By-catch in Australian fisheries in Divisions 58.5.2, 58.4.2 and 58.4.3 during the 2002/03 and 2003/04 fishing seasons

This paper presents bycatch information for the Australian fisheries in Divisions 58.5.2, 58.4.2 and 58.4.3, with estimates of total removals by fishing ground for the 2002/2003 and 2003/2004 seasons. Bycatch in the trawl fisheries was low, approximately 1 to 2% of the total catch (target plus bycatch). Bycatch in the longline fisheries was higher, ranging from 8% to 14% of the total catch. Much higher percentage bycatch rates occurred in longlining grounds where the fishing effort and therefore target catch was low. The main bycatch species were skates and grenadiers in the D. eleginoides fishery and skates and C. rhinoceratus in the C. gunnari fishery. The total skate catch in Division 58.5.2 (including those cut from longlines) was 43 tonnes in 2002/2003 and 55 tonnes in 2003/2004. Results from the skate tagging program in Division 58.5.2 indicate that skates move very little between release and recapture, even after extended periods at liberty. The distances travelled ranged between 0.2 to 7 nm with periods at liberty ranging from 208 to 822 days. Growth rates estimated from recaptured skates were 20mm per/year in total length, 21mm per year in disk width and 0.14 kg per year in weight. Recapture rates were 2.5% for B. eatonii and 0.8% for B. murrayi for skates tagged in the trawl fishery and 0.05% for skates tagged in the longline fishery.