An inshore trawl survey, commissioned by Fisheries New Zealand and undertaken by the National Institute of Water and Atmospheric Research, has been completed.

The survey was the first since 1999, and the first in a series of three aimed at establishing the abundance and distribution of snapper, tarakihi, red gurnard and john dory off the west coast of the North Island, from 90 Mile Beach to Mana Island.

Manager of fisheries science Dr Shelton Harley said 76 species of fish were identified and almost 19,000 fish measured aboard the RV Kaharoa. Extra biological information was gathered from 5600 fish, including weight and maturity stage.

"We use the best available scientific information to manage our fisheries. This data will feed into the next stock assessment for these fisheries, and we will use it to make any changes to catch limits," Dr Harley said.

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"The information gathered for all species taken in the survey will improve our understanding of any changes in the marine environment since the last survey was done."

Voyage and project leader Dr Emma Jones (Niwa) said it had been a challenging survey to complete, covering of 34,636sq m along an exposed coastline with several periods of bad weather.

"We successfully completed 111 trawl and acoustic sampling stations, and 19 acoustic-only sampling stations, ensuring we met all the objectives of the project," she said.

Some rare and unidentified species that were caught had been kept for identification by Niwa and Te Papa scientists.

The research area included the West Coast Marine Mammal Sanctuary, for which a Maui dolphin mitigation plan was developed, and trawling ceased within areas closed to commercial trawling, gathering only acoustic data.

A Fisheries New Zealand observer was on-board to make marine mammal observations before and during each fishing 'event.' No Maui dolphins were sighted, but common dolphins, a pilot whale and one unidentified whale were seen.