Subject: ABSTRACT: Northeast US cetaceans and fish stocks (fwd)

Michael Williamson (pita@whale.simmons.edu)
Sat, 21 Sep 1996 14:12:03 -0400 (EDT)

---------- Forwarded message ----------
Date: Fri, 20 Sep 1996 12:51:18 -0400
From: Robert Kenney <rkenney@gsosun1.gso.uri.edu>
To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET>
Subject: ABSTRACT: Northeast US cetaceans and fish stocks


Kenney, R.D., P.M. Payne, D.W. Heinemann, and H.E. Winn.  1996.  Shifts in
     Northeast Shelf cetacean distributions relative to trends in Gulf of
     Maine/Georges Bank finfish abundance.  Pp. 169-196 in: K. Sherman,
     N.A. Jaworski, and T.J. Smayda, eds.  The Northeast Shelf Ecosystem:
     Assessment, Sustainability, and Management.  Blackwell Science,
     Boston, MA.

     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 of herring stocks, despite the increased abundance of sand lance,
and that the white-sided dolphin replaced the white-beaked dolphin after
the increase in sand lance densities.  During the 1980s, the distribution
of harbor porpoise also shifted away from Georges Bank waters.  We suggest
that harbor porpoise shifted their distribution inshore after the complete
collapse of the Georges Bank herring stock by 1980.  This resulted in
increased harbor porpoise density in coastal and nearshore Gulf of Maine
waters, with a subsequent increase in incidental take in the Gulf of Maine
bottom-gillnet fishery.