370 
Fishery Bulletin 108(4) 
Table 2 
Number of females and males, percent contribution of females, and the total number and percent contributions of each elasmo- 
branch species that were recorded during regular onboard observations of catches from gillnet vessels on the southwest coast of 
Australia. Plain font = targeted species; Plain font* = byproduct species i.e., those species not targeted but usually retained; Bold 
font = bycatch species, i.e., those species that are usually discarded. 
Common name 
Species name 
Female 
n 
Male 
n 
Female 
% 
Total 
n 
Total 
% 
Dusky shark 
Carcharhinus obscurus 
229 
208 
52.4 
437 
34.7 
Port Jackson shark 
Heterodontus portusjacksoni 
131 
120 
52.2 
251 
19.9 
Gummy shark 
Mustelus antarcticus 
151 
28 
84.4 
179 
14.2 
Sandbar shark* 
Carcharhinus plumbeus* 
86 
59 
59.3 
145 
11.5 
Whiskery shark 
Furgaleus macki 
69 
13 
82.9 
82 
6.5 
Southern eagle ray 
Myliobatis australis 
18 
14 
56.3 
32 
2.5 
Spinner shark* 
Carcharhinus brevipinna* 
17 
8 
68.0 
25 
2.0 
Western wobbegong* 
Orectolobus hutchinsi* 
7 
11 
38.9 
18 
1.4 
Gulf wobbegong* 
Orectolobus halei* 
3 
12 
20.0 
15 
1.2 
Smooth hammerhead* 
Sphyrna zygaena* 
8 
4 
66.7 
12 
1.0 
Cobbler wobbegong 
Sutorectus tentaculatus 
7 
4 
63.6 
11 
0.9 
Bronze whaler* 
Carcharhinus brachyurus * 
10 
1 
90.9 
11 
0.9 
Spotted wobbegong* 
Orectolobus maculatus* 
2 
7 
22.2 
9 
0.7 
Western shovelnose ray 
Aptychotrema vincentiana 
2 
4 
33.3 
6 
0.5 
Australian angelshark 
Squatina australis 
2 
4 
33.3 
6 
0.5 
Common sawshark 
Pristiophorus cirratus 
4 
1 
80.0 
5 
0.4 
Southern fiddler ray 
Trygonorrhina dumerilii 
3 
2 
60.0 
5 
0.4 
Grey nurse shark 
Carcharias taurus 
2 
0 
100.0 
2 
0.2 
Lobed stingaree 
Urolophus lobatus 
1 
1 
50.0 
2 
0.2 
Floral banded wobbegong 
Orectolobus floridus 
2 
0 
100.0 
2 
0.2 
Smooth stingray 
Dasyatis brevicaudata 
1 
0 
100.0 
1 
< 0.1 
Pencil shark* 
Hypogaleus hyugaensis* 
0 
1 
0.0 
1 
<0.1 
Ornate angelshark 
Squatina tergocellata 
1 
0 
100.0 
1 
<0.1 
Scalloped hammerhead* 
Sphyrna lewini* 
0 
1 
0.0 
1 
<0.1 
Western shovelnose stingaree Trygonoptera mucosa 
0 
1 
0.0 
1 
<0.1 
Total 
756 
504 
1260 
and more consistent numbers of A. vincentiana were 
particularly important for discriminating between the 
compositions of the samples caught by trawling and 
those obtained by both gillnetting and longlining, and 
greater and more consistent numbers of C. obscurus 
were especially important for discriminating between 
the samples taken by gillnetting from those obtained 
by both trawling and longlining (Table 4). The longline 
samples were discriminated from those obtained by 
both trawling and gillnetting by consistently greater 
numbers of D. brevicaudata. 
Length-frequency compositions of the four selected 
bycatch species by fishing method 
Wide size ranges of H. portusjacksoni, A. vincentiana , 
and S. australis and, to a certain extent, M. australis, 
were caught by trawling. However, the lengths of most 
H. portusjacksoni and M. australis were small and thus 
lay toward the lower end of their length ranges (Fig. 3). 
Although gillnetting also caught a broad size range 
of both H. portusjacksoni and A. vincentiana, it yielded 
predominantly larger S. australis and medium-size M. 
australis (Fig. 3). Although longline catches contained 
a wide size range of H. portusjacksoni and M. australis, 
they did not include the smallest individuals of these 
two species and only one of the A. vincentiana caught 
by this method was small (Fig. 3). No S. australis was 
caught by longlining. 
The H. portusjacksoni obtained by all three fishing 
methods ranged from 180 to 1300 mm TL (Table 
5), the latter length rarely being exceeded by this 
species throughout its range (Last and Stevens, 2009). 
The smallest individuals possessed conspicuous um- 
bilical scars and were therefore neonates. The length- 
frequency distribution of female H. portusjacksoni is 
trimodal, whereas that of males is bimodal, and these 
modes correspond to the first two modes of females 
(Fig. 4). These differences account for the lengths of 
many females greatly exceeding the maximum length 
of 815 mm for males (Table 5). The weights of H. por- 
tusjacksoni ranged from 39 to 12,250 g (Table 5). The 
