653 
Abstract .—The effectiveness of a 
new bycatch reduction device (BRD) 
was tested across a wide geographical 
range to determine its use in the NSW 
oceanic prawn-trawl fishery. Using four 
commercial trawlers, each from a dif- 
ferent port located in the fishery, we 
compared the catches and bycatches 
from conventional trawls with those 
from trawls containing composite pan- 
els of netting (60 mm and 40 mm) hung 
on the bar and inserted into the top 
anterior section of the codend (termed 
the composite-panel codend). This 
panel was designed so that the 40-mm 
mesh 1) would allow some small fish to 
escape and 2) would distribute the load 
anterior and lateral to the 60-mm mesh 
(which was located in an area where 
waterflow was thought to be greatest), 
allowing the 60-mm mesh to remain 
open and thus facilitate the removal of 
larger fish. Simultaneous comparisons 
against a control codend showed that 
the composite-panel codend signifi- 
cantly reduced the weights of discarded 
bycatch at all four locations (means re- 
duced by 23.5% to 41%) and the num- 
bers of juveniles of commercially impor- 
tant species, such as whiting, Sillago 
sp. (by up to 70%). At three of the loca- 
tions the composite-panel significantly 
increased the catches of the prawn 
Penaeus plebejus (5.5% to 14%) and, 
although not statistically significant, 
showed a similar trend at the fourth 
location (mean increase of 4%). As a 
result of this study, the composite-panel 
codend has been adopted and voluntar- 
ily used by fishermen throughout the 
New South Wales oceanic prawn-trawl 
fishery. 
Manuscript accepted 4 April 1997. 
Fishery Bulletin 95:653-664 ( 1997). 
The composite square-mesh panel: 
a modification to codends for reducing 
unwanted bycatch and increasing 
catches of prawns throughout the 
New South Wales oceanic 
prawn-trawl fishery 
Matt K. Broadhurst 
Steven J. Kennedy 
N.S.W Fisheries Research Institute 
RO. Box 21 Cronulla, New South Wales 2230, Australia 
E-mail address: broadhum@fisheries.nsw.gov.au 
In New South Wales (NSW), Aus- 
tralia, oceanic prawn-trawling in- 
volves over 300 vessels operating 
from 11 major ports along 1,000 km 
of coastline and is valued at ap- 
proximately A$17 million per an- 
num. Vessels operating in this fish- 
ery primarily target the eastern king 
prawn, Penaeus plebejus, although a 
significant portion of the total value 
in the fishery is derived from the 
sale of legally retained bycatch 
( termed “by-product” ) — comprising 
several species offish, crustaceans, 
and cephalopods. As in the major- 
ity of the world’s prawn-trawl fish- 
eries, however, significant numbers 
of nontarget organisms are also cap- 
tured and discarded in this fishery 
(for reviews see Saila, 1983; Andrew 
and Pepperell, 1992; Alverson et ah, 
1994; Kennedy, 1995). In NSW, this 
discarded bycatch includes indi- 
viduals of byproduct species that 
are smaller than the minimum com- 
mercial size and a large assemblage 
of noncommercial species (see 
Kennedy, 1995). 
Unwanted bycatch has been re- 
duced in several of the world’s prawn- 
trawl fisheries by means of modifica- 
tions to codends that contain bycatch 
reduction devices (BRD’s) (e.g. Wa- 
tson et al., 1986; Matsuoka and Kan, 
1991; Isaksen et ah, 1992; Rulifson 
et ah, 1992; Renaud et ah, 1993; 
Christian and Harrington 1 ). In gen- 
eral, these modifications have in- 
volved either 1) some form of rigid 
structure that functions by me- 
chanically separating larger un- 
wanted individuals or 2) a strategi- 
cally placed escape “window” made 
of netting that works by exploiting 
behavioral differences between 
prawns and smaller finfish. Al- 
though many of these modifications 
have proven effective in reducing 
bycatch from prawn trawls, some- 
times they have not been favored by 
commercial fishermen (see Kendall, 
1990; Renaud et ah, 1993) because 
of their size (in relation to the 
codend), their often complex design 
(e.g. Mounsey et ah, 1995), and, in 
some cases, their failure to main- 
tain prawn catches at the same lev- 
els as conventional trawls (e.g. 
Rulifson et ah, 1992; Robins- 
Troeger et ah, 1995; Christian and 
Harrington 1 ). 
One modification that has been 
successfully tested and adopted in 
1 Christian, P., and D. Harrington. 
1987. Loggerhead turtle, finfish and 
shrimp retention studies on four excluder 
devices (TEDs). In Proceedings of the 
nongame and endangered wildlife sympo- 
sium; 8-10 September 1987, Georgia, p. 
114-127. Dep. Nat. Resources, Social 
Circle, GA. 
