Cox et at: Documenting bycatch of Phocoena phocoena from stranded carcasses 
729 
were then stored frozen and examined at the 
Smithsonian Institution (SI) during necropsy work- 
shops in May 1994, November 1995, and October 
1996. In all but three specimens, assessments made 
by stranding network personnel on the beach were 
compared with independent assessments made at the 
SI. The determination of entanglement was conser- 
vative; an animal was scored as having been en- 
tangled only when external lacerations or impres- 
sions from net material or when mutilation consis- 
tent with entanglement was clearly present. If a car- 
cass was too decomposed to determine cause of death 
definitively, or if skin was missing from a large pro- 
portion of the appendages, it was scored as “CBD” 
(could not be determined). Read and Murray 3 deter- 
mined that all porpoises killed in sink gill nets and 
retrieved by observers exhibited external net marks. 
Thus, if a carcass could be assessed, but was scored 
as not having died of entanglement, the animal was 
assumed to have died of natural causes. Investiga- 
tors attempted to identify the net type (i.e. monofila- 
ment or multifilament ) responsible for the entangle- 
ment. The condition of the carcass on the SI scale, in 
which code 1 = alive, code 2 = dead but fresh, code 3 
= moderately decomposed, code 4 = severely decom- 
posed, and code 5 = skeletal remains was noted 
(Geraci and Lounsbury, 1993). 
Standard morphometric data (Norris, 1961) were 
collected and body condition was evaluated as robust 
(convex epaxial surface and no “neck” evident) or 
emaciated (concave epaxial surface and “neck” evi- 
dent) (Kastelein et al., 1997). Testis size and the pres- 
ence or absence of ovarian scars (Read and Hohn, 
1995) were used to determine the sexual maturity of 
individuals. 
A chi-square test (Sokal and Rohlf, 1981) was used 
to determine whether there was a difference in car- 
cass condition (SI codes 2 and 3) between entangled 
and nonentangled animals. To determine if there was 
a difference in body condition (robust or emaciated) 
in entangled and nonentangled animals, a G-test 
with an adjusted G-value for William’s correction 
(Sokal and Rohlf, 1981) was conducted. Two G tests 
were also used (Sokal and Rohlf, 1981): the first to 
compare the mean standard lengths of entangled and 
nonentangled stranded animals; the second to com- 
pare the mean standard lengths of stranded en- 
tangled animals and 10 nonstranded entangled ani- 
mals. The standard lengths of the latter set of por- 
poises were collected by observers working on gill- 
net vessels off the coasts of Maryland and North 
Carolina during 1995 and 1996. Only those animals 
3 Read, A, and K. Murray. 135 Duke Marine Lab Rd., Beaufort, 
NC 28516. Unpubl. data. 
for which we were able to assess evidence of fisher- 
ies interaction were included in the statistical analy- 
ses; those scored as CBD were excluded from these 
analyses. Mean standard lengths are reported with 
associated standard deviations. 
ResuJts 
Characterization of strandings 
We examined 107 harbor porpoise carcasses (Table 
1; Fig. 2). We are aware of 17 additional harbor por- 
poise strandings that occurred between 1994 and 
1996 in the Mid-Atlantic but did not include these 
strandings in our analysis. Fifteen of these 17 car- 
casses were not examined according to our protocol, 
and data discrepancies could not be resolved for two 
others. Of the 107 porpoise carcasses that we in- 
cluded, 104 were examined independently both on 
the beach and at SI workshops. The remaining three 
carcasses were examined only on the beach; however, 
excellent photo-documentation allowed researchers 
at the SI to confirm the assessments for these three 
carcasses that had been made on the beach by strand- 
ing network personnel. 
All harbor porpoise strandings occurred between 
January and May, with a peak between the months 
of March and May (Table 2). Fifty-five animals were 
male, 51 female; the sex of one was unidentifiable 
TabUe 1 
Summary of harbor porpoises ( Phocoena phocoena) 
stranded along the Mid-Atlantic coast (by year and state) 
and evidence of entanglement. Yes = evidence of fisheries 
interaction; No = no evidence of fisheries interaction; CBD = 
evidence of fisheries interaction could not be determined 
owing to advanced decomposition of carcass. 
Year 
State 
Total 
Yes 
No 
CBD 
1994 
NC 
5 
0 
2 
3 
MD 
9 
4 
2 
3 
VA 
39 
13 
3 
23 
Total 
53 
17 
7 
29 
1995 
NC 
7 
1 
3 
3 
MD 
2 
1 
1 
0 
VA 
15 
0 
2 
13 
Total 
24 
2 
6 
16 
1996 
NC 
11 
2 
2 
7 
MD 
3 
1 
0 
2 
VA 
16 
3 
0 
13 
Total 
30 
6 
2 
22 
Total 
107 
25 
15 
67 
