Broadhurst et al.: Evaluations of Nordmore grid and secondary bycatch-reduction devices 
217 
■ Standard Ng n = 1 ,062 
□ Blubber-chute n = 977 
20 
15 
10 
5-| 
0 
n JiH 
■ EMF n = 1,117 
□ Blubber-chute n= 1,074 
20 
15- 
10 - 
5- 
0 
■ Fisheye n= 1,049 
□ Blubber-chute n = 996 
20-i D 
15 - 
ID 
5- 
0 
Standard Ng n = 1 ,068 
□ Fisheye n = 992 
20 - 
15- 
ID- 
S' 
0- 
kI 
d 
I Standard Ng n= 1,018 
□ EMF n= 1,088 
III 
MTi 
10 15 20 
Carapace length (mm) 
25 
30 
Figure 6 
Size-frequency distributions of school prawns ( Metapenaeus macleayi) 
caught with (A) the standard Nordmpre grid and blubber chute, ( B ) the 
extended mesh funnel and blubber chute, (C) the fisheye and blubber chute, 
(D) the standard Nordmpre grid and fisheye, and (E) the standard 
Nordmpre grid and extended mesh funnel. 
on the size-frequency compositions of school prawns 
failed to detect any difference between the standard 
Nordmpre grid and the blubber chute (Fig. 6A), such 
escapees were probably of all sizes. Another hypoth- 
esis to explain the loss of prawns from the blubber 
chute is that some prawns became entangled within 
the tentacles and large subumbrella of captured jelly 
fish and were directed, along with the jellyfish, out 
through the escape exit. In contrast, the long guid- 
ing panel and smooth contours of the Nordmpre grid 
may have allowed the prawns to detach from the jel- 
lyfish and thus enabled them to pass into the codend. 
Apart from a significant reduction in the numbers 
of bridle goby and noncommercial species caught by 
the EMF compared with the number caught by the 
standard Nordmpre grid in experiment 2, there were 
no other significant differences between the relative 
performance of the secondary BRD’s and the stan- 
dard Nordmpre grid (Fig. 5; Table 2). Given these 
results, therefore, it is likely that most of the fish 
