76 
Fishery Bulletin 106(1 ) 
Table 1 
Numbers of bottlenose dolphin ( Tursiops truncatus) recovered ocean-side in North Carolina between November 1997 and April 
2005. Strandings are listed by winter (W) (November-April), summer (S) ( May-October), and all months (T), and categorized 
according to the human interaction (HI) classification: Hl-yes (evidence of human interaction including HI-FI [evidence of fishery 
interaction], and Hi-other [evidence of mutilation, propeller wounds]), Hl-no (no signs of HI), and HI-CBD (human interaction 
could not be determined). For this study, data were not available (n/a) for the 2005 summer season (May-October) and thus totals 
for 2005 are for a partial year, denoted by an asterisk. 
HI -yes 
HI-FI 
Hi-other 
Hl-no 
HI-CBD 
Total 
W S T 
W S T 
W S T 
W S T 
W S 
T 
1998 (Nov 97-Oct 98) 
11 
8 
19 
4 
0 
4 
7 
6 
13 
18 
14 
32 
40 
28 
68 
1999 (Nov 98-Oct 99) 
18 
4 
22 
0 
0 
0 
6 
5 
11 
27 
17 
44 
51 
26 
77 
2000 (Nov 99-Oct 00) 
14 
2 
16 
2 
3 
5 
7 
5 
12 
36 
8 
44 
59 
18 
77 
2001 (Nov 00-Oct 01) 
3 
4 
7 
1 
0 
1 
7 
3 
10 
17 
7 
24 
28 
14 
42 
2002 (Nov 01-Oct 02) 
9 
3 
12 
0 
0 
0 
6 
4 
10 
32 
10 
42 
47 
17 
64 
2003 (Nov 02-Oct 03) 
5 
4 
9 
1 
1 
2 
6 
4 
10 
24 
3 
27 
36 
12 
48 
2004 (Nov 03-Oct 04) 
6 
3 
9 
0 
0 
0 
2 
4 
6 
18 
9 
27 
26 
16 
42 
2005 (Nov 04-Apr 05)* 
3 
n/a 
n/a 
0 
n/a 
n/a 
6 
n/a 
n/a 
12 
n/a 
n/a 
21 
n/a 
n/a 
Total 
69 
28 
97 
8 
4 
12 
47 
31 
78 
184 
68 
252 
308 
131 
439 
less during TP2. One notable exception was in October 
1998, when seven strandings occurred but minimal 
spiny dogfish landings were reported. Monthly Hl-no 
and Hi-other strandings showed no seasonal pattern 
across months and years (Fig. 3). Monthly HI-CBD 
strandings, however, showed a similar pattern to HI- 
FI strandings during TP1 and continued to show some 
periodicity afterwards, with increases primarily during 
winter months. 
With the UME threshold method, the stranding 
threshold for HI-FI strandings for the NC winter mixed 
MU was 2.95. This threshold was exceeded 7 out of 18 
months of the winter spiny dogfish fishing seasons dur- 
ing TP1, or 39% of the time (Fig. 4). During TP2, the 
threshold was exceeded as a result of bycatch in other 
fisheries in three months, or only 10% of the time: No- 
vember 2001 from strandings south of Cape Lookout; 
April 2003 from strandings north of Cape Hatteras, 
and November 2004 from strandings south of Cape 
Lookout. 
During summer, the stranding threshold produced by 
the UME threshold method for the northern NC MU 
was 1.77, and the strand- 
ing threshold for the south- 
ern NC MU was 2.19. The 
stranding threshold was 
exceeded three times for 
the northern NC MU, once 
during TP1 in May 1999 
(6% of the time; 1 out of 18 
months) and twice during 
TP2 in October 2001 and 
October 2004 (8% of the 
time; 2 out of 24 months) 
(Fig. 4). For the southern 
NC MU, the stranding 
threshold was exceeded only 
once, in October 1998 dur- 
ing TP1 (2% of the time; 1 
out of 42 months) (Fig. 4). 
With the use of the re- 
gression equation, the 68% 
Cl and 95% Cl values had 
wide bounds around the 
predicted bycatch estimates 
Table 2 
Mean (standard deviation [SD]) of monthly bottlenose dolphin (Tursiops truncatus) 
strandings by human interaction (HI) categories in the winter (November-April) during 
time period (TP) 1 (November 1997-October 2000) (n = 18) and TP2 (November 2000- 
April 2005) (n = 30). The HI categories are as follows: HI-FI (evidence of fishery interac- 
tion), and Hi-other (evidence of mutilation, propeller wounds), Hl-no (no signs of HI), 
and HI-CBD (human interaction could not be determined). For this study, data were not 
available (n/a) for the 2005 summer season (May-October) and thus totals for 2005 are 
for a partial year, denoted by an asterisk. 
HI category 
Time period 
Mean (SD) per month 
P-value 
HI-FI 
TP1 
2.39 (1.72) 
*0.001 
HI-FI 
TP2 
0.87 (1.04) 
Hi-other 
TP1 
0.33 (0.69) 
0.11 
Hi-other 
TP2 
0.07 (0.25) 
Hl-no 
TP1 
1.11 (1.02) 
0.54 
Hl-no 
TP2 
0.90 (0.80) 
HI-CBD 
TP1 
4.50 (3.31) 
0.16 
HI-CBD 
TP2 
3.43 (2.45) 
