Broadhurst and Kennelly: Composite square-mesh panel in codends for reducing bycatch in an Australian prawn-trawl fishery 659 
Table 3 
Summaries of one-tailed paired t-tests comparing the composite-panel and control codends. pt-v = paired i -value; n = number of 
replicates; all weights are in kilograms, disc = discarded; ret = retained; s. calamari = southern calamari; s. bug = smooth bug; rsw 
= red spot whiting ; sw = stout whiting; ebs = eastern bluespot flathead; and comm. sp. = commercial species. Significant P-values 
are in bold; insufficient data are marked by a dash. 
Port Stephens 
Southwest Rocks 
Yamba 
Ballina 
pt-v 
P 
n 
pt-v 
P 
n 
pt-v 
P 
n 
pt-v 
P 
n 
Wt of prawns 
2.139 
0.024 
16 
1.366 
0.090 
16 
2.104 
0.026 
16 
1.963 
0.034 
16 
Wt of disc bycatch 
4.467 
0.0002 
16 
2.930 
0.0001 
16 
5.518 
0.0001 
16 
8.254 
0.0001 
16 
No. of ret octopus 
— 
— 
— 
-0.913 
0.812 
16 
-1.959 
0.964 
15 
0.904 
0.190 
16 
Wt of ret octopus 
— 
— 
— 
-0.868 
0.800 
16 
-0.298 
0.615 
15 
-0.341 
0.631 
16 
No. of disc octopus 
— 
— 
— 
0.000 
® 
10 
— 
— 
— 
— 
— 
— 
Wt of disc octopus 
— 
— 
— 
-0.171 
0.566 
10 
— 
— 
— 
— 
— 
— 
No. of ret cuttlefish 
— 
— 
— 
-0.324 
0.624 
13 
— 
— 
— 
— 
— 
— 
Wt of ret cuttlefish 
— 
— 
— 
-0.434 
0.664 
13 
— 
— 
— 
— 
— 
— 
No. of disc cuttlefish 
0.631 
0.272 
10 
0.500 
0.312 
16 
— 
— 
— 
— 
— 
— 
Wt of disc cuttlefish 
0.165 
0.436 
10 
0.995 
0.167 
16 
— 
— 
— 
— 
— 
— 
No. of ret s. calamari 
— 
— 
— 
1.011 
0.166 
13 
— 
— 
— 
— 
— 
— 
Wt of ret s. calamari 
— 
— 
— 
1.532 
0.075 
13 
— 
— 
— 
— 
— 
— 
No. of disc s. calamari 
— 
— 
— 
0.703 
0.248 
12 
— 
— 
— 
— 
— 
— 
Wt of disc s. calamari 
— 
— 
— 
0.887 
0.197 
12 
— 
— 
— 
— 
— 
— 
No. of ret s. bug 
0.452 
0.329 
13 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of ret s. bug 
1.214 
0.124 
13 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of disc s. bug 
— 
— 
— 
-0.254 
0.597 
8 
-0.541 
0.701 
15 
— 
— 
— 
Wt of disc s. bug 
— 
— 
— 
0.344 
0.371 
8 
-0.593 
0.718 
15 
— 
— 
— 
No. of disc scollop 
— 
— 
-0.377 
0.644 
16 
-1.109 
0.542 
9 
— 
— 
— 
Wt of disc scollop 
— 
— 
— 
0.501 
0.312 
16 
0.348 
0.368 
9 
— 
— 
— 
No. of ret red mullet 
— 
— 
— 
— 
— 
— 
— 
— 
— 
-1.012 
0.833 
12 
Wt of ret red mullet 
— 
— 
— 
— 
— 
— 
— 
— 
— 
-0.345 
0.632 
12 
No. of ret rsw 
— 
— 
— 
0.893 
0.194 
14 
— 
— 
— 
— 
— 
— 
Wt of ret rsw 
— 
— 
— 
1.270 
0.113 
14 
— 
— 
— 
— 
— 
— 
No. of disc rsw 
— 
— 
— 
4.911 
0.0001 
16 
3.593 
0.004 
8 
3.704 
0.001 
15 
Wt of disc rsw 
— 
— 
— 
4.574 
0.0002 
16 
2.554 
0.019 
8 
3.979 
0.0007 
15 
No. of disc sw 
— 
— 
— 
— 
— 
— 
2.776 
0.011 
10 
2.958 
0.005 
16 
Wt of disc sw 
— 
— 
— 
— 
— 
— 
2.566 
0.015 
10 
3.077 
0.004 
16 
No. of disc john dory 
2.611 
0.012 
12 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of disc john dory 
3.174 
0.004 
12 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of disc ebs 
— 
— 
— 
— 
— 
— 
-1.139 
0.862 
14 
-1.037 
0.842 
16 
Wt of disc ebs 
— 
— 
— 
— 
— 
— 
-0.919 
0.812 
14 
-0.971 
0.826 
16 
No. of ret tiger flathead 
-0.349 
0.634 
13 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of ret tiger flathead 
-0.602 
0.721 
13 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of disc tiger flathead 
1.282 
0.111 
14 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of disc tiger flathead 
1.71 
0.055 
14 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of disc redfish 
0.947 
0.179 
15 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of disc redfish 
-0.131 
0.551 
15 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of leatherjacket 
— 
— 
— 
— 
— 
— 
— 
— 
— 
2.404 
0.014 
16 
Wt of leather jacket 
— 
— 
— 
— 
— 
— 
— 
— 
— 
2.15 
0.024 
16 
No. of red bigeye 
— 
— 
— 
— 
— 
— 
3.344 
0.002 
16 
2.528 
0.012 
15 
Wt of red bigeye 
— 
— 
— 
— 
— 
— 
4.122 
0.0004 
16 
2.548 
0.012 
15 
No. of flutefish 
— 
— 
— 
1.841 
0.045 
13 
— 
— 
— 
— 
— 
— 
Wt of flutefish 
— 
— 
— 
1.851 
0.044 
13 
— 
— 
— 
— 
— 
— 
No. of blackeyes 
4.364 
0.0003 
16 
— 
— 
— 
— 
— 
— 
— 
— 
— 
Wt of blackeyes 
5.459 
0.0001 
16 
— 
— 
— 
— 
— 
— 
— 
— 
— 
No. of gurnard 
— 
— 
— 
— 
— 
— 
— 
— 
— 
2.392 
0.018 
15 
Wt of gurnard 
— 
— 
— 
— 
— 
— 
— 
— 
— 
2.034 
0.033 
15 
No. of disc comm sp 
1.168 
0.1306 
16 
-2.282 
0.981 
16 
0.436 
0.334 
16 
-0.674 
0.744 
16 
cant differences detected in the size-compositions of stout 
whiting at Yamba (Fig. 6A); however, at Ballina, the 
control codend caught proportionally more small stout 
whiting than the composite-panel codend (Fig. 6B). 
Discussion 
This study has shown the effectiveness of square 
mesh panels in allowing nontarget organisms to es- 
