Trends in Stranding and By-Catch Rates of Gray and Harbor Seals along the Northeastern Coast of the United States: Evidence of Divergence in the Abundance of Two Sympatric Phocid Species?

摘要: Harbor seals and gray are sympatric phocid pinnipeds found in coastal waters of the temperate sub-Arctic North Atlantic. In Northwest Atlantic, both species were depleted through a combination subsistence hunts government supported bounties, now re-occupying substantial portions their original ranges. While appear to have recovered during past 2 decades, our understanding population dynamics US is incomplete. Here we describe trends stranding bycatch rates harbor East United States (NEUS) over 16 years an exploratory curve-fitting exercise structural break-point analysis. Variability seal strandings Southern New England Northeast Sink Gillnet Fishery best described by fitting positive exponential linear models, exhibited increase as high 22%. contrast, neither nor models fit oscillation study period. However, breakpoint Chow test revealed that Cape Cod, Massachusetts region increased 1990s then started declining early mid-2000s. Our analysis indicates ongoing variation natural anthropogenic mortality NEUS not synchronous, likely represents diverging abundance these they assume new roles marine ecosystems region.