Problems with prawn trawling nets: prawn behavioural research [Australia]
1990
Goeden, G.B. | Coles, R.G. | Mellors, J.E. (Queensland Dept. of Primary Industries, Cairns (Australia). Fisheries Branch)
To study methods of increasing the efficiency of prawn nets, a project was initiated in 1985, the objectives of which were to reduce the proportion of prawns that escaped the nets; reduce the incidence of damaged prawns in the net's cod end; and reduce the quantity of unwanted by-catch. To test the low efficiency of trawl-net ground-chains, a gear test team using SCUBA, and equipped with underwater video cameras, studied trawl net operations at sea. They were able to measure and photograph position and performance of ground chains and mud ropes on standard commercial prawn trawl nets on the fishing grounds. Results from these field trials supported laboratory experiments. The ground chains and mud ropes of the nets tested lagged behind the foot rope over most of the net's opening. This situation makes it virtually impossible for most prawns to be caught by the passing net. Future work will be oriented toward the improvement of the ground chain and foot rope configuration together with a reduction in net head-rope height.
显示更多 [+] 显示较少 [-]