The valuable NSW abalone fishery is based largely on populations in the south of the state. Annual catches peaked at over 1200t during 1971-1972, and remained above 600 t during the early 1980s. Despite increasingly strict management both catches and catch rates declined until a total allowable catch (TAC) was introduced in 1989. By 1992, the commercial component of the TAC was dropped to 333 t. The fishery has been in decline and the quota has continued to drop, primarily in response to impacts from the disease Perkinsus.
Natural re-colonisation of depleted areas of reef by abalone is limited due to the very localised dispersal of abalone larvae from spawning adults. In addition, abalone recruitment is limited to areas of reef providing adequate settlement substrate, shelter and food. Some remedial techniques have been developed in co-operation with industry to aid re-colonisation of depleted areas of reef in NSW, but these techniques are very labour-intensive and only result in slow rates of re-colonisation over small areas. The release of seed, produced from wild abalone in a hatchery, provides a significantly more powerful technique to rapidly enhance depleted populations of abalone over a large areas of reef.
NSW DPI has made good progress in hatchery production and experimental release of seed abalone in a project supported by grant funds from the Fisheries Research and Development Corporation (FRDC Project 98/219). For the first time in Australia, successful year round conditioning and spawning of captive abalone brood-stock has been achieved at NSW DPI abalone research facility at Tomaree Head, Port Stephens. These achievements, in combination with intensified nursery production and early weaning of juveniles onto artificial diets, has enabled an estimated 10 fold increase in production per area of nursery over most conventional commercial systems used in the southern states. This improved technology will substantially reduce costs of producing juvenile abalone both for seeding of depleted reefs and for farming. More than 20 million larvae were seeded over 12 locations and more than 800,000 button size juveniles at 50 locations. Preliminary cost to benefit modelling incorporating production and deployment costs and size specific natural survivorship indicated that button size (7 to 12 mm) 6 to 8 month old juveniles as those likely to be the most cost effective for seeding depleted reefs.
Potential benefits of this continuing work are substantial. For instance, a doubling of the current annual commercial catch to levels of around 600 tonnes regularly achieved 10 to 15 years ago would add another $15 million pa to its value.
The major focus on continuing research and development is to: