Shifts in Northeast shelf cetacean distributions relative to trends in Gulf of Maine/Georges Bank finfish abundance

摘要: A significant decrease in the standing stocks of Georges Bank/Gulf of Maine herring and mackerel during the 1960s precipitated a series of ecological responses by the finfish and cetacean fauna of the Northeast Shelf. A population explosion of sand lance followed the decline in the commercial pelagic fish stocks in these regions. Humpback whale distributions shifted from the northern Gulf of Maine to the southwestern Gulf in the late 1970s and early 1980s, reflecting a shift in diet from herring to sand lance. After a crash in Massachusetts Bay sand lance populations in 1986, piscivorous humpback and fin whales were largely replaced by planktivorous right and sei whales. The abundance of white-sided dolphins increased in the Gulf of Maine during the mid-1970s concurrent with a decline in the abundance of white-beaked dolphins. We hypothesize that white-beaked dolphin densities decreased after the decline …