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Fishery Bulletin 107(3) 
Table 1 
Summary comparison of numbers, sex, and stomach contents of 34 stranded vs. 28 net-caught Atlantic white-sided dolphins 
(Lagenorhynchus acutus ) collected in the western North Atlantic Ocean off the coast of New England, between 1991 and 2006; 
and seasonality of the net-caught individuals. Total net-caught includes two calves with empty stomachs; seasonal net-caught 
excludes the two calves; S. of Georges = South of Georges Bank. Nontrace = whole prey. 
Seasonal net-caught 
Strandings 
Total net-caught 
Winter 
Summer 
S. of Georges 
Number of dolphins 
34 
28 
22 
3 
1 
Depth where captured (m), mean (range) 
0 
189.8(55-503) 
186.9(71-265) 
107.0 (55-187) 
503 
Number of males 
22 
9 
9 
0 
0 
Length of males (cm), mean (range) 
227(156-280) 
208 (173-260) 
208 (173-260) 
0 
0 
Adult males (>230cm) 
10 
2 
2 
0 
0 
Number of females 
12 
16 
12 
3 
1 
Length of females (cm), mean (range) 
205(168-219) 
199 (161-253) 
203(171-253) 
178(161-203) 
252 
Adult females (>200cm) 
10 
6 
4 
1 
1 
Number unsexed 
Number of stomachs containing food 
0 
22 (65%) 
3 
25 (89%) 
1 
20 (91%) 
3 (100%) 
1 ( 100%) 
Number of empty stomachs 
12 (35%) 
3 (11%) 
2 (9%) 
0 
0 
Number of otoliths 
856 
10287 
2157 
287 
7843 
unidentified 
231 
54 
51 
2 
1 
Number of fish species 
8 
21 
17 
6 
7 
Number of cephalopod beaks 
34 
535 
519 
11 
5 
Number of cephalopod species 
3 
3 
3 
2 
1 
Number of identified prey 
Nontrace fishes 
0 
50 
35 
15 
0 
Near nontrace fishes (skulls) 
7 
56 
38 
4 
14 
Total fishes 
332 
5179 
1120 
135 
3924 
Nontrace cephalopods 
0 
2 
0 
2 
0 
Near nontrace cephalopods 
0 
1 
0 
1 
0 
Total cephalopods 
20 
282 
274 
4 
4 
and size (length, weight) of prey. Two net-caught dol- 
phins examined and subsequently eliminated from the 
analysis were one partly decomposed female with a 
mud-filled stomach and thoracic cavity and virtually no 
food in the stomach, and a partially decomposed male 
with an almost empty stomach taken on the continental 
shelf south of Narragansett Bay. 
Stomachs were weighed whole, divided into their 
three components (forestomach, main, and pyloric), 
emptied of contents, and weighed again to determine 
both the size of the stomach and the mass of its con- 
tents. Whole prey (termed “nontrace” prey because 
they were found relatively intact [not in traces]) were 
separated, identified, weighed, and measured directly 
(standard length for fishes and mantle length for cepha- 
lopods); well-digested prey (termed "trace prey" because 
they were found in traces as hard parts, e.g. skull 
bones, otoliths, jaws, prootic bones of clupeids, teeth 
and opercula of bony fishes, toothplates of hagfish, and 
cephalopod beaks and pens) were separated, identi- 
fied, weighed, and original length measurements were 
estimated indirectly (standard length for fishes and 
mantle length for cephalopods). Otoliths were removed 
from skulls of both nontrace and trace fishes and then 
cleaned, dried, and measured. The remaining contents 
were soaked overnight in hot water, if necessary, or 
elutriated directly through a series of sieves to remove 
soft tissue and retain hard parts. All items found were 
identified to the lowest taxonomic level possible (usu- 
ally to species) by using our own reference collection 
and published guides (Campana, 2004; Clarke, 1962, 
1986; Collette and Klein-MacPhee, 2002; Gregory, 1933; 
Harkonen, 1986; Smale et al., 1995; Vecchione, 2002). 
Forestomach contents were then counted and measured 
and used in all further analyses (Table 2). All fish 
hard parts, including bones and otoliths, and hagfish 
toothplates, were stored dried. Cephalopod beaks were 
removed from buccal masses, cleaned, and stored in 
70% ethanol. Crustacean remains and all parasites 
were counted and also stored in 70% ethanol. 
Prey lengths and weights were calculated from otolith 
lengths for fishes, from lower rostral lengths for squids, 
and from lower hood lengths for octopods (Tables 3 and 
4). Calculations of prey size were used to construct the 
