Broadhurst and Kennelly: Composite square-mesh panel in codends for reducing bycatch in an Australian prawn-trawl fishery 
661 
HI Control, n = 937 
> 
o 
c 
0 
13 
cr 
0) 
c 
o 
o 
0 
Q_ 
25 n 
B 
20 - 
15- 
10 - 
5- 
0 
| Control, n = 261 
□ Composite-panel, n= 166 
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Figure 5 
Size-frequency distributions of discarded red spot whiting caught with control and com- 
posite-panel codends from (A) Southwest rocks, (B) Yamba, and (C) Ballina. 
blackeyes, flute fish, red bigeye, and, in particular, 
stout and red spot whiting, were all significantly re- 
duced by the composite-panel, which contributed to- 
wards a reduction in the mean weight of discarded 
bycatch at all locations from 23.5% to 41% (Fig. 3). 
Assuming minimal differences between the various 
vessels and their gear, the relative availability of 
these fusiform species throughout waters off New 
South Wales may explain the variations in the mean 
reductions of total discarded bycatch at each of the 
ports and across the fishery. For example, there were 
no red spot or stout whiting captured at Port 
Stephens (Fig. 3, E-G), and there was only a 23.5% 
reduction in total discarded bycatch by the compos- 
ite-panel at that location (Fig. 3B). In contrast, the 
discarded bycatch at Yamba and Ballina included 
large numbers of whiting and red bigeye (up to 500 
fish and 1,000 fish, respectively, from each tow in 
the control net) (Fig. 3, E-F and K) and correspond- 
ingly large percentage reductions in total discarded 
bycatch (41% and 39.5%, respectively) (Fig. 3B). 
The above reductions in total discarded bycatch 
with the composite-panel provide a possible expla- 
nation for the significant increase in catches of 
