Enhancing paua fisheries
Science Centres: Fisheries
Paua stocks around Stewart Island have declined over the last 10 years, and this has led to reductions in the allowable commercial catch for the area. Innovative, industry-led initiatives are aiming to provide solutions to help rebuild these stocks.
The New Zealand Paua Management Company (NZPMC) and NIWA have recently implemented a programme aimed at increasing the productivity of the Stewart Island paua fishery. The work, jointly funded by the Foundation for Science, Research and Technology and the NZPMC, will evaluate three management strategies. The work is being done within 12 small reporting zones (5–10 km long) on the east coast of the island. Four zones have been closed to commercial fishing, four will be harvested with an increased minimum legal size of 135 mm, and four will be reseeded with paua produced at a hatchery on the island. The last four zones will be fished as usual and monitored.
In February this year, in a combined effort by the NZPMC, local paua divers, and Southern Seafoods, more than 16 500 juvenile paua were released at three sites on the east coast of the island. The NZPMC also plans to reseed some sites with paua larvae. During September, a NIWA team surveyed two sites in each of the 12 zones to estimate the abundance of emergent paua (paua smaller than about 70 mm are usually cryptic and hide under boulders) and juvenile paua. It is difficult to assess the early success of reseeding because juvenile paua are very well hidden, but more juvenile paua were found in the reseeded areas than in other areas. The reseeded paua found during the surveys appear to be thriving, and new growth is clearly evident from casual examination of the shell. The light turquoise colour in the shell is caused by their hatchery diet, and the darker green/brown coloration reflects their growth since being transplanted into the wild.
Monitoring will continue for 3 years, after which the viability of the strategies will be assessed and NIWA will develop stock assessment methods appropriate for small-scale management. The small-scale management approach should ultimately lead to stocks being managed in a way that better reflects the biological processes within the population.