Sources of variation in diets of harp and hooded seals estimated from quantitative fatty acid signature analysis (QFASA)

摘要: Inter-specific competition for prey is thought to influence the structure of ecological communities and species niche breadth. Harp seals Pagophilus groenlandicus hooded Cystophora cristata are geographically overlapping highly migratory predators in North Atlantic ocean. Hooded known dive deeper longer than harp more closely associated with continental shelf edge deep Quantitative fatty acid (FA) signa- ture analysis (QFASA) was recently developed estimate composition diets by statis- tically comparing FA signatures predator adipose tissue that potential prey. Using QFASA, we estimated (adults, n = 294; juveniles, 232) 115; 38) from pre- post-breeding periods between 1994 2004. We found evidence inter- intra-specific variation diets, diet quality breadth, reflecting different foraging tac- tics. seal were comprised predominantly amphipods, Arctic cod, capelin, herring, sand lance redfish. composed primarily argentine, euphausiids Relative other species, consumed twice propor- tion while 3 times proportion redfish; percentages capelin similar. QFASA provided new importance amphipods both pronounced differences proportions pelagic forage fish demographic groups.