Authors: 

Broadhurst, M.K., Brand, C.P. and Kennelly, S.J.

Journal/Publisher Name: 

Fisheries Research

Contact information: 

Three codends 1. a control, 2. a simplified Nordmore-grid and 3. one with a radial escape section were tested aboard trawl vessels off New South Wales Australia, to determine the effects on the catch of bycatch and target species.  The codend with a radial escape section and the simplified Nordmore-grid retained fewer school prawns by weight 11.5% and 4.6% resepectively, compared to the control net.   The Nordmore-grid codend caught 50% fewer yellowfin bream than the radial escape section net and 55% fewer than the control net.  Both trial codends significantly reduced the predicted mean weight (36% Nordmore-grid and 74.3% radial escape section) and number (17.3% and 49.3%) of bycatch.  The Nordmore-grid codend retained significantly fewer bycatch by weight (59.8%) and number 38.7%) than the radial escape section codend.  In addition, the Nordmore-grid codend retained significantly fewer Ramsey’s perchlet than the control (48.3%) and radial escape section (50.7%) and fewer southern herring (69.4% and 57.6% respectively).  Significantly more silver biddy sized 9.5 to 10.5 cm total length were retained inthe control codend compared to the Nordmore-grid and radial escape section codends.

Field Studies:
Location Fishing gear Reduction technique Bycatch species Effect on bycatch species Catch Effect on target catch Type
New South Wales Australia Trawls Modified codend Bony Fishes The Nordmore-grid codend caught 50% fewer yellowfin bream than the radial escape section net and 55% fewer than the control net. Both trial codends significantly reduced the predicted mean weight (36% Nordmore-grid and 74.3% radial escape section) and number (17.3% and 49.3%) of bycatch. The Nordmore-grid codend retained significantly fewer bycatch by weight (59.8%) and number 38.7%) than the radial escape section codend. In addition, the Nordmore-grid codend retained significantly fewer Ramsey’s perchlet than the control (48.3%) and radial escape section (50.7%) and fewer southern herring (69.4% and 57.6% respectively). Significantly more silver biddy sized 9.5 to 10.5 cm total length were retained inthe control codend compared to the Nordmore-grid and radial escape section codends. Prawns The codend with a radial escape section and the simplified Nordmore-grid retained fewer school prawns by weight 11.5% and 4.6% resepectively, compared to the control net. In the wild