scholarly journals Feeding of smoothtongue Leuroglossus schmidti in the Bering, Okhotsk Seas and adjacent waters of the Pacific Ocean

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 %.

2014 ◽  
Vol 176 (1) ◽  
pp. 210-215
Author(s):  
Alexander Ya. Efimkin

Feeding habits of adult sea bream are considered on the samples collected in the North Pacific and Bering Sea in the last several years. This species is a predator with the diet highly dependent on its habitat and composition of prey (small-sized fish and squids). It has two or three peaks of consumption daily, which change seasonally and year-to-year; anyway, the morning (3-6 a.m.) is usually the time of the lowest consumption, at least in summer and autumn, and the daytime is the normal time for feeding. The sea bream does not eat zooplankton usually, but Euphausia pacifica was a significant portion of its diet (34 %) in the southern part of surveyed area in the summer of 2009, possibly because of high concentrations of euphausiids in that area. Daily ration of adult sea bream is 2.5-3.5 % of its body weight.


1973 ◽  
Vol 30 (12) ◽  
pp. 2373-2385 ◽  
Author(s):  
A. T. Pruter

Fisheries for bottomfish in the Bering Sea are largely a post-second world war development, with landings having increased from 13,000 metric tons in 1954 to an estimated 2 million metric tons in 1971. Most of the harvest is off Alaska in the southeastern sector of the Bering Sea, where conditions are most favorable for development of resources and fisheries. In 1970 and 1971, Japan accounted for approximately 84% and the USSR 15% of the combined harvest by all nations. South Korea, United States, and Canada took the remaining 1% of the harvest. Initial target of the fisheries of Japan and USSR was yellowfin sole. Yields of yellowfin sole were not sustained and Japan shifted attention to Alaska pollock. Production of Alaska pollock in 1970 from the North Pacific (about half is from the Bering Sea) was tied with Atlantic cod for second place in worldwide landings of a single species.Analysis of condition of resources is handicapped by unavailability of adequate statistics for earlier years of the fishery. Even for those participants who provided detailed statistics, information is usually lacking on quantities offish discarded, and changes in fishing gear and fishing tactics that need to be corrected for in assessing the condition of stocks. There is no institutional mechanism for Bering Sea or the North Pacific that makes it mandatory for all nations to provide common and comprehensive statistics on their fisheries and to undertake joint management.Consideration of available data suggests that the pulse nature of the Bering Sea fisheries resulted in the depletion of several important resources. Yellowfin sole were overfished during the early period of the fishery. Although the picture is far from clear for other species, the Pacific Ocean perch, blackcod, and shrimp resources also appear to have been overfished at least on certain important grounds within the Bering Sea. The chronology of Japan’s fishery for herring suggests the initial exploitation of the stock in the western Bering Sea off Asia may have been intense enough to deplete that resource. Although there is yet no indication of depletion of Alaska pollock, the great increase in harvest of that species, coupled with reliance on a few year classes to support the fishery, should serve as a warning against further uncontrolled increases in fishing.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fedor S. Sharko ◽  
Eugenia S. Boulygina ◽  
Svetlana V. Tsygankova ◽  
Natalia V. Slobodova ◽  
Dmitry A. Alekseev ◽  
...  

AbstractAnthropogenic activity is the top factor directly related to the extinction of several animal species. The last Steller’s sea cow (Hydrodamalis gigas) population on the Commander Islands (Russia) was wiped out in the second half of the 18th century due to sailors and fur traders hunting it for the meat and fat. However, new data suggests that the extinction process of this species began much earlier. Here, we present a nuclear de novo assembled genome of H. gigas with a 25.4× depth coverage. Our results demonstrate that the heterozygosity of the last population of this animal is low and comparable to the last woolly mammoth population that inhabited Wrangel Island 4000 years ago. Besides, as a matter of consideration, our findings also demonstrate that the extinction of this marine mammal starts along the North Pacific coastal line much earlier than the first Paleolithic humans arrived in the Bering sea region.


Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 339
Author(s):  
Francisco Omar López-Fuerte ◽  
David Alfaro Siqueiros Beltrones ◽  
María del Carmen Altamirano-Cerecedo

A taxonomic analysis of diatoms found on Phyllodictyon pulcherrimum yielded a total of 244 diatom taxa (all illustrated) within 27 orders, 45 families, and 86 genera. The Taxa were briefly documented in a list including identification references and morphometric data. Thirty-eight of the taxa identified at the species and infraspecific levels represent new records for the coasts of Mexico. Seven were recorded for the first time on the American continent: Auricula flabelliformis, A. pulchra, Campylodiscus scalaris, Coscinodiscus mesoleius, Dimeregramma fulvum, Navicula palpebralis var. angulosa, and Seminavis barbarae, and one, Nitzschia fusiformis, for the Pacific Ocean. This is the second record of the chlorophyte P. pulcherrimum in the north Pacific and the third for Mexican waters. The results confirm that surveying rare macroalgae species as hosts for epiphytic diatoms provides opportunities to seek new records of diatom taxa, or even new taxa, in regions around the world.


2009 ◽  
Vol 75 (2) ◽  
pp. 359-367 ◽  
Author(s):  
Shogo Moriya ◽  
Shunpei Sato ◽  
Moongeun Yoon ◽  
Tomonori Azumaya ◽  
Shigehiko Urawa ◽  
...  

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