As people enjoy fishing the Bay of Plenty's blue this summer, fresh information has surfaced that could help recreational anglers save hundreds of thousands of fish per year and help sustain their fishery.

A research project looking at survival rates of recreationally caught snapper that are released back to the sea shows around 85 per cent of the fish were still alive at the end of the first experiment.

Fisheries New Zealand principal scientist Bruce Hartill led the project in his former role at the National Institute of Water and Atmospheric Research, with experiments conducted last April and November.

The project, commissioned by Fisheries NZ and undertaken by NIWA in collaboration with Ngāti Kuta, Legasea and Bluewater Marine Research, has hooked some useful information.

Bruce says although the numbers can vary from year-to-year, recreational fishers land more than 4000 tonnes of snapper annually in NZ.

Bearing on sustainability

'For every snapper landed there will be about five times that number that are under the minimum legal size, which will be returned to the sea. What happens to those fish can have a real bearing on sustainability.”

The research took place in Mangahawea Bay, off Moturua Island in the Bay of Islands, with volunteers fishing from a charter boat at depths of 5m to 35m.

The details of each captured snapper were recorded, including how the fish was hooked and what depth it came from. The fish were then quickly transferred to one of nine holding nets and monitored for the following five days.

Preliminary results from the first experiment suggest snapper that are hooked in the throat are about five times more likely to die after being released than those which are lip hooked.

Mortality rates were also about five times higher when the snapper were caught in depths greater than 25m than if they were caught in less than 10m.

Help aid survival

Bruce says two main impacts on fish survival rates were the depth they were caught and how they were hooked. 'But there are some things we can do to help.

'Using recurve hooks, which are less likely to be swallowed by the fish; handling them carefully, making sure not to touch the eyes or the gills; and releasing them quickly will give them the best chance of survival.

Bruce says if a fish was caught in deeper water, using release weights will help get the fish back down to their capture depth before they are free to swim away.

'Anyone that goes fishing wants the same thing – both a feed for today, and healthy fish in the water for tomorrow, so handling practices and the gear used can make a real difference.”

Final survey results are expected by June. Bruce says results will give anglers a better understanding of the consequences of throwing fish back 'so there's less unseen mortality, and help fisheries managers set optimal fishing regulations, such as daily bag and minimum size limits”.

To learn fish handling practices, visit: https://fishcare.co.nz/handling-and-releasing