The decline of the Hauraki Gulf
Conservationists are calling on the government to take urgent action in the Hauraki gulf, which has lost more than half its marine life in the last century.
Snapper and crayfish numbers are down more than 80 percent since the 1920s, with 86 percent fewer trevally and sharks.
Mussels and other shellfish act as natural filters for ocean water, but some populations have been decimated by up to 90 percent, lowering overall water quality in the gulf and removing vital links in the food chain.