scholarly journals Abundance and ecology of Myctophidae fishes in the Gulf of Alaska in winter season

2021 ◽  
Vol 201 (2) ◽  
pp. 292-312
Author(s):  
V. I. Radchenko ◽  
A. N. Kanzeparova ◽  
A. A. Somov ◽  
I. V. Grigorov

Distribution and abundance of myctophid fish species in the upper epipelagic layer are analyzed based on results of surveys in the Gulf of Alaska in winters of 2019 and 2020. A common myctophid community driven by blue lanternfish Tarletonbeania crenularis was revealed that occupied likely the entire eastern part of the Subarctic Front zone eastward from 150ºW. Abundance and biomass of four mass myctophid species were generally comparable between the northeastern and northwestern Pacific. Small-sized juveniles prevailed among northern lampfish Stenobrachius leucopsarus, which were likely transported by the Subarctic Current and could be recruited to the Bering Sea stock. Patterns of daily vertical migrations are discussed for the mass myctophid species. New observations confirm general understandings on the myctophid species input to functioning of fish community.

1996 ◽  
Vol 46 (3) ◽  
pp. 230-250 ◽  
Author(s):  
Sergei A. Gorbarenko

Stable isotopes, geochemical, lithological, and micropaleontological results from cores from the far northwest (FNW) Pacific and the Okhotsk and Bering seas are used to reconstruct the regional environment for the last glaciation, the deglacial transition, and the Holocene. δ18O records of planktonic foraminifera of the region show two “light” shifts during deglacial time, provoked by the freshening of the surface water and climate warming. These north Pacific terminal events (T1ANP and T1BNP) with ages of 12,500 and 9300 yr B.P., respectively, occur almost simultaneously with two episodes of accelerated glacier melting around the North Atlantic. Along with the isotopic shifts, the CaCO3 content in regional sediments increased abruptly (1A and 1B carbonate peaks), probably due to changes of productivity and pore water chemistry of surface sediments. Organic matter and opal concentration increased during the transition (between T1ANP and T1BNP events) in the sediments of the FNW Pacific and the southern part of the Bering Sea and opal content increased in the Holocene in the Bering and Okhotsk Seas. δ13C records of cores from the Okhotsk and Bering seas and the FNW Pacific do not contradict the hypothesis of increased intermediate water formation in the region during glaciation. During deglaciation, accumulation of the coarse terrigenous component decreased in sediments of the Bering Sea and the FNW Pacific before the T1ANP event, probably as a result of rising sea level and opening of the Bering Strait.


1962 ◽  
Vol 19 (5) ◽  
pp. 815-838 ◽  
Author(s):  
Gordon C. Pike

Observations of gray whales from the coasts of British Columbia, Washington, and Alaska are compared with published accounts in order to re-assess knowledge of migration and feeding of the American herd. Source of material is mainly from lighthouses and lightships.The American herd of gray whales retains close contact with the shore during migration south of Alaska. Off Washington and British Columbia the northward migration begins in February, ends in May, and is at a peak during the first two weeks in April; the southward migration occurs in December and January, and is at a peak in late December. Northward migrants stop occasionally to rest or feed; southward migrants are travelling faster and appear not to stop to rest or feed during December and January. Gray whales seen off British Columbia, sometimes in inside protected waters, from June through October, probably remain in this area throughout the summer and fall months.Available evidence suggests that gray whales retain contact with the coast while circumscribing the Gulf of Alaska, enter the Bering Sea through eastern passages of the Aleutian chain, and approach St. Lawrence Island by way of the shallow eastern part of the Bering Sea. Arriving off the coast of St. Lawrence Island in May and June the herd splits with some parts dispersing along the Koryak coast and some parts continuing northward as the ice retreats through Bering Strait. Gray whales feed in the waters of the Chukchi Sea along the Siberian and Alaskan coasts in July, August and September. Advance of the ice through Bering Strait in October initiates the southern migration for most of the herd. In summering areas, in northern latitudes, gray whales feed in shallow waters on benthic and near-benthic organisms, mostly amphipods.There is no evidence to indicate that gray whales utilize ocean currents or follow the same routes as other baleen whales in their migrations. Visual contact with coastal landmarks appear to aid gray whales in successfully accomplishing the 5000-mile migration between summer feeding grounds in the Bering and Chukchi Seas and winter breeding grounds in Mexico.Reconstruction of the migration from all available data shows that most of the American herd breeds and calves in January and February, migrates northward in March, April and May, feeds from June through October, and migrates southward in November and December.


1982 ◽  
Vol 87 (C8) ◽  
pp. 5785 ◽  
Author(s):  
J. D. Schumacher ◽  
C. A. Pearson ◽  
J. E. Overland

2016 ◽  
Vol 132 ◽  
pp. 227-239 ◽  
Author(s):  
Carolina Parada ◽  
Sarah Hinckley ◽  
John Horne ◽  
Michael Mazur ◽  
Albert Hermann ◽  
...  

1983 ◽  
Vol 61 (1) ◽  
pp. 266-268 ◽  
Author(s):  
G. J. Munger

Of 33 species of fish examined for Anisakis larvae, 12 (36%) were infected. Larvae were identified as Anisakis type I larvae (Oshima 1972) and were found in fish from all localities surveyed: Bristol Bay, Unimak, Chirikof, Chiniak, and Cape St. Elias. The small size and feeding habits of some fish infected suggests that small fishes or very small invertebrates rather than euphausids may be the intermediate hosts for Anisakis type I larvae.


2020 ◽  
Vol 200 ◽  
pp. 38-57
Author(s):  
A. O. Zolotov ◽  
O. G. Zolotov ◽  
Yu. K. Kurbanov

Atka mackerel Pleurogrammus monopterygius is one of the mass species of fam. Hexagrammidae that inhabits the boreal and subarctic waters of the North Pacific and forms two large populations in its western and eastern parts. Reproductive range of the eastern, Aleutian population extends from the Gulf of Alaska, along Aleutian Islands to Commander Islands, with the main spawning grounds at the Aleutians and in the southeastern Bering Sea. From these areas, the fish at early stages of ontogenesis spread widely in system of the Bering Sea currents to the western-southwestern Bering Sea, where the atka mackerel aggregations are formed on the external shelf at prominent capes, as Cape Olyutorsky. Dynamics of the atka mackerel stock in the Olyutorsky-Navarinsky area in 1994–2019 is presented on the base of bottom trawl surveys, fishery statistics, and open NOAA data. After the period of low stock in the middle 1990s, the atka mackerel abundance increased sharply to the maximum in 2006–2008, when the spawning stock in this area was about 9.5 . 103 t and the commercial stock about 14.0 . 103 t. Since that time, trend to decreasing is observed, with the spawning stock 3.6 . 103 t and the commercial stock 5.6 . 103 t in 2013, and recent stabilization at the low level with slight decline continuing. A possible reason of the sharp increase in 2000s could be the intensive transport of the atka mackerel juveniles from the main spawning grounds at Aleutian Islands to the area at Cape Olyutorsky. The catches of atka mackerel in the Olyutorsky-Navarinsky area in 1994–2018 corresponded well with its stock dynamics.


2016 ◽  
Vol 184 (1) ◽  
pp. 150-157
Author(s):  
Alexander Ya. Efimkin

Smoothtongue Leuroglossus schmidti is a small mesopelagic fish species common for subarctic waters. It rises to the upper epipelagic layer at night for feeding and preys mainly on euphausiids, copepods and amphipods. Its mean index of stomach fullness reaches 68 ‱ in the epipelagic layer, but it almost doesn’t feed deeper than 200 m, judging by a little food in the stomach. In the Bering Sea, euphausiids dominate in its diet and the portion of copepods is small. In the ​​Okhotsk Sea, each of these two groups provides a half of the diet. In the North Pacific, the portion of copepods is 63 % on average, euphausiids are the second important prey, and amphipods occur in the diet occasionally. Daily ration of smoothtongue is about 1.4 %.


2021 ◽  
Vol 946 (1) ◽  
pp. 012024
Author(s):  
P D Kuznetsov ◽  
E A Rouvinskaya ◽  
O E Kurkina ◽  
A A Kurkin

Abstract This work is devoted to the study of the regimes of transformation of baroclinic tidal waves under the conditions of the Far Eastern seas within the framework of a fully nonlinear numerical model. Two sections were selected to study the features of wave dynamics – in the Sea of Okhotsk (Sakhalin Island shelf) and in the Bering Sea (near Cape Navarin). On the basis of the performed calculations, regional and seasonal features of the transformation of baroclinic waves and the structure of the flow induced by them were revealed. It is shown that the dynamics in the winter season is less intensive. The rotation effect on the formation of solibore in the studied conditions is analyzed. The obtained estimates of wave amplitudes and velocities are consistent with the published data of field observations in the Sea of Okhotsk. For the Bering Sea, the conditions are shown to be favorable for the generation of intensive internal waves, which indirectly confirms the hypothesis of influence of such waves on the formation of underwater sand dunes.


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