384 
Abstract — 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 fish- 
ermen with observers aboard. Stom- 
achs 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 continen- 
tal 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 con- 
tained 7750 otoliths of the Madeira 
lanternfish ( Ceratoscopelus maderen- 
sis). 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 her- 
ring ( 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. 
Manuscript submitted 18 September 2008. 
Manuscript accepted 5 May 2009. 
Fish. Bull. 107:384-394(2009). 
The views and opinions expressed 
or implied in this article are those 
of the author and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Food habits of Atlantic white-sided 
dolphins ( Lagenorhynchus acutus) 
off the coast of New England 
James E. Craddock (contact author ) 1 
Pamela T. Polloni 1 
Brett Hayward 2 
Frederick Wenzel 3 
Email address for contact author: jcraddock@whoi.edu 
1 Biology Department 
Woods Hole Oceanographic Institution 
Woods Hole, Massachusetts 02543 
2 Integrated Statistics, Inc. 
16 Sumner St. 
Woods Hole, Massachusetts 02543 
3 Protected Species Branch 
Northeast Fisheries Science Center 
National Marine Fisheries Service 
166 Water Street, Woods Hole, Massachusetts 02543 
The Atlantic white-sided dolphin 
(Lagenorhynchus acutus) is restricted 
to the temperate and subpolar North 
Atlantic Ocean, ranging from west 
Greenland (approximately 64°N) to 
North Carolina (about 35°N) in the 
western North Atlantic, and from 
Norway to the Bay of Biscay in the 
eastern North Atlantic (Leopold and 
Couperus, 1995). There are thought 
to be three populations in the western 
North Atlantic — the Gulf of Maine, 
Gulf of St. Lawrence, and Labrador 
Sea populations (Palka et al., 1997). 
Seasonal shifts in the Gulf of Maine 
population have been reported; high- 
est numbers are found in summer and 
fall and lowest numbers in winter 
(Northridge et al., 1997; Palka et al., 
1997). Most of our animals, however, 
were obtained during the winter. 
This study is the first detailed 
analysis of the food habits of the 
Atlantic white-sided dolphin in the 
western North Atlantic Ocean, here- 
after referred to as L. acutus rather 
than the more cumbersome Atlantic 
white-sided dolphin. Previously, only 
three live-caught specimens from off 
New England have been examined 
for stomach contents and reported in 
the literature. A single specimen col- 
lected in 1954 (Schevill, 1956) and a 
second collected in 1976, likely a dis- 
carded incidental take from a gillnet 
set near Jeffreys Ledge (Katona et 
al., 1978), were taken in summer and 
contained the same species of fish and 
squid. These records indicated that 
Atlantic herring ( Clupea harengus), 
silver hake (Merluccius bilinearis), 
and northern shortfin squid (Illex il- 
lecebrosus) could be significant com- 
ponents of the diet. A single animal 
driven ashore in Trinity Bay, New- 
foundland, also contained Atlantic 
herring and northern shortfin squid 
(Sergeant and Fisher, 1957). 
Other observations have reported 
a few more prey species for L. acu- 
tus. Stomachs of 14 of 40 stranded L. 
acutus examined from Cobscook Bay, 
Maine, contained one silver hake, 
nine shortfin squid, five rainbow smelt 
( Osmerus mordax ), and fragments of 
unidentified decapod shrimp (St. Au- 
bin and Geraci, 1979; Sergeant et al., 
1980). Katona et al. (1978) reported 
probable feeding on sand lances ( Am- 
modytes spp.) by L. acutus associated 
with feeding humpback (Megaptera 
novaeangliae ) and fin whales (Balae- 
noptera physalus). The only L. acutus 
feeding incident recorded was on De- 
cember 20, 1997, on Stellwagen Bank, 
southwestern Gulf of Maine, when a 
