Science Centres: Fisheries

Craig Aston, skipper of the Lady Helen Rose, putting down a cod pot off D’Urville Island. (Photo: Ron Blackwell, NIWA)

NIWA fisheries scientists successfully tagged and released 995 blue cod as part of a Ministry of Fisheries survey in the Marlborough Sounds and Tasman and Golden Bays. This is the fifth survey in the region to assess changes in what appears to be a declining blue cod population.

Blue cod were caught at 748 pot and line stations throughout the area over three weeks in September. Fish were tagged in the outer Pelorus Sound and around D’Urville Island to investigate fish movements and growth rates. A 2004 tagging study achieved very good return rates, at 13%. Most fish were caught within two kilometers of where they were released up to three years ago, indicating they don’t move much. This finding has important consequences for the sustainable management of the fishery.

Anyone who catches a tagged fish should record its length and location of capture and return the tag (or tag number if the fish is undersized) to NIWA Nelson.