FEWER CRAYFISH INSIDE RESERVES

DOC research from 2014 showed that fish and crayfish stocks at Goat Island Marine Reserve were lower than when the reserve was established more than 40 years ago.

By 2016 numbers had dropped a further 25 percent, according to ecoast’s Dr Haggit, an assertion backed by Dr Nick Shears, senior lecturer of marine sciences at Auckland University.

Research by Dr Shears and others has monitored crayfish inside the three main marine reserves – Goat Island Leigh, Tawharanui and Hahei – while keeping track of crayfish at sites outside reserve boundaries for comparison. Shears and Haggit have data going back 20 years for some sites.

The research shows crayfish numbers are falling outside as well as inside the reserves.

In 1995 there were 10 crayfish per unit area (500m2) in the spots monitored around the Leigh coastline and Kawau Island, compared to 40 inside Leigh Reserve.

The most recent data shows just five crayfish per unit outside the reserve and only 10 inside it – a 50 percent reduction outside and a 75 percent reduction inside the reserve.

“Current Leigh Reserve crayfish levels are less than that recorded outside the reserve in 1995,” Haggit says, and the other reserves in the survey show similar declines, indicating a much wider problem in CRA2, but this data isn’t currently being used by the Ministry of Primary Industry in assessments to set quotas.

Haggit would like to see extensions to all our marine reserves, plus the creation of more Marine Protected Areas. But ultimately, he says, crayfish management has to change: “The fisheries management areas are too big. They need to be smaller, with more local-based management.”