Trawl fisheries bycatch
Accurate reporting on the amount of fish and invertebrates that are caught and discarded by New Zealand’s commercial fishing industry is vital to effective management of these fisheries.
Deepwater fisheries are those fisheries which predominantly occur in offshore waters beyond the 12 nautical mile limit of the territorial sea, out to the 200 nautical mile limit of New Zealand’s exclusive economic zone (EEZ). They produce about 80% of New Zealand’s total annual catch and are worth NZ$650 million in export earnings per annum.
New Zealand’s commercial fisheries are managed by the Quota Management System (QMS). An important part of this system is the estimation and reporting of the amount of fish and invertebrate species that are caught and discarded by commercial fishing vessels.
For deepwater fisheries, monitoring of catch at sea is carried out by government observers on board selected vessels. NIWA is responsible for analysing the data collected to estimate annual catch and discard levels in each fishery.
Because observers monitor about 25% of deepwater trawls, statistical modelling techniques are used to generate estimates of bycatch and discards for the unobserved portion of each of the key New Zealand deepwater target trawl fisheries.