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Marine mammals can be used as indicators of environmental productivity because they must feed efficiently and therefore aggregate where prey is plentiful. Three species of cetaceans, bowhead whales (Balaena mysticetus), gray whales (Eschrichtius robustus) and white whales (Delphinapterus leucas) mig...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.581.6891 http://journal.nafo.int/J22/Moore.pdf |
| Summary: | Marine mammals can be used as indicators of environmental productivity because they must feed efficiently and therefore aggregate where prey is plentiful. Three species of cetaceans, bowhead whales (Balaena mysticetus), gray whales (Eschrichtius robustus) and white whales (Delphinapterus leucas) migrate to the Alaskan arctic each year to feed. These species have distinctly different feeding modes and forage at dissimilar trophic levels. Bowhead whales filter zooplankton from the water column, gray whales siphon infaunal crustaceans from the benthos and white whales catch a variety of nekton includ-ing crustaceans, cephalopods and fishes. Line transect aerial surveys were conducted over the Alaskan Chukchi and Beaufort seas each late summer and autumn 1982–91. The resulting database, consisting of 634 flights, was post-stratified by survey type and sea state (Beaufort ≤04) to provide a data-base of cetacean sightings made along random transects during good survey conditions. Sightings made during connect and search legs of the survey, and in rough seas were ex-cluded. Post-stratification resulted in a cumulative (1982–91) database of 276 754 transect- |
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