This paper is not subject to U.S. copyright. The definitive version was published in Fishery Bulletin 107 (2009): 384–394.Although the Atlantic
white-sided dolphin (Lagenorhynchus
acutus) is one of the most common
dolphins off New England, little has
been documented about its diet in
the western North Atlantic Ocean.
Current federal protection of marine
mammals limits the supply of animals
for investigation to those incidentally
caught in the nets of commercial fishermen
with observers aboard. Stomachs
of 62 L. acutus were examined; of
these 62 individuals, 28 of them were
caught by net and 34 were animals
stranded on Cape Cod. Most of the
net-caught L. acutus were from the
deeper waters of the Gulf of Maine. A
single stomach was from the continental
slope south of Georges Bank. At
least twenty-six fish species and three
cephalopod species were eaten. The
predominant prey were silver hake
(Merluccius bilinearis), spoonarm
octopus (Bathypolypus bairdii), and
haddock (Melanogrammus aeglefinus).
The stomach from a net-caught L.
acutus on the continental slope contained
7750 otoliths of the Madeira
lanternfish (Ceratoscopelus maderensis).
Sand lances (Ammodytes spp.)
were the most abundant (541 otoliths)
species in the stomachs of stranded
L. acutus. Seasonal variation in diet
was indicated; pelagic Atlantic herring
(Clupea harengus) was the most
important prey in summer, but was
rare in winter. The average length of
fish prey was approximately 200 mm,
and the average mantle length of
cephalopod prey was approximately
50 mm