Equilibrium yield for the Hauraki Gulf snapper fishery estimated from catch and effort figures, 1960–74

To examine the significance of trends in catch, and to calculate an equilibrium yield for the Hauraki Gulf snapper fishery, catch and effort statistics for Danish seine, trawl, line, and non‐powered net fishing methods are analysed for the years 1960–74. The catch per day at sea of a trawl is used as standard, and a catch‐effort model is formulated. The model shows that a maximum equilibrium yield of 4153 t per annum from 7402 standard days (= trawl days) fishing at a catch‐rate of 561 kg per standard day can be expected from the fishery. The relative fishing power of each method is evaluated against the trawl. The analysis suggests that the increased landings of snapper from the Gulf during the last 6 years have over‐exploited the fishery. It is predicted that the down‐turn in landings which commenced in 1972–73 will continue unless management action is taken to reduce the level of effort or control landings.