India, May 5 -- Researchers, including Dr Nick Shears from the University's Institute of Marine Science, say existing marine reserves in the Hauraki Gulf are not large enough to protect crayfish."We estimate that inside reserves, crayfish have declined by 59-80 per cent in the past 10-15 years despite being inside a strict 'no-take' area," he says."Further, our estimate in the Hauraki Gulf is that the crayfish stock is just 3-12 per cent of unfished levels. That's significantly lower than official fishery estimates of 20 per cent."The study combined long-term crayfish monitoring data from three marine reserves and their surrounding fished coasts from the past five decades. It includes data from Tawharanui collected by the late Dr Roger Gr...