All 15 snapper trawlers operating in New Zealand's most lucrative fishery now have video cameras installed to make sure they are not dumping fish.

The fishing vessels in snapper one fishery (SN1), off the east coast of the North Island, adopted the technology after a trial by Sanford Fisheries.

Electronic monitoring was announced in 2013 in a bid to prevent "dumping" - the practice of throwing out small but legal-sized snapper to target larger fish.

Monitoring systems also detect whether vessels are catching undersize fish, and send information to the Ministry for Primary Industries (MPI) about where and how fish are caught.


Primary Industries Minister Nathan Guy said increased monitoring led to greater transparency about commercial fisheries' activities.

"It will help to build social licence and the support of consumers, other fishers and the wider community," he said.

As part of the electronic monitoring initiative, the number of on-board observers on fishing vessels have been cut.

Sanford chief executive Volker Kuntzsch said 20 of his company's fleet now had cameras installed, and all trawlers had the technology fitted since the beginning of this year. Danish seining vessels still had MPI observers.