similarly spotted.” Goode and Bean (1895) listed a description similar to previous authors, and did not include any comments on the color of their illustrated specimen.
Accounts of the color of Japanese juvenile ragfish are rare, with Kamohara’s 1962 description including notes on color as follows: “Color pellucid yellowish, with purplish spots and blotches of irregular form; the spots largest upon dorsal region, and becoming smaller and more numerous near lateral line; pale below. Fins dusky, obscurely blotched, fleshy bases of candal and pectorals spotted.” Reexamination of juveniles in the HSU collection found two distinct skin colorations: very light to light skin color with prominent blotches and spots (19, 29 cm FL) and various shades of brown resembling adult skin color, with spots lacking (35, 36 cm FL and one specimen of 28 cm TL with missing tail). These data hint that skin coloration change is taking place simultaneously with reduction of the pelvic fins in a 30-36 cm range as documented by Komori (1993).
As would be expected, markings on juvenile ragfish undergo dramatic changes through larvae, juvenile, and adult stages. Watson (1996) reports that larvae less than about 2 cm have pigmentation as follows: “The light to moderate larval pigmentation occurs primarily on the head, gut, dorsum and finfolds and changes relatively during development.” Very few ragfish have been accessed or described during growth to around 15 cm. Black spots and blotches forming patterns on the skin of juvenile ragfish as illustrated or described in the literature (Table 12) with minor variations in these patterns are relatively similar for specimens from California (Table 12 A, B, C) and Japan (Table 12 I). A photograph of a juvenile from Japan showed a highly spotted pattern (Table 12 D), but may be the result of photographing a fresh juvenile (26 cm TL).
These markings differed somewhat from a 15 cm TL fish described in the same paper (Abe, 1954) as follows: “The black markings of the body are relatively much larger and less numerous, and the posterior half of the body is much thinner than in the specimen from Oya-mura; …” This comparison of Japanese specimens of different sizes was duplicated in part by a change in spotting with size found in the five northern California specimens. The smallest (19 cm SL) was uniformly covered with many blotches and large spots, while spotting was evident but hard to discern on a 29 cm FL specimen. No spotting was discernable on three larger juveniles (18+, 35, 36 SL). The juvenile illustrated by line drawing in Clemens and Wilby (1961) showed a uniform pattern of similar sized spots over the entire flanks, which I suggest is an artifact produced by the illustrator.
As with coloration, highly variable patterns of spots characterize juveniles from all parts of the North Pacific. Color photographs and descriptions of fresh-caught specimens are needed to ascertain if spotting might characterize local populations. Protein and DNA analysis might help to explain variability induced by environmental condition, and could lead to identifying possible distinctive populations in the species.
Other Life History Facets
The lateral line of adult ragfish is readily recognized as a prominent external structure (Fig. 3B). The young boys providing Bracken (10) with a large adult ragfish they found on a beach near Petersburg reported feeling tingles in their hands from handling the specimens, presumably from the spines associated with the lateral line. Descriptions of ragfish external morphology note that the lateral line is punctuated with modified scales or scutes in juveniles which become much reduced in adults (Cohn, 1906). He described in some detail the complicated lateral line in ragfish and associated structures (scales with and without spines), and compared them with other marine species. The smallish solid spines (less than 1 mm) growing out of several types of lateral-line scales have a complex association with pigmented and nonpigmented areas of skin. There were no described structures, however, that appeared to have toxic glands or secretory cells. If indeed reports on painful sensations that arise from handling living or moribund ragfish are true, pigmentations associated with skin may be a possible source of an irritating substance. Also there may be a lateral-line function in reproduction, such as the scales and spines acting as a tactile organ stimulating the release of eggs.
Possessing no scales and with only a cartilaginous skeleton, the ragfish is difficult to age using traditional methods. Otoliths were examined as a method of aging ragfish (Fitch and Lavenberg, 1971). Robert Behrstock, HSU fish collection curator, was unsuccessful at locating otoliths in large ragfish as indicated by entries into museum records. In January 1999, I examined a pair of otoliths removed by J. Fitch and preserved by L. Quirrolo, CDFG, Eureka, Calif., from a 115 cm ragfish. They were round, flattened, and only 1.5 mm in diameter. Fitch (20) reported unsuccessful attempts to interpret age from sections of otoliths, and was contemplating crystallographic and mineralogic studies. The only result of his preliminary aging of ragfish was that “An examination of otoliths of several ragfish 10 inches to 15 inches long indicates that the spotted phase lasts less than a year” (Fitch and Lavenberg, 1971: 80). Presence of modes in a length-frequency graph as indicators of fish age was equivocal for small (<35 cm) immature fish recorded in the historical data from museum collections (Fig. 9). The two modes neither negated nor affirmed Fitch's (20) statements.
Modes in length-frequency plots for ragfish >35 cm SL (Fig. 16) recovered off northern California and southern Oregon, were assumed to reflect the relative abundance of large maturing females and smaller males taken by the trawl fishery rather than any obvious age categories. A weight-frequency distribution of ragfish caught by NMFS research trawling operating on the continental shelf of the eastern North Pacific Ocean south of the Strait of Juan de Fuca suggested a first-year growth of up to 1 kg or less (Table 7). My initial analysis of the NMFS (RACE, REFM programs) ragfish size data, presented in this paper, supports the hypothesis of juvenile ragfish being more abundant at the southern end of their range in the eastern Pacific as well as in the western Pacific Ocean off Japan (Kubota and Uyeno, 1971).
Unravelling ragfish ecology undoubtedly will include information on population density. Estimation of population densities was not possible using historical analysis; however, there are recent reports on ragfish densities. Larkins (1964) calculated a density index of less than one ragfish per 100 shackles of gillnet fished in six areas of the North Pacific covered by Canadian research surveys. Currently, NMFS databases (RACE) can provide data for density estimates. The NMFS Observer Program (REFM) between 1990 and 1999 recorded 523 ragfish (Table 3, Fishery Observers, col. C) from all commercial fisheries of the west coast of the United States and the Bering Sea studied. This gives an average of only 52 ragfish per year recovered over the wide area covered.
A detailed study of the location and intensity of commercial bottom fisheries trawling efforts could be compared to ragfish recovery locations to study further the historical and the current hypothesis that ragfish populations have very low ragfish densities. A crude index of ragfish density, however, can be made from the number of specimens reported per year by the NMFS commercial fisheries observer and survey programs from 1976 to 1999. For all commercial fishing areas covered by the programs, the mean rate of recovery was 30/yr; for the U.S. west coast 5/yr; and for the Oregon and California coasts l/yr. This Oregon and California recovery rate is the same order of magnitude as found in the HSU/CDFG data bank of 2/yr for northern California from Cape Mendocino to Trinidad Head. For any area of interest a calculation of volume of water strained by all nets in individual fisheries, compared to the total water volume in a defined fisheries area, could also lead to a more quantitative ragfish density estimate but I leave that to younger computer generations.
Ragfish are now well known from epipelagic, mesopelagic, and upper bathypelagic zones, as well as the corresponding sea bottom zones (mesobenthal, bathybenthal) (Grinols, 1965). This apparently wide-ranging depth distribution ascribed to the ragfish seems reflected in its general morphology. A relatively large mouth, soft flesh, primarily cartilageous skeleton, dark brown to chocolate black skin, narrow caudal peduncle, and broad forked tail, absence of a swim bladder in adults and generalized feeding (anything from jellyfish to rockfish), are all characteristic of a robust, active swimmer that is capable of colonizing a wide range of ecological zones.
Circumstantial evidence that ragfish readily outdistance trawls towed at 2-3 kn comes from reports of ragfish lodged in the wings of trawl nets. This inferred rapid swimming ability makes it consistent with the species’ wide distribution by area and depth around the North Pacific Ocean and the Bering Sea. Thus I would expect range extensions to the Sea of Ohkotsk and off the Kamchatka Peninsula, even though Parin (1970) did not report any recoveries in those areas. Future ragfish recoveries may also come from upper mesobathyal depths, especially near the edge of sharply descending continental shelves and seamounts.
Most detailed new knowledge on ragfish presented in this paper deals with reproductive biology. The range of fecundity in the species has been enlarged and is probably now accurate for the species as a whole. By use of negative catch data from shallower-operating fisheries compared with positive catches from more deeply operating fisheries in the same areas, the potential spawning areas appear to be at least below the 120 fm (220 m) contour. Pinpointing an exact spawning location off northern California was not possible due to missing data in specimen records, but examination of egg and larvae distribution in recently published results of an early-life history investigation, targets deep channels or canyon heads as areas for future study.
Time of spawning was estimated by studying gonad morphology and maturity and mean size of eggs. Spawning time suggested in the literature, based on only a few female specimens with ripe eggs, was made more specific as the late winter-early spring period. Whether ragfish spawning behavior is social or occurs as isolated pairs or at least in small groups is not known, but females appear to discharge eggs in a single short burst suggesting mating in small groups or by isolated pairs. This might explain the current reduced number of males in samples. New ragfish recoveries having sex and size data are needed to fill our knowledge of the life history of the intermediate and smaller-sized adult ragfish. Known predators of ragfish now include species of Thunnidae, feeding on smaller specimens, with sperm whales, Physeter catodon, and Steller sea lions, Eumetopias jubatus, consuming larger adults.
Specimens known to science increased dramatically after World War II, undoubtedly due to the increase studies of oceanography, fisheries, marine biology, and higher education facilities being located along the eastern North Pacific coast. Research and educational programs that provided personnel with interest in non-game marine fishes and of species of no commercial import must also have played a role. Such contributing elements were well represented along the northern California coast. Ichthyologists such as Dan Gotshall and John Fitch working for the CDFG were just a few of past personnel working out of and through the Eureka office of the agency’s Marine Resources Branch that had to influence cooperation with fishermen in landing unusual fishes for inspection.
The fact that ragfish are not only “ugly” but generally large, would also make the species somewhat susceptible for retention and donation by fishermen. Historically, however, there has been difficulty in obtaining fresh specimens from fishermen. Higgins (1921) tried but failed: “We were unable to obtain the specimen as it was sold for exhibition?’ Fuknshima (21) reported a juvenile brought in by a vessel landing Pacific whiting, Merluccius productus (Ayres), (F/V Fishwish, 3 August 1999) at Eureka, Calif. Its length had to be estimated from memory as about 13 in (33 cm), and it was remembered as spotted and lacking pelvics. The fisherman was not willing to donate the specimen to science as it was aesthetically pleasing to him. Indeed, beauty is in the eye of the beholder.
Many facets of ragfish biology could be approached from maintaining a facility for the long-term housing of specimens. This requires a commitment from scientists and institutions, as well as funding for large tanks and refrigeration units. For example, loss of 10-12 adult ragfish (Fig. 4A) stored in the HSU hatchery, due to a compressor failure, seriously impaired planned morphological studies. It was exacerbated because a refrigeration unit normally available for backup storage was out of commission due to a building remodel project.
Additional ragfish knowledge can likely be readily obtained from records of incidental catches extant in files of individual fisheries biologists, marine scientists, governmental agencies, and other institutions studying marine fish populations of the North Pacific Ocean. The potential in such a retrospective study was demonstrated by a chance encounter in 1999 with M. Menghini, a graduate student in fisheries at HSU. He was in consultation with a faculty colleague when, inquiring with the faculty member, I mentioned ragfish. The student volunteered his knowledge of a ragfish specimen he had encountered during July 1993 when employed as an NMFS observer on the 242 ft stern trawler Sea Fisher operating in the Bering Sea and Gulf of Alaska. The specimen was between 5 and 6 ft (1.5-1.8 m) in length. He mentioned seeing the crew readily eat many species of fish other than the rockfishes caught by the vessel, but the ragfish was rejected for its limpness and “ugly” look (Fig. 27). No crew member had ever seen or heard of a ragfish. Menghini vaguely recalled a supervisor commenting on the rarity of species, since the supervisor only estimated about 1 in 500 vessels reporting a ragfish in their catches.
[FIGURE 27 OMITTED]
The Sea Fisher had operated for two months in the Bering Sea without previously encountering a ragfish. Such a fish ordinarily would not be noted in the records since it is not a targeted species in the official samples of the catch taken and processed by observers. Nevertheless, an inquiry as to the existence of such records incidental to the required catch data is an example of the potential untapped material on ragfish I was unable to investigate for this report until the appearance of the NMFS databases.
I found another interesting correlation between the recovery of a few juvenile ragfish (13-33 cm) off Japan’s Pacific coast (at the southern edge of ragfish distribution in the western North Pacific) and the four smaller specimens (29-42 cm) recorded by the NMFS research trawling off central California (Kubota and Uyeno, 1971). These data support the comments of Fitch and Lavenberg (1968, 1971) that “juveniles supposedly inhabit great depth, but fair numbers have been captured in relatively shallow water near the shore or near the surface offshore” This could be a chance correlation related to location of fishing effort. Precise information continues to be scarce for ragfish from about 5 cm to about 25-30 cm when small immature specimens begin in catches. Juvenile ragfish with their much more pronounced dentition than adults, and with lightish skin covered with irregular-shaped (blotchy) black spots appear adapted to life along or around rocky reefs or boulder piles. Such areas might lie just deep enough not to be targeted by hook-and-line sport fisheries or to be avoided by commercial fishing gear. I believe that suspended underwater video surveillance of such locations might be an initial inexpensive technique for identifying juvenile ragfish habitats, and observing a live adult.
Early literature mostly lists ragfish with “air bladder large” (Goode and Bean, 1895; Jordan and Evermann 1889; Regan, 1923); however, Gianther (1887: 46) quoted a description by Jordan and Gilbert (1881) (not seen) of a small 19 cm TL specimen from San Francisco as “without air bladder” Recent language on the topic states: “gas bladder is closed” (Hart, 1973). While examining available specimens of ragfish in the HSU collection for sex, no obvious gas bladders were noted unless the structure escaped notice by being distorted or atrophied in the formalin-fixed alcohol preservative. No statements concerning the presence or absence of air bladders, or other internal organs, were made in my records of female ragfish opened for removal of ovaries. Future investigations on ragfish internal anatomy could clarify this topic needed to understand ragfish depth distribution by age and size.
The bias inherent in samples from commercial gear and fishing techniques constrains the precision of results made from catch data, and this may continue to limit our understanding of distribution and life history of this fascinating and still puzzling species. Nevertheless, the fragmentary historical knowledge collected here does increase our understanding of one relatively uncommon deepwater species of fish and, more importantly, may serve as a model for additional studies on other little known or rare species as well as to stimulate more interest by marine scientists in the ragfish.
Ragfish Records Recovered in 1999
The challenge to incorporate highlights from the records of 621 ragfish collected by NMFS as received August 1999 has been discussed earlier. Prior to the surfacing of the NMFS data, however, there was another such late uncovering of ragfish records. These records are reported separately in this section.
During a visit with L. Quirrolo, CDFG, Eureka, Calif., to reexamine agency ragfish acquisitions, I noted ragfish records that apparently were neither in John Fitch’s nor in HSU files. On further analysis of a file containing 25 records, I found 13 fish that were not previously included in the historical records (Table 13). Most of the new information was not integrated into the main text, but some data were readily incorporated into text graphs. The number of ragfish added to the historical number of specimens known to science (Fig. 4B) from this set were: three specimens each for 1966, 1975, and 1978, and one fish each for 4 years scattered throughout a 1965-79 period. Lengths of nine ragfish were also added to the graphical history (Fig. 4C). Ragfish reported caught in 1975 and 1978 were relatively small (Table 13).
The limitation in synthesizing life history scenarios from specimens provided by volunteer donors as discussed previously was also evident in the CDFG data added in 1999. In the 1999 additions, most missing data involved weight and sex (only 31% and 23% complete in these categories, respectively). This was slightly different than the analysis of records of specimens utilized in the main text where most missing information involved location (49% complete) and weight (42% complete) (see Missing Data section in Materials and Methods). A plot of depth of capture vs. size of ragfish (Fig. 28) produced a pattern of smaller fish at deeper depths, but the relationship was probably biased by a preponderance of small fish in the sample. Sex was available for only three specimens (females), all over 100 cm in length. If the assumption were true that 50-80 cm long ragfishes not assigned a sex were either males or immature, it points to relatively deep habitats for ragfish around 50 cm in length off the northern California and Oregon coasts.
[FIGURE 28 OMITTED]
Little additional information on food habits was found in the new data. Only one specimen had a record listing stomach contents, and this was noted as empty. This again is consistent with the paucity of data on food habits as previously reported an assumption can be made that a “no comment” equates to an empty stomach.
The 13 new ragfish records showed ten different vessels contributing specimens, with two specimens coming from unknown sources. The names of the vessels and number of specimens contributed were as follows: Pearl Harbor (2), and one specimen each for Diana, Midnight Sun, Dennis Gayle, Karen Kelley, Blue Max, City of Eureka, Day Dream, Stephanie, and Admiral King. Vessels not previously recorded as catching rag fish in the new data set from northern California areas brought the total contributing vessels to 24. This examination of the 1999 data did not indicate any error or bias would occur to the analysis in the main text by not including this information, most of which came from ragfish caught in northern California fisheries.
Without the cooperation of owners, skippers, and deck hands of commercial trawlers in contributing ragfish caught off northern California ports, a major portion of this study would not have been possible. The names of these vessels along with the number of specimens contributed by each are: City of Eureka (7), Admiral King (4), Northern Light (3), Jeanne Arain (3), Stephanie (3), El Pescador (3), Pacific Pearl (2), Day Dream (2), and one specimen each from the Franklin, Empire 11, Intrepid, Miss Jo Anne, Katherine Anne, Sitka, Rainbow, Flicker, Clara G, El Carat, Ina, Diana, Midnight Sun, Dennis Gayle, Karen Kelley, and Blue Max. My thanks to David Hankin for assistance with statistics and his preliminary organization of ragfish data for mathematical analysis, to James R. Gast for aid in mapping ragfish catch locations, and to Gus Thiesfield for assistance in measuring testes of male ragfish extant in HSU collection in 1999.
An early draft of this paper was prepared for and presented at the 1989 meeting of the ASIH/AES held at San Francisco State University. The manuscript was reviewed by Tomio Iwamoto (CAS) and two anonymous colleagues. Their constructive reviews were most helpful in the development of this revised paper. Thanks especially to Heidi Banford, Fisheries Department, HSU, for reviews and suggestions for improving organization of the present work.
Unpublished papers prepared for a course in technical report writing (David Hankin, instructor) by HSU fisheries students Donald Bremm, Rick Sands, and Walter Osborn, provided regression equations used in estimating either length or weight for some specimens. Lynn Cordes, Humboldt State Fisheries Pathology Laboratory, prepared and stained sections of gonads of immature male ragfish selected for histological examination. Al Merrit, former HSU hatchery superintendent, processed specimens during 1976-77 when I was on sabbatical leave.
I am grateful to CDFG biologists stationed at Eureka, Calif., who stored fresh ragfish specimens or provided liaison with trawlers (Dan Gotshall, Paul Reid, Ron Warner, Emil Elman, Paul Dinnel, John Hanlon). Mike Fukushima, Pacific States Marine Fisheries Commission, Eureka, and Jim Waldvogel, University of California Extension agent at Crescent City also sequestered and forwarded specimens. Larry Quirrolo, CDFG, Eureka, supplied records as well as statistics on fishing effort, and information on commercial trawling operations. To the many unknown fishermen, for their interest in not discarding those ugly specimens, I extend a heartfelt thanks.
Robert Behrstock, former curator of the Humboldt State University ichthyological collection, aided in assembling information on accession data from other fish collections. To him and all curators listed who responded to his request for information on their ragfish accessions, my deepest appreciation.
Others assisting in various ways are gratefully acknowledged. Of major help were all former HSU students who counted samples of ragfish eggs in ichthyology classes. Jay Brown, Humboldt State University Graphics Department, prepared figures. Delores Neher and Kay Brisby, California Cooperative Fishery Research Unit, assisted with preparing manuscripts.
Jon Heifetz and Bruce Wing, research biologists with the National Marine Fisheries Service’s AFSC, Auke Bay Laboratory, Juneau, Alaska, were paramount in the retrieval and forwarding the ragfish data collected incidentally in the NMFS observer and research programs on commercial trawl fisheries of the west coast of the eastern North Pacific Ocean and the Bering Sea. I must acknowledge that Barry Bracken, retired fisheries biologist of the Alaska Department of Fish and Game, referred me to the NMFS personnel. Thanks to my colleague, Archie Mossman, retired professor of wildlife at HSU who forwarded me the article in Alaska magazine that resulted in my contacting Bracken.
My penultimate acknowledgment is John Fitch of the California Department of Fish and Game, who received, catalogued, and published on weird and strange fishes forwarded to him from all parts of California. There were specimens of ragfish landed in Eureka not entering the HSU collection that were documented by John and resulted in the largest historical non HSU file of California ragfish available for this study. In a letter in 1976 to Behrstock, John wrote that he was “… looking forward to seeing a synoptic report on all the ragfish known from our waters to date. Should I hold my breath?” Exhale, John, wherever you may be.
Because there are the relatively few publications, either primary or gray literature, with reports of original observations on ragfish, I hoped to compile a bibliography on the ragfish. Literature in journals with languages other than English cited by authors included in this paper were not all collected, and translations were not attempted. Publications mentioning ragfish but not containing primary material also were not included in my literature citations (i.e. textbooks, encyclopedias, distribution lists and keys to fishes, or monographs exploring specific fields such as fish morphology, marine biogeography, and ecology). The earliest ragfish citations are in the papers by Lockington (1880) and Bean (1887), with a large segment of the Japanese literature available in Abe (1963). Russian literature was not covered, although many such citations are listed by Japanese authors. Governmental and institutional documents, other than the RACE and REFM databases sent to me in August 1999, probably contain incidental catch data on ragfish not uncovered in this literature search.
Table 1.–Number and sex of ragfish Icosteus aenigmatic Lockington,
in historical records, 1880-2000.
Agency or institution and acronyms Male Female
California Department of Fish and Game (CDFG) 2 13
Humboldt State University (HSU) 11 23
Mail survey 1976-77:
Oregon State University (OSU) 1 1
California Academy of Science (CAS) 1 3
University of Washington School of Fisheries (UW) 1 0
British Columbia Provincial Museum (BCPM) 0 0
Six institutions 4 records or less (2) 0 0
Additions 1999, 2000 (3) 0 3
Agency or institution and acronyms Unknown Total
California Department of Fish and Game (CDFG) 16 31
10 13 (1)
Humboldt State University (HSU) 2 36
3 3 (1)
Mail survey 1976-77:
Oregon State University (OSU) 21 23
California Academy of Science (CAS) 7 11
University of Washington School of Fisheries (UW) 7 8
British Columbia Provincial Museum (BCPM) 7 7
Six institutions 4 records or less (2) 18 18
Additions 1999, 2000 (3) 15 16
(1) Additional CDFG records located December 1999, and of preserved
juveniles examined at HSU February 2000.
(2) University of California Los Angeles (UCLA); University of British
Columbia (UBC); Scripps Institution of Oceanography (SIO); Alaska
Department of Fish and Game, Auke Bay Labatory (ABL); United States
National Museum (USNM); Moss Landing Marine Laboratory (MLML).
(3) Alaska records from personal communications with Bracken (text
footnote 10), Wing (text footnote 11), Kondro (text footnote 12) and
in 1995, and Wing (text footnote 13).
Table 2.–Number of ragfish by sex recorded yearly from 1948
through 1977 by HSU and by other institutions (OI) surveyed by
letter August 1976. (1)
Female Male unknown Totals
HSU and OI
Year HSU OI HSU OI HSU OI HSU OI combined
1948 1 0 1 1
1952 6 0 6 6
1953 2 0 2 2
1954 2 1 0 3 3
1958 1 3 1 3 4
1960 1 1 0 1
1961 1 1 1 1 2 3
1962 2 2 2 2 4 6
1963 1 1 1 2 1 4 5
1964 1 0 1 1
1965 1 0 1 1
1966 1 0 1 1
1967 1 1 1 1 2
1968 1 1 0 1
1969 2 1 1 2 2 4
1970 1 2 6 1 8 9
1971 1 1 0 1
1972 2 2 0 2
1973 1 1 2 0 2
1974 2 1 1 1 3 4
1975 1 4 1 4 5
1976 3 2 3 2 5
1977 4 1 1 1 1 4 3 7
Total 20 15 5 3 0 33 25 51 76
(1) Additional historical data uncovered in 1990 and 2000 not
included (see footnotes in Table 1).
Table 3.–Number of ragfish recorded from commercial fisheries harvest
investigations (1) by areas (2) from 1976 to 1999 by the NMFS Auke Bay
Laboratory, Juneau, Alaska, 1976-99.
Fishery surveys Fishery RACE and REFM
(RACE) observers (REFM) combined
Year A B C A B C A B C
1976 2 1 1 2 1 1
1977 1 1 1 1 1 1
1978 1 1
1979 10 10
1980 7 5 2 7 5 2
1981 13 13
1982 19 19
1983 4 4
1984 1 1 1 1
1985 12 12
1986 3 3
1987 1 1
1989 2 1 5 7 1
1990 1 1 1 92 93 1 1
1991 80 5 5 80 5 5
1992 2 2 92 53 1 94 55 1
1993 8 8 2 45 53 8 2
1994 67 67
1995 3 3 2 35 8 3 38 11 5
1996 1 1 21 3 22 4
1997 15 2 15 2
1998 1 1 44 12 45 13
1999 (1) 32 32
Total 91 25 9 529 83 9 620 108 18
(1) Databases: 1) Survey program of the Resource Management and
Conservation Engineering Division (RACE) (n=91), and 2) Fishery
Observer program of the Resource Ecology and Fisheries Management
Service (REFM) (n=529).
(2) Geographic Areas: A = eastern North Pacfic Ocean, Gulf of Alaska,
and North America continental shelf combined; B = North American
continental shelf south of lat. 48[degrees]N; and C = Continental
shelf off Oregon and California (south of lat. 43.5[degrees]N).
Table 4.–Size, depth, and distance from coast of small juvenile ragfish
(5-50) cm range) caught over U.S. continental shelf, eastern North
Pacific Ocean listed in historical records, 1880-1990.
Depth (fm) No. Specimen Location/distance from coast (n.mi.) for
size (cm) underlined specimens
0-5 3 9, 15, juv Boat ramp, north jetty, Humboldt Bay,
5-25 2 17.5, 18.2 Off mouth of Columbia River
25-50 1 18.5 10 n.mi. W of San Pedro, Calif.
50-200 2 19, juv 10 n.mi. W of Redding Rock, Humboldt Co.,
100-300 1 43 S. of Arena Canyon (no distance listed)
300-500 1 50 14 n.mi. WSW of Punta Gorda, Calif.
Table 5.–Date, size, and distance from coast of ragfish < 17 cm caught
in surface by Oregon State University Department of Oceanography in
horizontal and oblique midwater trawis over continental shelf, eastern
North Pacific Ocean, off Oregon, 1962-76.
Range in depth of data
Date No. SL (cm) Trawling location (fm) (1,2)
8 Mar 62 1 6 40 n.mi. W of Cape Argo 0-100 Pearcy
25 Aug 66 1 7 59 n.mi. NW of Newport 0-500 Stein
15 Oct 66 1 juv 70 n.mi. W of Cape
Fowlweather 0-600 Pearcy
14 Nov 70 3 1.5-3.0 65 n.mi. NW of Newport 0-45 Stein
6 Jul 70 1 5 19 n.mi. SW of sand spit,
south entrance to Columbia
River 0-1.5 Stein
6 Jul 70 1 11 19 n.mi. SW of sand spit,
south entrance to Columbia
River 8-15 Stein
20 Jul 76 1 5 80 n.mi W of Tillamook Bay 0-18 Pearcy
21 Aug 82 1 4 78 n.mi. W of Heceta Head 0-0 Pearcy
24 Aug 82 2 8-11 78 n.mi. W of Heceta Head 9-18 Pearcy
24 Aug 82 1 13 78 n.mi. W of Heceta Head 13-13 Pearcy
24 Aug 82 2 3-6 78 W of Heceta Head 145-154 Pearcy
No date 5 7-14 No data Stein
No date 1 16.5 85 n.mi. W of Columbia
River mouth Pearcy
21 1.5-16.5 Range from coast 19-85
(1) Pearcy, W. Oregon State Univ., Corvallis. Personal commun., 1999.
(2) Stein, D. 1976. Response to survey by R. Behrstock, 1976-77.
Table 6.–Weight of ragfish caught by NMFS research
(RACE) during trawling along the continental shelf of
the eastern North Pacific Ocean and in the Bering Sea,
No. of specimens
Range in Shelf Bering Sea
weight (Lat. 36[degrees]N- (Lat. 51[degrees]N-
(kg) Lat. 48[degrees]N) Lat. 60.2[degrees] N) Combined
<0.1 4 4
>0.1-1.0 13 2 15
>1.0-5.0 2 1 3
5-10 11 11
10-15 11 11
15-20 10 10
20-25 1 7 8
25-30 1 11 12
30-35 2 2
35-40 1 1 2
40-45 1 1
Totals 22 57 79
Table 7.–Weight of ragfish by depth of trawis caught
by NMFS research (RACE), eastern North Pacific
Weight (kg) No. Min. Mean Max.
<1.1 23 38 244 623
3.5-7.5 6 211 340 601
8-15 19 30 299 495
15-25 19 147 263 425
25-37 18 115 301 435
Combined 85 30 289 623
Table 8.–Recovery areas used for analysis of historical data on
reproduction and other aspects of ragfish biology in the eastern
North Pacific Ocean, 1899-1989.
Principle ports of
Area ragfish recovery
N Washington, British Columbia, and Gulf
A Oregon coast north of Point St. George Brookings, Oreg.
B Point St. George south to Cape Crescent City, Calif.
Mendocino, Calif. Eureka, Calif.
Ft. Bragg, Calif.
C Cape Mendocino to Point Arena, Calif. Bodega Bay, Calif.
D Point Arena to Farallon Islands, Calif.
E Farallon Islands to Point Sur, Calif.
S Central and southern California coast
Table 9.–Difference in depth of capture (1) between
number of male and female ragfish taken in commercial
otter trawis operating between Trinidad Head and Cape
Mendocino, northern California, 1958-89.
Number by sex
Trawl depth (fm) Male Female Total
<350 2 15 17
>350 8 3 11
Total 10 18 28
(1) Chi-squared test of hypothesis that there is no difference
in depth distribution between sexes using Yates continuity
correction, equation 6.8, p.64, in Zar, 1968: [chi square] = 8.32;
df = 1; P = <0.005.
Table 10.–Capture Information and biological indices for four
specimens of regfish with maximum variation from fecundity-weight
regression (fish numbers A-D, Fig. 21).
Fish no. Date captured Approximate location
A 29 Oct 67 8 n.mi. west of Eureka, Calif.
B 13 Jul 72 19 n.mi. west McKinleyville, Calif.
C 21 May 74 Off Redding Rocks, Calif.
D 2 Jan 62 North edge of Eel River Canyon, Calif.
Gonado-tropic Mean egg Free-flowing
Fish no. Depth (fm) index diameter (mm) eggs
A 330-290 14.1 2.6 Yes
B 44 18.3 1.6 Not recorded
C 180-250 9.2 1.6 No
D 180-190 30.9 2.7 Yes
Table 11.–Fecundity estimation of total number of “large-diameter”
eggs for 14 female ragfish recovered from commercial trawl fisheries
of the eastern North Pacific Ocean over the northern California and
southern Oregon continental shelf (area B, Table 8), 1958-81.
Total Ovarian case
HSU Weight Length (cm) ovarian weight weight (g)
fish no. (kg) TL (SL) (g) (TOW) (OCW) (1)
1 26.2 150 (135) 1,647 (92.8)
3 30.0 150 (127) 3,402 (139.2)
4 19.5 119 (106) 989 (74.0)
5 23.1 129 (124) 3,339 176
6 21.6 143 (124) 5,942 209.0
7 26.8 122 (106) 2,236 (107.7)
9 7.9 89 (85) 516 (61.2)
13 12.2 125 (101) 680 60.7
14 15.4 129 (112) 1,918 (99.0)
15 24.4 129 (115) 2,590 84
20 25.6 142 (125) 1,805 125.9
21 14.4 135 (121) 803 65.0
23 21.8 133 (122) 1,523 107.3
24 14.5 128 (106) 930 60.7
eggs and Average Fecundity
ovarian no. eggs (thousands
HSU tissue (g) per g of of eggs)
fish no. (TOW-OCW) (A) tissue (B) (A x B)
1 (1,554) 260 404
3 (3,263) 79 257
4 (915) 265 242
5 3,163 123 390
6 5,733 92 527
7 (2,128) 184 391
9 (455.1) 250 114
13 619.7 250 155
14 (1,819.0) 148 270
15 2,506.1 220 552
20 1,679.4 310 521
21 739.9 274 202
23 1,415.7 231 327
24 869.2 288 250
(1) OCW shown in parentheses estimated from regression of ovarian
case weight against ovary weight as follows: OCW =0.027 (TOW)
+47.3, n = 7, R = 0.92.
Table 12.–Published Illustrations showing coloration pattern
and snout profile of juvenile ragfish.
Example Author and location
A Gunther (1887), Pl. XLIV
B Goode and Bean (1895), Fig. 224, Pl. LXII
C Fitch (1953), Fig. 4, p. 545
D Abe (1954), Fig. 3, p. 94
E Abe (1954), p. 94
F Clemens and Wilby (1961), Fig. 138a, p. 235
G Kamohara (1962), Fig. 3, p.6
H Hart (1973), p.386
I Allen, G.H., and G. Theisfield (1)
Example Type of illustration size (cm)
A Line drawing 18-28 (n=2)
B Line drawing
C Photograph 20
D Line drawing 26
E (Written description)
F Line drawing
G Photograph 27
H Line drawing
I Preserved, HSU museum 19-36 (n=5)
Example Place of recording or capture
A San Francisco, Calif.
B San Francisco, Calif.
C San Pedro, Calif.
D Oya-mura, Northern Japan
E Manazura, central Japan
F Strait of Juan de Fuca,Canada
G Urado Bay, Kochi City, Southern Japan
I Northern California
(1) Observation on specimens.
Table 13.–Data of 13 ragfish found 22 March 1999 in files of
California Department of Fish and Game, Marine Resources, Eureka,
Calif. (not recorded by John Fitch or HSU).
CDFG no. Date Location (1)
136-65 23 Sep 65 2410-2550
152-66 3 Apr 66
164-66 11 Jun 66 2365-2260
182-66 14 Aug 66 100 fm W Fort Bragg
293-69 18 Mar 69 38[degrees]08’N-123[degrees]34’W
0018-75 18 Dec 75 1H6-2900
0019-75 2 Jun 75 1H6-2600
0015-75 23 Jul 75 1H6-1800
008-78 15 Aug 78 Block 2625
0009-78 28 Aug 78 2140-2100
0013-78 Sep 78 Near Crescent City, Calif.
0008-79 16 Jun 79 Off Coos Bay, Oreg.
Number with data 12 11
Percent with data 92 85
CDFG no. Depth (fm) Length (cm) Wt (kg) Sex
140-65 shallow 115 F
152-66 102 F
164-66 240 114 F
0018-75 340-350 50 TL 0.59
0015-75 310-320 70 FL (80 TL) 3.2
008-78 50-450 45 TL
0009-78 67 19 SL (22 TL)
0013-78 28 SL (32 TL) 0.35
0008-79 340 81 SL (92 TL) 4.2
Number with data 10 10 4 3
Percent with data 77 77 31 23
CDFG no. Vessel
140-65 Pearl Harbor
152-66 City of Eureka
164-66 Admiral King
293-69 Pearl Harbor
0018-75 Midnight Sun
0019-75 Dennis Gayle
0015-75 Day Dream
0009-78 Karen Kelly
0008-79 Blue Max
Number with data 11
Percent with data 85
(1) As listed on available records. Numerical descriptions are
Loran C readings overprinted on U.S. Coast and Geodetic Survey
charts, and CDFG marine fisheries block numbers.
(1) Heifetz, J. National Marine Fisheries Service, Auke Bay Laboratory, 11305 Glacier Hwy, Juneau, AK 99801-8626.
(2) INPFC. 1992. Scientific review of north Pacific high seas driftnet fisheries, Sidney B.C., June 11-14, 1991. Joint report by the National Sections of Canada, Japan, and the United States for a United Nations meeting hosted by Can., Dep. Fish Oceans, Inst. Ocean Sci., 86 p.
(3) McKinnell, S., Y. Watanabe, H. Nakano, H. Hatanaka, S. Ota, M. Dahlberg, L. Jones, S. Fitzgerald, W. Thogmartin, J. Wetherall, and P. Gould. 1992. Final report of observations of the Japanese high seas large-mesh driftnet fishery in the north Pacific Ocean 1990-1991. Joint Rep. Fish. Agency Jpn., Can. Dep. Fish. Oceans, U.S. Natl. Mar. Fish. Serv., NOAA, and U.S. Fish Wildl. Serv., 86 p.
(4) Yeh, S-Y, J. Sha, M. Dahlberg, L. Jones, S. Fitzgerald, J. Wetherall, and P. Gould. 1991. Final report of the 1990 observations of the Taiwanese high seas driftnet fisheries in the north Pacific Ocean. Joint Rep. Republic of China Council of Agric., U.S. Natl. Mar. Fish. Serv. and U.S. Fish Wildl. Serv., 83 p.
(5) Park, J. S., Y. Gong, Y. S. Kim, D. H. An, S. J. Hwang, M. Dahlberg, L. Jones, S. Fitzgerald, J. Wetherall, and P. Gould. 1991. Final Report. 1990 observations of the Korean high seas squid driftnet fishery in the north Pacific Ocean. Joint Rep. Republic Korea Natl. Fish. Res. Develop. Agency, U.S. Natl. Mar. Fish. Serv. and U.S. Fish Wildl. Serv., 75 p.
(6) Institution acronyms are identified in Table 1.
(7) Fitch, J. Marine Biologist, Calif. Dep. Fish Game, deceased.
(8) Unpubl. term project reports, Tech. Writing, Fish. Dep., Humboldt State Univ., Arcata, Calif., Spring 1980, D. G. Hankin instructor: Osborn, W. M., Spawning characteristics of the brown ragfish Icosteus aenigmaticus, 20 p.; Sands, R. S., Sex differences, fecundity and spawning of the brown ragfish, Icosteus aenigmaticus, 14 p.; and Bremm, D., Size, fecundity, and spawning characteristics of the brown ragfish, Icosteus aenigmaticus, 19 p.
(9) HSU 1831; June 12, 1983.
(10) Bracken, B. E. 1999. Alaska Dep. Fish Game, Petersburg, Alaska. Personal commun.: Letter and phone.
(11) Wing, B. L. 1999. Auke Bay Laboratory, Natl. Mar. Fish. Serv., NOAA, Juneau, Alaska. Personal commun.: Letter, and phone.
(12) Kondro, L. B. 1995. Kake, Alaska. Personal common.: Letter to B. L. Wing, 1999 phone call to G. H. Allen.
(13) Wing, B. L. 2000. Auke Bay Laboratory, Natl. Mar. Fish. Serv., NOAA, Juneau, Alaska. Personal commun.: Letter, phone, or e-mail.
(14) Peden, A. E. 1976. Mar. Biol. Div., B.C. Prov. Mus., Vancouver. Personal commun.: Letter to R. Behrstock.
(15) Stein, D. 1976. Oreg. State Univ., Corvallis. Personal commun.: Letter to R. Behrstock.
(16) Bitts, D. 1999. N. Calif. Troll Fisherman’s Assoc., Eureka, Calif. Personal commun.
(17) Luczkovich, J. 1989. Adjunct Prof., Humboldt State Univ. Fish. Dep., Arcata, Calif. Personal commun.
(18) Barnhart, R. 1999. Calif. Coop. Fish. Res. Unit, Humboldt State Univ. Personal commun.
(19) Crandell, G. 1999. Dep. Oceanogr., Humboldt State Univ. Personal commun.
(20) Fitch, J. E. 1976. Operations Res. Branch, Calif. Dep. Fish Game. Personal commun.: Letter to R. Behrstock.
(21) Fukushima, J. 1999. Pac. Mar. Fish. Commiss., Eureka, Calif. Personal commun.
Abe, T. 1954. New, rare or uncommon fishes from Japanese waters. IV. Records of rare fishes of the families Lophotidae, Nomeidae, and Icosteidae. Jpn. J. Ichthyol. 3(2):90-95.
–. 1963. Unusual occurrence of several species of boreal, amphipacific and bathypelagic fishes in Sagami Bay and adjoining waters during the first half of 1963, a cold water season in southern Japan. Bull. Tokai Reg. Fish. Res. Lab. 37: 27-35.
Allen, G. H. 1964. An oceanographic study between the points of Trinidad Head and the Eel River. Calif. State Water Quality Control Board, Publ. 25, 135 p.
–. 1968. Fecundity of the brown ragfish, Icosteus aenigmaticus Lockington, from northern California. Calif. Fish Game 54(3): 207-214.
–, A. C. DeLacy, and D. W. Gotshall. 1961. Quantitative sampling of marine fishes–a problem of fish behavior and fishing gear. In Proceedings of the First International Conference on Waste Disposal in the Marine Environment, 22-25 July, 1959, Univ. Calif., Berkeley, p. 448-509. Pergamon Press, N.Y.
Bailey, R. M., E. A. Lachner, C. C. Lindsey, C. R. Robins, E M. Roedel, W. B. Scott, and L. E Woods. 1960. A list of common and scientific names of fishes from the United States and Canada. 2nd ed. Am. Fish. Soc., Spec. Publ. 2, 102p.
Barnhart, P. S. 1936. Marine fishes of southern California. Univ. Calif. Press, Berkeley, 209 p.
Bean, T. H. 1887. Description of a new genus and species of fish, Acrotus willoughbyi, from Washington Territory. Proc. U.S. Natl. Mus. 10:631-632.
Berg, L. S. 1940. Classification of fishes, both recent and fossil. Tr. Zool. Inst. Akad. Nauk SSSR 5:87-517 [in Russ.].
Bolin, R. L. 1940. Brown ragfish at Monterey. Calif. Fish Game 26(3):287-289.
Clemens, W. A., and G. V. Wilby. 1949. Fishes of the Pacific coast of Canada. Bull. Fish. Res. Board Can. 67:1-308.
— and –. 1961. Fishes of the Pacific coast of Canada. Bull. Fish. Res. Board Can. 68:1-443.
Cohn, L. 1906. Die Seitenlinie von Icosteus anigmaticus. Zool. Ariz. 30:178-183.
Cowan, I. M. 1938. Some fish records from the coast of British Columbia. Copeia 1938(2): 97.
Crawford, D. R. 1927. Records of rare fishes from the North Pacific during 1925. Copeia 1927 (160):182-184.
Dean, B., E. W. Gudger, and A. W. Henn. 1923. A bibliography of fishes. Vol. III. Am. Mus. Nat. Hist., N.Y., 707 p.
Eschemeyer, W. N., and E. S. Herald. 1983. A field guide to Pacific coast fishes of North America from the Gulf of Alaska to Baja California. Houghton Mifflin, Boston, 336 p.
Fitch, J. E. 1953. Extensions of known geographical distributions of some marine on the Pacific coast. Calif. Fish Game 39(4):539-552.
— and R. J. Lavenberg. 1968. Deepwater teleostean fishes of California. Calif. Nat. Hist. Guides 25, Univ. Calif. Press, Berkeley, 155 p.
— and –. 1971. Marine food and game fishes of California. Univ. Calif. Press, Berkeley, 179 p.
Goode, G. B., and T. H. Bean. 1895. Oceanic ichthyology. A treatise on the deep-sea and pelagic fishes of the word, based chiefly upon the collections made by the steamers Blake, Albatross, and Fish Hawk in the northwestern Atlantic. U.S. Natl. Mus., Spec. Bull. 2, 553 p.
Gosline, W. A. 1973. Functional morphology and classification of teleostean fishes. Univ. Press Hawaii, Honolulu, 208 p.
Greenland, D. 1998. Variability and stability of climatic/oceanic regimes in the Pacific northwest. In G. R. McMurray and R. J. Bailey (Editors), Change in Pacific Northwest coastal ecosystems: Pacific Northwest Coastal Ecosystems Regional Study (PNCERS), p. 91-179. U.S. Dep. Commer., Coast. Ocean Off., NOAA Coastal Ocean Program, Decision Anal. Ser. 11.
Greenwood, P. H., D. E. Rosen, S. H. Weitzmen, and G. S. Meyers. 1966. Phyletic studies of teleostean fishes with a provisional classification of living forms. Bull. Am. Mus. Nat. Hist. 131(4):334-356.
Grinols, R. B. 1965. Check-list of the offshore marine fishes occurring in the northeastern Pacific Ocean, principally off the coasts of British Columbia, Washington, and Oregon. Coll. Fish., Univ. Wash., Seattle. M.S. Thesis. 217 p.
Gunther, A. 1887. Report on the deep-sea fishes collected by H.M.S. Challenger during the years 1873-76. Zool. Challenger Expedition, Pt. 57, 335 p.
Hart, J. L. 1973. Pacific fishes of Canada. Fish. Res. Board Can., Bull. 180, 740 p.
Higgins, E. 1921. A strange rag fish at San Pedro. Calif. Fish Game. 7(3):179.
Jordan, D. S., and B. W. Evermann. 1898. The fishes of north and middle America. Part II and HI. Bull. U.S. Natl. Mus. 47:1241-3136.
— , B. W. Evermann, and H. W. Clark. 1930. Check-list of the fishes and fishlike vertebrates of north and middle America north of the northern boundary of Venezuela and Columbia. U.S. Dep. Commer., Bur. Fish., Rep. U.S. Commiss. Fish. for FY 1928, Pt. 2, 670 p.
Kamohara, T. 1962. Notes on six additions to the marine fish fauna of Kochi Prefecture, Japan. Rep. USA Mar. Biol. Sta. 9(2): 1-6.
Karinen, J. F., B. L. Wing, and R. R. Straty. 1985. Records and sightings of fish and invertebrates in the eastern Gulf of Alaska and oceanic phenomena related to the 1983 El Nino event. In W. S. Wooster and D. L Fluharty (Editors), El Nino north. Nino effects in the eastern subarctic Pacific Ocean, p. 253-267. Univ. Wash. Sea Grant Prog., Seattle.
Kobayashi, K., and T. Ueno. 1956. Fishes from the northern Pacific and from Bristol Bay. Bull. Fac. Fish., Hokkaido Univ. 6(4):239-265.
Komori, K. 1993. Osteological development of ragfish (Icosteus aenigmaticus Lockington). Humboldt State Univ., Arcata, Calif., M.S. Thesis, 116 p.
Kubota, T., and T. Uyeno. 1971. First record of an adult specimen of ragfish from Japan. Jpn. J. Ichthyol. 18(1):51-54.
Larkins, H. A. 1964. Some epipelagic fishes of the North Pacific Ocean, Bering Sea, and Gulf of Alaska. Trans. Am. Fish. Soc. 93(3): 286-290.
Lockington, W. N. 1880. Description of a new genus and some new species of California fishes (Icosteus aenigmaticus and Osmerus attenuatus). Proc. U.S. Natl. Mus. 3:63-68.
Marsh, K. 1995. Too ugly to eat. Alaska 61(1): 70.
Matarese, A. C., E. G. Stevens, and W. Watson. 1984. Icosteoidei: development and relationships. In H. G. Moser, W. T. Richards, D. M. Cohen, M. P. Fahay, A. W. Kendall Jr., and S. L. Richardson (Editors), Ontogeny and systematics of fishes, p. 576-577. Am. Soc. Ichthyol. Herpetol. Spec. Publ. 1.
–, A.W. Kendall, Jr., D. M. Blood, and B. M. Winter. 1989. Laboratory guide to early life history stages of northeast Pacific fishes. U.S. Dep. Commer., NOAA Tech. Rep. NMFS 80, 652 p.
McMurray, G. R., and R. I. Bailey (Editors). 1998. Change in Pacific northwest coastal ecosystems. U.S. Dep. Commer., Coast. Ocean Off., NOAA Coast. Ocean Program, Decision Analysis Ser. No. 11, 342 p.
Miller, D. J., and R. N. Lea. 1972. Guide to the coastal marine fishes of California. Calif. Dep. Fish Game, Fish. Bull. 157, 249 p.
Moser, H. G., R. L. Charter, P. E. Smith, D. A. Ambrose, S. R. Charter, C. A. Meyer, E. M. Snadknop, and W. Watson. 1993. Distributional atlas offish larvae and eggs in the California current region: Taxa with 1000 or more total larvae, 1951 through 1984. CalCOFI Atlas No.31, 233 p.
— , — , — , — , — , — , –, and –. 1994. Distributional atlas of fish larvae and eggs in the California current region: Taxa with less than 1000 total larvae, 1951 through 1984. CalCOFI Atlas No. 32, 181 p.
Moyle, P. B., and J. J. Cech, Jr. 1996. Fishes. An introduction to ichthyology. 3rd ed. Prentice Hall, Upper Saddle River, N.J., 590 p.
Nakai, Z., S. Hattori, K. Honjo, T. Watanabe, T. Kidahi, T. Okutan, H. Suzuki, S. Hayashi, M. Hayalshi, K. Kondo, and S. Usami. 1964. Preliminary report on marine biological anomalies on the Pacific coast of Japan in early months of 1963, with reference to oceanographic conditions. Bull. Tokai Reg. Fish. Res. Lab. 38:57-75.
Nelson, J. S. 1976. Fishes of the world. John Wiley and Sons, Inc. N.Y., 416 p.
Parin, N. J. 1970. Ichthyofauna of the epipelagic zone. [Translated from Russ.] Isr. Program for Sci. Transl., Jerusalem, 206 p.
Pearcy, W. G. 1964. Some distributional features of mesopelagic fishes off Oregon. J. Mar. Res. 22:83-102.
Peden, A. E. 1974. Rare fishes including first records of thirteen species from British Columbia. Syesis 7:47-62.
Pritchard, A. L. 1929. A ragfish (Icosteus aenigmaticus) from Queen Charlotte Islands, B.C. Copeia 1929 (171):38.
Regan, C. T. 1923. The fishes of the family Icosteidae. Ann. Mag. Nat. Hist. 9(11):610-612.
Schultz, L. P. 1930. Miscellaneous observations on fishes of Washington. Copeia 1930(4): 137-140.
–. 1936. Keys of the fishes of Washington, Oregon, and closely adjoining regions. Univ. Wash. Publ. Biol. 2(4):71.
— and A. C. DeLacy. 1936. Fishes of the American northwest. Part 2. Mid-Pac. Mag., Jan.-Mar. 1936:63-78.
— and –. 1935-1936. Fishes of the American northwest. A catalogue of the fishes of Washington and Oregon, with distributional records and a bibliography. Jpn. Pan-Pac. Res. Inst. 11(2):71.
–, J. L. Hart, and F. J. Gunderson. 1932. New records of marine west coast fishes. Copeia 1932 (2):65-68.
Schooner, A., and D. L. Fluharty. 1985. Biological anomalies in 1982-83 and other major Nino periods. In W. S. Wooster and D. L. Fluharty (Editors), El Nino North. Nino effects in the Eastern Subarctic Pacific Ocean, p. 211-225. Wash. Sea Grant Prog. Wash., Seattle, USA, 312 p.
Steindachner, F. 1881. Ichthylogische beitrage. XI. Sitzungaber. kais. Akad. Wiss. Wein, Math.-Naturh. Klass., LXXXIII. Abth. 1, 393-408 pp, 1 pI. (not seen. Cited by Gunther, 1887, and Abe, 1954).
Taylor, F. H. C. 1967a. Midwater trawl catches from Queen Charlotte Sound and the open ocean adjacent to the Queen Charlotte Islands. Fish. Res. Board Can., Tech. Rep. 11:44.
–. 1967b. Unusual fishes taken by midwater trawl off the Queen Charlotte Islands, B.C. J. Fish. Res. Board Can. 24(10): 2101-2115.
Thompson, W. F. 1921. A rag fish at Monterey, California. Calif. Fish Game 7(3):179.
Ulrey, A. B., and P. O. Greeley. 1928. A list of the marine fishes (Teleostei) of southern California with their distribution. Bull. S. Calif. Acad. Sci. 27(1):1-53.
Watson, W. 1996. Ragfish. In H. G. Moser (Editor), The early stages of fishes in the California Current region, p. 1201-1202. Calif. Coop. Oceanic Fish. Invest. Atlas 33. Allen Press, Inc., Lawrence, Kan., 1505 p.
Wheeler, A. 1975. Fishes of the world. MacMillan Publ. Co., Inc. N.Y., 366 p.
Wilmovsky, N. J. 1954. List of the fishes of Alaska. Stanford Ichthyol. Bull. 4(5): 279-294.
Wing, B. L., C. W. Derrah, and V. M. O’Connell. 1997. Ichthyoplankton in the eastern Gulf of Alaska, May 1990. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-75, 42 p.
— and D. J. Kamikawa. 1995. Distribution of neustonic sablefish larvae and associated ichthyoplankton in the eastern Gulf of Alaska, May 1990. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-53, 48 p.
Wooster, W. S., and D. L. Fluharty (Editors). 1985. El Nino north. Nino effects in the eastern subarctic Pacific Ocean. Univ. Wash. Sea Grant Program, Seattle, 312 p.
Zar, J. H. 1984. Biostatistical analysis. Second ed. Prentice Hall, Englewood Cliffs, N.J., 718 p.
George H. Allen is Professor Emeritus, Fisheries, Department of Fisheries, Humboldt State University, Arcata, CA 95521.
COPYRIGHT 2003 U.S. Department of Commerce
COPYRIGHT 2004 Gale Group