International Council ICES CM 2003/Q:09 for the Exploration Theme Session Q: Regional Long-Term Changes of the Sea in the Spatial Distribution, Abundance, and Migration of Pelagic and Demersal Resources

Possible ways of exchange between Asian and American ichthyofaunas in the North Pacific Ocean

Alexei M. Orlov

Russian Federal Research Institute of Fisheries & Oceanography (VNIRO), 17, V. Krasnoselskaya, Moscow, 107140, Russia [tel: +7 (095) 264-91-43, fax: +7 (095) 264-91-87, e-mail: [email protected]]

Abstract

Till present only continental slope of the Bering Sea was considered as the way, along which some typical representatives of American ichthyofauna are able to migrate or its pelagic eggs/larvae may be transported to Asian coasts (Pacific halibut Hipposlossus stenolepis, shortraker rockfish Sebastes borealis, Atheresthes stomias, rex sole zachirus, sablefish Anoplopoma fimbria). Recent studies showed that exchange between Asian and American ichthyofaunas exists along Kuril and Aleutian Islands. Some species extended their ranges from the Aleutians to Kuril Islands and southeastern Kamchatka (northern rockfish Sebastes polyspinis, dusky rockfish Sebastes ciliatus, arrowtooth flounder, and rex sole) due to recent climatic changes. Some species described from the Aleutian Islands (blacktip snailfish Careproctus zachirus, longfin Irish lord zapus, scaled sculpin Archaulus biseriatus, sponge sculpin Thyriscus anoplus, and roughskin sculpin Rastrinus scutiger) were recently found in the Pacific waters off Kuril Islands and are in this area abundant or common. Above species occurred off the Aleutians very rare and are represented mostly by small-sized immature specimens while off the Kurils their adults are very common. Therefore it may be suggested that pelagic eggs or larvae of these species may be transported from the Kuril Islands to the Aleutians by the Western Pacific Gyre waters.

Keywords: ichthyofauna, exchange, eggs, larvae, range extension, migrations, transfer, continental slope, Kuril Islands, Kamchatka, Aleutian Islands, Bering Sea

Introduction

Ichthyofauna of temperate waters of the North Pacific Ocean is characterized by particular originality and represents separate zoogeographic (boreal Pacific) region (Andriashev 1939a). Despite significant similarities, within this region two sub-regions may be distinguished: Asian (Far East) and Oregonian, which fish species compositions essentially differ (Schmidt 1904, 1950; Andriashev 1939b; Fedorov 1978; Allen and Smith 1988). These differences related to different sources of origin of ichthyofaunas in both areas (Indo-West-Pacific for Asian sub-region and East- Pacific for Oregonian one) and to its long existence separately each from other (Schmidt 1948). Representatives of Oregonian ichthyofauna are distributed mostly off the western American coast (California, Oregon, Washington, British Columbia), in the Gulf of Alaska, off the Aleutian Islands, and in the eastern and southern Bering Sea. In Asian waters these species occur only occasionally. In their turn, Asian species are distributed mainly in the northwestern Pacific Ocean (Sea of Okhotsk, western Bering Sea, and the Pacific waters off Japan, Kuril Islands and Kamchatka). These species occur off American coast very rare. It is thought that in the past exchange of ichthyofaunas between Asia and America had mutual character and was realized along Bering Sea continental slope and Aleutian-Kuril arch (Kodolov et al. 1991). In present period only continental slope of the Bering Sea is considered as the main way of such exchange (Novikov 1961). Though Wilimovsky (1964) hypothesized possibility of westward range extension of some Aleutian fishes. Recently it was suggested (Dudnik et al. 1998) that juvenile sablefish Anoplopoma fimbria is able to migrate from the Aleutians in the Kuril Island and Kamchatka waters. Studies conducted during 1992-2002 in the western Bering Sea and the Pacific waters off the northern Kuril Islands and southeastern Kamchatka allowed receiving new data on recent exchange between Asian and American ichthyofaunas. This paper provides new data on distribution of some fishes, inhabiting waters off both Asian and American coasts, and considers possible exchange paths of American and Asian ichthyofaunas.

Material and methods

This paper is based on catch data obtained from 21 bottom trawl surveys (total over 1,500 bottom trawl stations made during 1992-2002) and numerous bottom trawl hauls conducted during commercial operations from southeastern Kamchatka and northern Kuril Islands area. The investigated area is within 47º30´ N to 52° N, 154º20´ E to 158º50´ E. Samples were collected from three chartered commercial Japanese trawlers (Tomi-Maru 53, Tomi-Maru 82, and Tora-Maru 58). Catch data sampled aboard Japanese trawler Kayo-Maru 28 in the western Bering Sea (168° E – 178° W) during bottom trawl survey and commercial fishing operations in summer 1997 were also used. Bottom trawl surveys were conducted during the daytime, commercial fishing operations were conducted around the clock at depths 76-833 m using a 5-7 m (vertically) by 25-30 m (horizontally) bottom trawl net constructed from 100-120 mm (stretched mesh) polyethylene net. The net was outfitted with steel and rubber ball roller gear in the forward wings. Only successful trawl samples (horizontal and vertical net openings remained within normal range, the roller gear maintained consistent contact with the bottom, the net suffered no or little damage during the tow, there were no conflicts with derelict fishing gear) were used for analysis in the present study. Most hauls were made along isobaths. Hauls with highly variable depths between the start and end of towing were excluded from the analysis. Data on captures of scaled sculpin Archaulus biseriatus, sponge sculpin Thyriscus anoplus, roughskin sculpin Rastrinus scutiger, and longfin Irish lord Hemilepidotus zapus in the southern Bering Sea and off the Aleutian Islands were obtained from electronic fish collection databases of the California Academy of Science, National Museum of Natural History, University of Washington, Scripps Institute of Oceanography, University of British Columbia, Kiel University, British Museum of Natural History, Museum National d’Historie Naturelle, and Museum of Zoology of Hokkaido University that are available via FISHBASE web site (http://www.fishbase.org). Data on captures of above species and of blacktip snailfish Careproctus zachirus, arrowtooth flounder Atheresthes stomias, dusky rockfish Sebastes ciliatus, northern rockfish Sebastes polyspinis, rex sole Glyptiocephalus zachirus, juvenile sablefish Anoplopoma fimbria were taken from published sources (Peden 1979; Nelson 1984; Kido 1985; Matarese and Vinter 1985; Dudnik et al. 1998; Sheiko and Tranbenkova 1998; Poltev and Moukhametov 2000; Chetvergov 2001; Orlov 2001a; Orlov and Moukhametov 2001; Orlov et al. 2001, 2002; Tokranov 2002).

Result and Discussion

Range extension along the Bering Sea continental slope. Pacific halibut Hippoglossus stenolepis is permanent dweller of the Asian waters. Due to its origin from the northeastern Pacific (Kodolov et al. 1991) and highest abundance off American coast the Asian waters may be considered as the western edge of species range. Condition of gonads, existence of juveniles, adults with developing gonads, spawning and ripe fish are evidence of normal reproduction of Pacific halibut within Asian waters (Orlov 2000). Since species considered is capable to perform lengthy migrations (Kaimmer 2000), adult Pacific halibut may move from American coast in the Asian waters along continental slope of the Bering Sea. It is possible also assume that Pacific halibut abundance within the Asian waters is substantiated due to periodical replenishment by eggs or/and larvae transported by current from the northeastern Pacific. Sablefish Anoplopoma fimbria is an endemic species of the North Pacific. It is typical representative of American ichthyofauna (Novikov 1961; Allen and Smith 1988; Kodolov et al. 1991). This species is most abundant within eastern part of the Pacific Ocean while in the Asian waters sablefish abundance is relatively low and considerably fluctuates in long-term aspect (Sasaki 1984). Since this species is able to perform lengthy migrations (Tuponogov and Kodolov 2001) and its young was never caught in the Bering Sea (Kodolov 1986), it is possible assuming that sablefish, inhabiting the western Bering Sea, is represented by fish migrated from American waters to perform there temporal dependent population (Parin 1988). Capability of arrowtooth flounder Atheresthes stomias to perform lengthy migrations is well known (Shuntov 1966; Novikov 1961). It may migrate in the western Bering Sea from eastern part of the sea along continental slope that may be confirmed by similarity of species size composition in both areas (Orlov 2000). Hypothesis of arrowtooth flounder eggs drift from the northeastern Pacific in the western Bering Sea and eastern Kamchatka waters (Dolganov 2000) are not confirmed yet, because there are no young caught in these areas but only large mature fish represented bulk of catches. Rex sole Glyptocephalus zachirus and dusky rockfish Sebastes ciliatus, in our opinion, are able to penetrate into the western Bering Sea from its eastern part also along continental slope, though not due to active migrations (above species are not good swimmers) but due to gradual range extension during long-term warming. Numerous captures of rex sole young in the western Bering Sea in the late 1990´s (Glubokov pers. comm.) may indicate favorable environmental conditions for spawning of species considered or its eggs survival transported here by currents from the eastern Bering Sea due to recent climatic changes. Above path of ichthyofaunas exchange between Asia and America is known for a long time and is considered as traditional way (Novikov 1961; Kodolov et al. 1991). Thus, our studies confirm previous data on active migrations of Pacific halibut, sablefish, and arrowtooth flounder from the eastern Bering Sea in the western part. (Fig. 1). Besides, data obtained show possibility of range extension of dusky rockfish and rex sole from the eastern to western Bering Sea along continental slope.

Hypothesis of shortraker rockfish migrations in the Bering Sea. Shortraker rockfish Sebastes borealis is an endemic species of the North Pacific Ocean. It is distributed from Japan (39°50´ N) and southern California (40°46´ N) to the Bering Sea. This species is considered commercially important off eastern Kamchatka, the northern Kuril Islands, the Aleutian Islands region, and in the Bering Sea and Gulf of Alaska. Shortraker rockfish has pelagic larvae and juveniles (Matarese et al. 1989). Its life history is poorly studied. Information important for rational management of the species such as stock structure and the degree of mixing among populations is still missing. Questions such as whether these species perform lengthy migrations or whether discrete populations exist are unanswered. Some recent publications dealing with its genetic and parasitologic studies (Moles et al. 1998; Gharrett et al. 2000) attempted to answer the above questions. Though shortraker rockfish is still considered as non-migrating fish (Parker et al. 2000). The analysis of shortraker rockfish size composition data from the Bering Sea showed that its maximum abundance occurs in the western part of the area. Juveniles are most abundant in the eastern Bering Sea while very few juveniles are caught in the western part of the area (Bakkala et al. 1992; Harrison 1993; Ronholt et al. 1994; Orlov 2001b). Shortraker rockfish is a long-lived species (Beamish and McFarlane 1997) with late sexual maturation and low growth rates (McDermott 1994). Large interannual fluctuations in abundance or size-age structure variations are not pronounced. Seasonal and multiannual variations in size composition, taking into account the low reproductive rate and insignificant harvest rate cannot be explained by fluctuations in abundance and, according to our hypothesis, should be related to horizontal migrations. Size composition data, benthic juvenile spatial distribution and ocean current patterns in the North Pacific Ocean (Orlov 2001b) indicate that in the Bering Sea, the main spawning area is probably the continental slope from Cape Navarin and the Commander Islands and along the northwestern and central Aleutian Islands (Fig. 2). The following model may explain the pattern of shortraker rockfish migrations. Most larvae originating in the western Bering Sea are transported eastward. Some of larvae are probably transported by the Eastern Kamchatka current to eastern Kamchatka and the Kuril Islands and through straits in the central Aleutian Islands into the Pacific Ocean. Some larvae and/or pelagic juveniles may linger within quasi-stationary anti-cyclonic eddies around seamounts, near straits and in areas where currents form a junction. These conditions can result in temporal dependent populations that are regularly replenished by fish migrating to and from feeding areas. Taking into account the prevailing oceanographic conditions, such populations are most likely to be inherent in the Aleutian Islands areas. The minimum length of shortraker rockfish benthic juveniles from bottom trawl catches is about 10 cm corresponding to an age of about two years (Orlov and Abramov 2001). It is thought that after shortraker rockfish juveniles settle out, the adults remain relatively stationary and do not engage in lengthy migrations (Barsukov 1981). This conclusion however may only be valid for small-sized specimens. Recent investigations show that increasing size is accompanied by migratory behavior. Thus, small shortraker rockfish consumed mainly benthic and fishes (Yang 1996), while large specimens feed mostly on squids and mesopelagic fishes (Yang 1993) inhabiting the water column. To feed on squids and mesopelagic fish, shortraker rockfish need to perform vertical migrations. We suggest that with an increase in size, this species is able to perform not only vertical, but also horizontal migrations. In the Bering Sea, adult shortraker rockfish have been captured in deep water far from coastal waters (Balanov and Radchenko 1995). Size composition from long-line and gill net catches may also substantiate the assumption that shortraker rockfish are capable of performing horizontal migrations. These passive fishing gears are deployed in stationary locations for relatively long time periods while the spatial distribution of shortraker rockfish is characterized by sporadic movement and considerable distance between individual fish (Krieger 1992). Therefore, high CPUE´s obtained in the long-line and gill net fisheries may be explained by fishes actively moving to the fishing gear. Shortraker rockfish begin to occur in long-line and gill net catches at lengths greater than 30 cm but predominantly in the 40-45 cm and larger range (Tokranov and Davydov 1998). Submersible observations (Krieger and Ito 1999) showed that this species is able to swim at a speed of 1 km/h, while the average speed of bottom currents in the Bering Sea does not exceed 0.8 km/h (Stabeno et al. 1999). Comparison of current data in the Subarctic Pacific region with above facts suggests that shortraker rockfish complete lengthy migrations.

Range extensions from the Aleutians to Kurils due to climatic changes. This path of distribution of American ichthyofauna in the Asian waters was determined during second half of the 1990´s. Abundance of arrowtooth flounder in the Pacific waters off the northern Kurils and southeastern Kamchatka sharply increased since the 1997 (Fig. 3). Only incidental captures of large fish were observed in this area in the 1994-1995. In the 1997-1998 arrowtooth flounder catches in study area dramatically increased. By this fish was represented mostly by juveniles. Maximum number of captures of species considered in the eastern Sea of Okhotsk off Kamchatka was registered also in the 1997 (Chetvergov 2001). In this area, arrowtooth flounder was found in the 1996 only once and after 1997 its captures there essentially decreased. The possible reason of arrowtooth flounder penetrating into the Kuril Islands and Kamchatka waters may be associated with range extension from the Bering Sea along continental slope. Though results of studies conducted in the western Bering Sea during the 1990´s (Orlov 2000) showed that main arrowtooth flounder aggregations within the Russian EEZ located east of 180° and west of 173° E its catches were insignificant. Besides species considered in above area are represented exclusively by large fish with length of 43-72 cm (mean 54.8 cm). These facts indicate that expansion of fish from the Bering Sea cannot be considered as the cause of arrowtooth flounder abundance increasing off Kurils and Kamchatka. Another reason of arrowtooth flounder abundance increasing in the area of study may be related to transfer of its pelagic fry by currents from adjacent regions. Dolganov (2000) hypothesized that eggs of this species may be transported by currents very far from reproductive areas. Above hypothesis looks doubtful because settlement of arrowtooth flounder juveniles occurs at length of 40-43 mm (Bouwens et al. 1999a) and in the northwestern Pacific its bottom young in catches become frequently having length of 14-18 cm (Shuntov 1966). Catches from the Pacific waters off the Kurils and Kamchatka did not comprise such individuals. Minimum length of arrowtooth flounder was 28 cm that correspond to the age over 3 years (Bouwens et al. 1999b). Arrowtooth flounder caught off Kuril Islands and Kamchatka according to number of caudal vertebrae and gill rakers is very similar to fish originated from the northeastern Pacific Ocean (Mukhametov and Orlov 2002). Comparison of fish size composition from Kurils and Aleutians waters showed its similarity in both areas considered (Orlov 2000). Taking in account all above facts, the reason of dramatic increasing of arrowtooth flounder abundance off Kamchatka and Kutil Islands is concerned to its westward range extension from the Aleutians as result of significant warming of the northwestern Pacific Ocean during late 1990´s and of considerable weakening of the East Kamchatka current (Khen 1997; Hare and Mantua, 2000). Hypotheses of particular role in exchange between Asian and American icthyofaunas along the Aleutian-Kuril Islands arch were previously suggested (Wilimovsky 1964; Kodolov et al. 1991; Dudnik et al. 1998). In the second half of the 1990´s considerable number of northern rockfish Sebastes polyspinis captures were observed (Fig. 4). This species was not registered in the area of study previously. Northern rockfish was not found during the 1990´s in the western Bering Sea as well. Size composition of this species in the Pacific waters off Kamchatka and Kurils, analogously with arrowtooth flounder, was very similar to that of Aleutian fish (Orlov 2000). Since 1993 dusky rockfish started to occur off Kamchatka and Kuril Islands as occasional captures (Fig. 5). In 1993 and 1996 it was caught off Commander Islands, in 1997 it was found off the southern tip of Kamchatka (cape of Lopatka) (Sheiko and Tranbenkova 1998), and later it occurred within entire study area from 48°16′ N to 51°25′ N (Biryukov, Nemchinov, Tokranov, Zolotov, unpubl. data). Recently, captures of typically eastern Pacific , rex sole, in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka became more frequent (Fig. 6). There are several possible hypotheses that may explain recent records (Tokranov and Vinnikov 2000; Orlov et al. 2002) of rex sole in the Pacific waters off the northern Kuril and southeastern Kamchatka. The rex sole appears to have a continuous distribution from California along the Gulf of Alaska, Aleutian Islands and Bering Sea, through the Commander Islands and eastern Kamchatka, to the northern Kuril Islands. The absence of recorded specimens before the 1980´s and 1990´s may be due to the fact that the inshore fish fauna of the region has been poorly studied. Rex sole were recently reported off the northern Kuril Islands and southeastern Kamchatka (Borets 1997, 2000; Sheiko and Fedorov 2000), but no documented specimens were kept to verify these collections. Since the rex sole has pelagic larvae and juveniles (Matarese et al. 1989) its young may be carried from the Aleutian Islands or Bering Sea to the Kuril Islands by currents. Settlement of rex sole may occur at length 49-72 mm (Alstrom et al. 1984; Matarese et al. 1989). Juveniles of this species at one year of age and about 10 cm in length are occasionally caught in British Columbian waters (Hart 1973). Rex sole caught in the Pacific waters off the northern Kuril Islands and south-eastern Kamchatka were 20-40 cm long which corresponds to an age of 3-12 years (Novikov 1974). It may therefore be possible to hypothesize that after settlement the fish remained in the area for several years, although no individuals less than 20 cm long had ever been caught previously. Thus we doubt that specimens reported here originated from pelagic young carried by currents into the area in question. We think that rex sole found in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka may have originated from the Aleutian Islands or Bering Sea as a result of range extension due to considerable warming of the northwestern Pacific during the 1990´s (Hare and Mantua 2000) and weakening of the East Kamchatka current (Khen 1997). Captures of sablefish yearlings in waters off the Kuril Islands and Kamchatka in the 1990´s became frequently (Fig. 7). Population status of sablefish, inhabiting the Asian waters, is still uncertain. Kodolov (1986) suggested that fish of the Bering Sea and Pacific waters off the Kuril Islands and eastern Kamchatka are represented by specimens migrated from the northeastern Pacific, and the Asian waters for sablefish are eviction area. Dudnik et al. (1998) assumed that replenishment of sablefish stocks off Kurils and Kamchatka is not only due to adults, migrating from the Bering Sea along continental slope, but also due to transfer of yearling by the Aleutian current from American coast. Novikov (1994) conversely considered the Asian waters (including the Sea of Okhotsk) as areas of permanent sablefish distribution and as component of its wide range in the North Pacific. It is also hypothesis (Parin 1988) that dependent sablefish population exists in the Bering Sea, where its abundance depends on stock size in reproductive areas. Recent captures of prespawning, spawning, and ripe sablefish in the Pacific waters off Kuril Islands and Kamchatka prove its spawning on the southwestern edge of the area (Orlov and Biryukov 2003) that was traditionally considered as species eviction zone. However, study of survival of sablefish fry in this area requires conducting of specialized ichthyoplankton surveys, and determination of sablefish population status here requires respective genetic research. Thus, ranges extension of some Aleutian fish species westward to the Kuril Islands may be illustrated by following scheme (Fig. 8).

Transfer of pelagic eggs and/or larvae from the Kurils to Aleutians by the Western Subarctic Gyre waters. Exchange by ichthyofaunas between Asian and American waters, according to our opinion, may exist in direction from Kuril Island to the Aleutians as well. Results of faunistic studies confirm such possibility. It is possible to assume that scaled sculpin Archaulus biseriatus found at Petrel Bank in the Bering Sea by Gilbert and Burke (1912) and recently caught off the Aleutians specimen (Orlov et al. 2001) may have originated from the Kuril Islands because they were represented by smaller specimens of 80.9-129.2 mm, while larger individuals of 150-159 mm were caught off the northern Kuril Islands. This suggestion is substantiated by the fact that abundance of scaled sculpin off the Kuril Islands is considerably higher (Fig. 9) then that off the Aleutians. Besides several recent captures (Yabe and Sonma 2000; Orlov et al. 2001) fish collection of Zoological Institute of the Russian Academy of Science (St.-Petersburg) contains more than twenty scaled sculpins caught off the Kuril Islands in the 1980´s by A.A. Balanov (Shieko pers. comm.). Longfin Irish lord Hemilepidotus zapus was described from the southern Bering Sea off Aleutian Islands (Gilbert and Burke 1912). It was thought for a long time that this species inhabits only waters off the Aleutian and Commander Islands, where mostly juveniles with length less than 173 mm occurred (Peden 1979; fish collections databases). Recent studies showed that longfin Irish lord is one of most abundant cottids off the central Kurils mainly distributed within the underwater plateau southeast of Shiashkotan Isl. (Fig. 10) and represented there mostly by mature fish sized up to 260 mm (Tokranov and Orlov 2001a). Since abundance of longfin Irish lord off the Kuril Islands is essentially higher than that off the Aleutians, it is possible assuming periodical drift of large number of its pelagic fry from Kurils to Aleutians and further wide dispersion of young in latter area. This assumption may be supported by periodical findings of longfin Irish lord larvae in the southern Bering Sea, for instance during the 1977-1980´s (Matarese and Vinter 1985) and in 1992 (University of Washington electronic fish collection database), which may not be originated from Kuril Islands waters. Blacktip snailfish Careproctus zachirus was also described from the Aleutian Islands (Kido 1985) by fore specimens with length of 23.6-25.2 cm. Since description only few captures of this species in above area were recorded (Orr pers. comm.). Recent studies showed that blacktip snailfish is rather common species in the Pacific waters off the Kuril Islands and Kamchatka (Fig. 11) most frequently occurred within above-mentioned underwater plateau, where its length varied 19-32 cm (Tokranov and Orlov 2001b). Until recently, only waters off the Aleutian Islands were considered as inhabitation area of roughskin sculpin Rastrinus scutiger and sponge sculpin Thyriscus anoplus (Gilbert and Burke 1912; Nelson 1984), where mostly their young with length of 34.5-85 mm and 58-121 mm respectively was captured (Nelson 1984; fish collection databases). Resent studies showed that roughskin sculpin is rather common off central Kurils within underwater plateau located southeast of Shiaskotan Isl. (Fig. 12), where this species is represented by adult fish having length 100-160 mm with mean 120 mm (Tokranov and Orlov 2002). Sponge sculpin is also rather common off central Kuril Islands (Fig. 13), where catches comprised specimens sized 84-145 mm with mean length 112 mm (Tokranov 1998). Taking in account that most of sculpins and snailfishes have pelagic larvae and fry (Matarese et al. 1989), it is possible to hypothesize that captures of species considered off the Aleutian Islands are due to transfer of its pelagic fry from the Kuril Islands by the western Subarctic Gyre waters (Fig. 14).

Conclusion

Thus, despite traditional view, according to which exchange between Asian and American benthic and bentho-pelagic ichthyofaunas may occur only along Bering Sea continental slope, new data are received supporting hypothesis that some species may migrate from the Aleutian Island waters to Kuril Islands, eastern Kamchatka, and even in the Sea of Okhotsk due to westward ranges extension under the influence of recent climatic changes in the North Pacific Ocean. It is possible also reversal exchange of American and Asian ichthyofaunas from central Kuril Islands to the Aleutians through open oceanic pelagial due to transfer of pelagic fry. By this distribution of new faunistic elements for long distance and assimilation in areas with existing faunistic complexes occur rapidly, during several years.

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Matarese, A.C., Kendall, A.W., Jr., Blood, D.M., and Vinter, B.M. (1989) Laboratory guide to early life history stages of northeast Pacific fishes. U.S. Department of Commerce NOAA Technical Report NMFS 80, 1-652. Moles, A., Heifetz, J., and Love, D.C. (1998) Metazon parasites as potential markers for selected Gulf of Alaska rockfishes. U.S. Fishery Bulletin 96, 912-916. Mukhametov, I.N., and Orlov, A.M. (2002) The morphology of arrow-toothed flounders of the genus Atheresthes of Pacific waters of the northern Kuril Islands and southeastern Kamchatka. Biologiya Morya 28, 196-202 (In Russian). Nelson, D.W. (1984) Systematics and distribution of cottid fishes of the genera Rastrinus and Icelus. Occasional Papers of the California Academy of Science 138, 1-58. Novikov, N.P. (1961) New data on the distribution of halibuts and some other commercial fishes in the Bering Sea. Zoologicheskii Zhurnal 40, 1510-1515 (In Russian). Novikov, N.P. (1974) Commercial fishes of the northern Pacific Ocean continental slope. Moscow, Pishchevaya Promyshlennost’. 308 p. (In Russian). Novikov, N.P. (1994) New captures of sablefish Anoplopoma fimbria in the Sea of Okhotsk. Voprosy Ikhtiologii 34, 843-845 (In Russian). Orlov, A.M. (2000). Representatives of Oregonian ichthyofauna off the Asian coasts. P. 187-214 In: B.N. Kotenev (Ed.). Commercial and biological studies of fishes in the Pacific waters of the Kuril Islands and adjacent areas of the Sea of Okhotsk and Bering Seas. Moscow, VNIRO Publishing (In Russian). Orlov, A.M. (2001a) Features of spatial and vertical distribution of representatives of the oregonian ichthyofauna off the Asian coasts. Byulleten’ Moskovskogo Obshchestva Ispytatelei Prirody. Otdel Biologicheskii 106, 23-37 (In Russian). Orlov, A.M. (2001b) Ocean current patterns and aspects of life history of some northwestern Pacific scorpaenids. P. 161-184 In: G.H. Kruse et al. (eds.). Spatial processes and management of marine populations. University of Alaska Sea Grant, AK-SG-01-02, Fairbanks. Orlov, A.M., and Abramov, A.A. (2001) Age, rate of sexual maturation, and feeding of the shortraker rockfish, Sebastes borealis (Scorpaenidae) in the northwestern Pacific Ocean. Journal of Ichthyology 41, 279-288. Orlov, A.M., and Mukhametov, I.N. (2001) Arrow-toothed halibuts Atheresthes spp. (, Pleuronectiformes) off the northern Kurils and the south-eastern Kamchatka. Report 1. Distributional patterns. Voprosy Rybolovstva 2, 258-274 (In Russian). Orlov, A.M., Tokranov, A.M., and Vinnikov, A.V. (2001) Additional records of scaled sculpin Archaulus biseriatus Gilbert & Burke, 1912 (Teleostei: Cottidae) from the North Pacific. Aqua, Journal of Ichthyology and Aquatic Biology 5, 11-18. Orlov, A.M., Tokranov, A.M., and Biryukov, I.A. (2002) New records of rex sole Glyptocephalus zachirus Lockington, 1879 (Teleostei: Pleuronectidae) from the north- western Pacific. Aqua, Journal of Ichthyology and Aquatic Biology 5, 89-98. Orlov, A.M., and Biryukov, I.A. (2003) New data on spawning of sablefish Anoplopoma fimbria (Anoplopomatidae, ) in the Pacific Ocean off Kuril Islands and Kamchatka. Byulleten’ Moskovskogo Obshchestva Ispytatelei Prirody. Otdel Biologicheskii 108, 20-25. Parker, S.J., Berkeley, S.A., Golden, J.T. et al. (2000) Management of Pacific rockfish. Fisheries 25, 22-30. Parin, N.V. (1988) Fishes of the high seas. Moscow, Nauka. 271 p. (In Russian). Peden, A.E. (1979) A systermatic revision of the hemilepidotine fishes (Cottidae). Syesis 11, 11-49. Poltev, Yu.N., and Moukhametov, I.N. (2002) New captures of yearlings of sablefish Anoplopoma fimbria in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka. Voprosy Ikhtiologii 40, 288 (In Russian). Ronholt, L.L., Teshima, K., and Kessler, W.D. (1994) The groundfish resources of the Aleutian Islands region and southern Bering Sea 1980, 1983, and 1986. 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Class Chondrichthyes – Cartilaginous Fishes. Class Holocephali – Chimaeras. Class Osteichthyes – Bony Fishes. P. 7-69 In: R.S. Moiseev and A.M. Tokranov (Eds.). Catalogue of vertebrates of Kamchatka and adjacent waters. Petropavlovsk-Kamchatsky, Kamchatskii Pechatnyi Dvor (In Russian). Shuntov, V.P. (1966) Some peculiarities of vertical distribution of Greenland halibut and arrow- toothed flounders in the North Pacific Ocean. Voprosy Ikhtiologii 6, 32-41 (IN Russian). Stabeno, P.J., Shumacher, J.D., and Ohtani, K. (1999) The Physical oceanography of the Bering Sea. P. 1-28 In: (T.R. Loughlin and K. Ohtani (eds.). Dynamics of the Bering Sea. University of Alaska Sea Grant, AK-SG-99-03, Fairbanks, USA. Tokranov, A.M. (1998) Some features of biology of sponge sculpin Thyriscus anoplus (Cottidae) in the Pacific waters off the northern Kuril Islamnds. Voprosy Ikhtiologii 38, 701-703 (In Russian). Tokranov, A.M. (2002) About occurrence of sablefish young Anoplopoma fimbria (Pallass) (Anoplopomatidae) in near Kamchatkan waters. Okeanologiya 42, 124-126 (In Russian). Tokranov, A.M., and Davydov, I.I. (1998) Some biological features of shortraker rockfish Sebastes borealis (Scorpaenidae) in the Pacific waters off Kamchatka and in the western Bering Sea. 2. Size-age composition. Journal of Ichthyology 38, 42-46. Tokranov, A.M., and Vinnikov, A.V. (2000) Capture of rex sole Glyptocephalus zachirus Lockington (Pleuronectidae) in waters of the southeastern Kamchatka. Voprosy Ikhtiologii 40, 397-398 (In Russian). Tokranov, A.M. and Orlov, A.M. (2001a) Distribution and some biological features of the new for the Russia fauna species longfin Irish lord Hemilepidotus zapus Gilbert et Burke, 1912 (Cottidae) in the Pacific Ocean waters of the northern Kuril Islands. P. 236-237 In: Biological Grounding of the Sustainable Development of the Coastal Marine Ecosystems. Abstracts of the presentations of the International Conference, Murmansk, April 25-28, 2001. Apatity, Kola Science Center (In Russian). Tokranov, A.M., and Orlov, A.M. (2001b) Some biological features of rare liparid species (Liparidae) in the Pacific waters of northern Kuril Islands and southeastern Kamchatka. P. 187-190 In: S.G. Korostelev et al. (Eds.). Conservation of Biodiversity of Kamchatka and Coastal Waters. Materials of the II Scientific Conference, Petropavlovsk-Kamchatsky, April 9-10, 2001. Petropavlovsk-Kamchatsky, Kamshat (In Russian). Tokranov, A.M., and Orlov, A.M. (2002) Some problems of biology of two rare species of sculpins (Cottidae) in the Pacific waters of the northern Kuril Islands. P. 239-242 In: Conservation of biodiversity of Kamchatka and coastal waters. Materials of the III Scientific Conference. Petropavlovsk-Kamchatsky, November 27-28, 2002. Petropavlovsk-Kamchatsky, Kamchatpress. Tuponogov, V.N., and Kodolov, L.S. (2001) Sablefish. 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65 S I B E R I A BERING ALASKA 60 SEA A K T A H C 55 M A SEA K Aleutian Islands OF 50 OKHOTSK P A C I F I C O C E A N

ds lan 45 Is ril Ku

150 160 170 180 1907 12600 Figure 1. Scheme of distribution of sablefish, Pacific halibut, arrowtooth flounder, rex sole, and dusky rockfish from eastern to western Bering Sea via active migrations and range extension of adults or via transfer of pelagic fry by currents. 65 directions of currents nursery areas reproduction areas SIBERIA BERING SEA ALASKA 52.8 60 63.9 57.6 46.0

A 63.3 K T A H C 55 M A 47.9 62.5 K 54.8 49.5 Mean length, cm: 41.2 - bottom trawl P A C I F I C O C E A N 70.2 - long-line 50 150 160 170 180 190 200 210

Figure 2. Hypothetic scheme of migrations of shortraker rockfish in the Bering Sea.

60

SEA KAMCHATKA 55 OF OKHOTSK

P A C I F I C O C E A N 50 s nd la Is il ur K

45 150 155 160 165

Figure 3. Map of capture localities of arrowtooth flounder (red asterisks) off the Kurils and Kamchatka in 1992-2002. KAMCHATKA 52 SEA OF OKHOTSK 51

50 PACIFIC

OCEAN 49

48

154 155 156 157 158

Figure 4. Map of capture localities of northern rockfish (red asterisks) off the Kurils and Kamchatka in 1992-2002. 65 S I B E R I A

60

A K T A BERING SEA H SEA C 55 M OF A K OKHOTSK Aleu tian Isla nds 50

P A C I F I C O C E A N 45 150 160 170

Figure 5. Map of capture localities of dusky rockfish (red asterisks) in the northwestern Pacific in 1993-2000. 65 S I B E R I A

60

A K T A SEA H 55 C OF M OKHOTSK A K P A C I F I C O C E A N s nd 50 la Is il ur K

45

150 155 160 165 170

Figure 6. Map of capture localities of rex sole (red asterisks) off the Kurils and Kamchatka in 1998- 2001. 60

A K T SEA A H OF C 55 M OKHOTSK A K

P A C I F I C O C E A N s 50 nd la Is il ur K

150 155 160 165

Figure 7. Map of capture localities of sablefish yearlings (red asterisks) off the Kurils and Kamchatka in 1987-1998. N 65 S I B E R I A

60

A B E R I N G K T A H C M 55 A S E A K SEA Aleutian Islands OF 50 OKHOTSK ds P A C I F I C O C E A N lan Is ril Ku 45

E 150 160 170 180 1790

Figure 8. Hypothetic scheme of range extension of dusky and northern rockfishes, rex sole, and arrowtooth flounder from the Aleutians to Kurils. S I B E R I A

60 B E R I N G S E A

50 P A C I F I C O C E A N

150 160 170 180 190

Figure 9. Map of known capture localities of scaled sculpin (red asterisks) off the Aleutians and Kurils. 60 B E R I N G S E A 55

50 P A C I F I C O C E A N

160 170 180 190 200 Figure 10. Map of known capture localities of longfin Irish lord in the southern Bering Sea and off the Aleutians and Kurils (blue rectangles – larvae, red asterisks – adults). 60 B E R I N G S E A 55 SEA OF OKHOTSK 50 P A C I F I C O C E A N 45 150 160 170 180

Figure 11. Map of known capture localities of blacktip snailfish (red asterisks) off the Aleutians and Kurils. 65 S I B E R I A

60 B E R I N G S E A 55 SEA OF OKHOTSK P A C I F I C 50 O C E A N

45 150 160 170 180

Figure 12. Map of known capture localities of roughskin sculpin (red asterisks) off the Aleutians and Kurils. 65 S I B E R I A 60 B E R I N G S E A 55 SEA OF OKHOTSK 50 P A C I F I C O C E A N 45 150 160 170 180 190

Figure 13. Map of known capture localities of sponge sculpin (red asterisks) off the Aleutians and Kurils. N 65 S I B E R I A

60 B E R I N G

A K T SEA A H S E A OF C M 55 A OKHOTSK K nds an Isla Aleuti 50 ds lan y r e Is i c G ril r c t Ku u b a n S t e r 45 W e s P A C I F I C O C E A N

E 150 160 170 180 1907

Figure 14. Hypothetic scheme of transfer of blacktip snailfish, longfin Irish lord, and scaled, roughskin and sponge sculpins fry from Kurils to the Aleutians by Western Subarctic Gyre waters.