Gray whale feeding on dense ampeliscid amphipod communities near Bamfield, British Columbia

1984 ◽  
Vol 62 (1) ◽  
pp. 41-49 ◽  
Author(s):  
John S. Oliver ◽  
Peter N. Slattery ◽  
Mark A. Silberstein ◽  
Edmund F. O'Connor
Keyword(s):  
Bering Sea ◽  
Benthic Communities ◽  
Gray Whale ◽  
Gray Whales ◽  
Northern Bering Sea ◽  
Amphipod Crustacean ◽  
Different Parts ◽  
Feeding Grounds ◽  
Made In ◽  
The Bering Sea

Gray whales fed on dense populations of ampeliscid amphipods while summering along the west coast of Vancouver Island. These amphipod crustacean communities are ecological analogs of the primary feeding grounds of gray whales in the northern Bering Sea. The same major genera of amphipods dominated the Alaskan and Canadian feeding grounds, including Ampelisca, Photis, Protomedeia, Anonyx, and Orchomene, and comprised 67 to 90% of the number of infaunal crustaceans at the two locations. This is the first documented report of gray whale feeding on benthic infauna south of the Bering Sea. Feeding gray whales observed in Pachena Bay produced an extensive record of feeding excavations in bottom sediments. Excavation patterns suggest that: (i) whales used suction to extract infaunal prey and sediments; (ii) a maximum of six excavations was made in one feeding dive; (iii) excavation size was related to whale size; (iv) small and large whales fed in different parts of the bay; and (v) whales effectively located and worked the densest patches of benthic prey. We estimate that a 6-m whale consumed 116 kg of infaunal prey per 12-h day, and that a 12-m whale consumed 552 kg per 12-h day. Scavenging lysianassid amphipods were attracted to feeding disturbances within seconds and preyed on injured and dislodged infauna. Individual feeding excavations were large, deep valleys in a tube-mat plateau. In addition to the lysianassids, many other infauna undoubtedly colonize these highly modified habitats, resulting in important effects on the structure of benthic communities.

Swarming benthic crustaceans in the Bering and Chukchi seas and their relation to geographic patterns in gray whale feeding

1989 ◽  
Vol 67 (6) ◽  
pp. 1531-1542 ◽  
Author(s):  
Stacy L. Kim ◽  
John S. Oliver
Keyword(s):  
Bering Sea ◽  
Baja California ◽  
Prey Availability ◽  
Chukchi Sea ◽  
Gray Whale ◽  
Life Stages ◽  
Gray Whales ◽  
Feeding Ground ◽  
Geographic Patterns ◽  
Feeding Grounds

Swarming benthic crustaceans were widespread in the Chukchi and Bering seas. Swarms differed in their geographic extent, local biomass, and life stages of swarming individuals and thus in their availability to feeding gray whales (Eschrichtius robustus). Immature amphipods apparently swarmed for dispersal, whereas cumaceans probably swarmed for mating. All life stages of the hyperbenthic mysids occurred above the sea floor. Although the geographic spread of mysid swarms and shrimp communities was much greater than for the amphipod and cumacean swarms, the latter swarmed in denser patches to produce higher local biomass. Crustacean swarms are important in describing the geographic patterns of gray whale feeding from the Chukchi Sea to Baja California, including the primary, secondary, and tertiary feeding grounds. The primary feeding ground is in the southern Chukchi Sea and especially the northern Bering Sea, where gray whales suck infaunal amphipods from fine sand, producing an extensive record of feeding excavations. The primary feeding ground is divided into a relatively deep zone (> 20 m), where tube-dwelling ampeliscid amphipods are the major prey, and a shallow zone (< 20 m), where burrowing pontoporeid amphipods dominate. The secondary feeding ground is in the southern Bering Sea along the eastern Alaska Peninsula and adjacent Alaskan mainland where shrimp and mysids are the major prey. The tertiary feeding ground is at the periphery of the primary and secondary feeding grounds in Alaskan waters and south of the Bering Sea where there is a general decrease in the availability of prey and their use by gray whales from Canada to Baja California. The tertiary prey communities include swarms of amphipods, cumaceans, and mysids as well as infaunal polychaete worms, but mysids are used the most by whales. The primary gray whale feeding ground was much smaller during low sea levels when the extensive Beringian Platform was exposed to air. This shallow shelf is a unique habitat that presently harbors the largest ampeliscid amphipod community in the world. At low sea level, swarming crustaceans like those sampled in the present study may have been equally or more important to gray whales than infaunal prey. These historical changes in prey availability may account for the catholic diet of the gray whale.

Migration and Feeding of the Gray Whale (Eschrichtius gibbosus)

1962 ◽  
Vol 19 (5) ◽  
pp. 815-838 ◽  
Author(s):  
Gordon C. Pike
Keyword(s):  
British Columbia ◽  
Bering Sea ◽  
Chukchi Sea ◽  
Close Contact ◽  
Gulf Of Alaska ◽  
Bering Strait ◽  
Visual Contact ◽  
Gray Whales ◽  
Baleen Whales ◽  
The Bering Sea

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.

scholarly journals Why does the pollock (Theragra chalcogramma) abundance change

2016 ◽  
Vol 185 (2) ◽  
pp. 31-48
Author(s):  
Vyacheslav P. Shuntov
Keyword(s):  
Bering Sea ◽  
Food Supply ◽  
Global Changes ◽  
Winter Mortality ◽  
Migration Timing ◽  
Northern Bering Sea ◽  
Class Strength ◽  
Strength Dependence ◽  
The Bering Sea

Some common ideas about environmental factors that determine the patterns of migration (including timing) and stock dynamics of walleye pollock are critically analyzed with particular attention to the Bering Sea. There is shown that the conception of the migration timing dependence on food supply in the northern Bering Sea does not represent the real facts, as well as the conception of year-class strength dependence on winter mortality of fingerlings determined by food supply, especially in conditions of its deficiency. Periodicity of the pollock stocks dynamics associated with global changes of climatic and oceanographic factors is also called in question. Role of provincial factors in dynamics of the pollock populations is discussed and emphasized.

Middle Pleistocene Mollusks from St. Lawrence Island and their Significance for the Paleo-Oceanography of the Bering Sea

1972 ◽  
Vol 2 (02) ◽  
pp. 119-134 ◽  
Author(s):  
David M. Hopkins ◽  
Robert W. Rowland ◽  
William W. Patton
Keyword(s):  
Bering Sea ◽  
Middle Pleistocene ◽  
Pacific Water ◽  
Arctic Water ◽  
Ice Cap ◽  
Northern Bering Sea ◽  
Eastern Bering Sea ◽  
Flow Through ◽  
The Bering Sea ◽  
Arctic Fauna

Drift, evidently of Illinoian age, was deposited on St. Lawrence Island at the margin of an ice cap that covered the highlands of the Chukotka Peninsula of Siberia and spread far eastward on the continental shelf of northern Bering Sea. Underlying the drift on the northwestward part of the island are mollusk-bearing beds deposited during the Kotzebuan Transgression. A comparison of mollusk faunas from St. Lawrence Island, Chukotka Peninsula, and Kotzebue Sound suggests that the present northward flow through Bering and Anadyr Straits was reversed during the Kotzebuan Transgression. Cold arctic water penetrated southward and southwestward bringing an arctic fauna to the Gulf of Anadyr. Warmer Pacific water probably entered eastern Bering Sea, passed eastward and northeastward around eastern and northern St. Lawrence Island, and then became entrained in the southward currents that passed through Anadyr Strait.

Gray whales and the structure of the Bering Sea benthos

Oecologia ◽  
1983 ◽  
Vol 59 (2-3) ◽  
pp. 224-225 ◽  
Author(s):  
M. K. Nerini ◽  
J. S. Oliver
Keyword(s):  
Bering Sea ◽  
Gray Whales ◽  
The Bering Sea

scholarly journals Do Gray Whales Count Calories? Comparing Energetic Values of Gray Whale Prey Across Two Different Feeding Grounds in the Eastern North Pacific

2021 ◽  
Vol 8 ◽  
Author(s):  
Lisa Hildebrand ◽  
Kim S. Bernard ◽  
Leigh G. Torres
Keyword(s):  
North Pacific ◽  
Prey Availability ◽  
The Arctic ◽  
Caloric Content ◽  
Amphipod Species ◽  
Gray Whale ◽  
Dungeness Crab ◽  
Gray Whales ◽  
The Mean ◽  
Feeding Grounds

Predators must consume enough prey to support costly events, such as reproduction. Meeting high energetic requirements is particularly challenging for migrating baleen whales as their feeding seasons are typically restricted to a limited temporal window and marine prey are notoriously patchy. We assessed the energetic value of the six most common nearshore zooplankton species collected within the Oregon, United States range of the Pacific Coast Feeding Group (PCFG) gray whale (Eschrichtius robustus) feeding grounds, and compared these results to the energetic value of the predominant amphipod species fed on by Eastern North Pacific (ENP) gray whales in the Arctic. Energetic values of Oregon zooplankton differed significantly between species (Kruskal–Wallis χ2 = 123.38, df = 5, p &lt; 0.0001), with Dungeness crab (Cancer magister) megalopae displaying the highest mean caloric content of all tested species (4.21 ± 1.27 kJ g– 1). This value, as well as the mean energetic value of the mysid Neomysis rayii (2.42 ± 1.06 kJ g– 1), are higher than the mean caloric content of Ampelisca macrocephala, the predominant Arctic amphipod. Extrapolations of these results to daily energetic requirements of gray whales indicate that lactating and pregnant gray whales feeding in the PCFG range would require between 0.7–1.03 and 0.22–0.33 metric tons of prey less per day if they fed on Dungeness crab megalopae or N. rayii, respectively, than a whale feeding on A. macrocephala in the Arctic. Yet, these results do not account for differences in availability of these prey species to foraging gray whales. We therefore suggest that other factors, such as prey density, energetic costs of feeding, or natal philopatry and foraging site fidelity play a role in the differences in population sizes between the PCFG and ENP gray whales. Climate change is implicated in causing reduced body condition and increased mortality of both PCFG and ENP gray whales due to decreased prey availability and abundance. Therefore, improved understanding of prey dynamics in response to environmental variability in both regions is critical.

Feeding of ribbon seals (Phoca fasciata) in the Bering Sea in spring

1980 ◽  
Vol 58 (9) ◽  
pp. 1601-1607 ◽  
Author(s):  
Kathryn J. Frost ◽  
Lloyd F. Lowry
Keyword(s):  
Bering Sea ◽  
Arctic Cod ◽  
Main Prey ◽  
Northern Bering Sea ◽  
South Central ◽  
Fresh Food ◽  
Northern Areas ◽  
Pack Ice ◽  
Fish Otoliths ◽  
The Bering Sea

Digestive tracts of 61 ribbon seals (Phoca fasciata) collected in the seasonal pack ice of the Bering Sea during March to June 1976–1979 were examined. Very little fresh food was found in stomachs; however, hard parts of prey, particularly fish otoliths, were found in stomachs and (or) intestines of 28 seals. Based on counts of otoliths, the main prey were pollock in south-central and central Bering Sea, and arctic cod in northern Bering Sea. Weights and lengths of fishes consumed by seals were estimated from measurements of otoliths. On the basis of estimated whole weight of prey consumed, eelpout were a major food of these seals in south-central and central Bering Sea. Comparison of the species composition of fishes caught in trawls and eaten by seals suggests that seals in central and northern Bering Sea select for pollock and arctic cod, and against sculpins and capelin. In contrast, in south-central Bering Sea pollock was the most abundant fish in both seals and trawls. Seals were nonselective with regard to size of pollock consumed but appeared to select for large arctic cod. Our data suggest feeding conditions may be more favorable for ribbon seals in south-central Bering Sea than in more northern areas.

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