436 
Fishery Bulletin 96(3), 1 998 
tion in the winter and spring is required before we 
can fully assess the ecological relations between har- 
bor porpoises and their prey in this system. We also 
suggest that further investigation of the ecological 
relations among Atlantic herring, groundfish, and 
harbor porpoises may provide information that will 
allow improved understanding of the causes of por- 
poise entanglement in gill nets and that will perhaps 
offer some insight into measures that may mitigate 
this problem. 
Acknowledgments 
We thank fisheries observers from Manomet Obser- 
vatory and gillnet fishermen for their perseverance 
in obtaining these samples. Many colleagues partici- 
pated in porpoise necropsies, including Dave 
Johnston, Heather Koopman, Bill McLellan, Kim- 
berly Murray, Aleksija Neimanis, John Nicolas, Ann 
Pabst, Charley Potter, Butch Rommel, Krystal Tolley, 
and Andrew Westgate. Aleksija Neimanis, Pam 
Polloni, C.J. Sylvester, and Trevor Spradlin sorted 
the contents of numerous stomachs. Amy Williams, 
Gina Reppucci, and Kathryn Bisack located missing 
data for many porpoises. Richard Harbison provided 
the butterfish used to calculate the length and mass 
regressions. Tara Cox prepared Figure 1. Comments 
and criticism from three anonymous reviewers re- 
sulted in a much improved final paper. This work 
was funded by Cooperative Agreement NA57FL0557 
from the Northeast Fisheries Science Center of the 
U.S. National Marine Fisheries Service. 
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