Preliminary evaluation of the costs and benefits of prawn stocking to enhance recreational fisheries in recruitment limited estuaries

Abstract

Hatchery-based fisheries enhancement involves supplementing natural recruitment through releases of cultured individuals to increase the productivity of wild harvest fisheries. The responsible approach to marine stock enhancement recommends economic assessment of enhancement endeavours be undertaken, but such assessments are difficult for recreational fisheries and consequently examples of such analyses are rare. This paper describes a bioeconomic assessment of hatchery releases to enhance a recreational Eastern King Prawn fishery in a recruitment limited coastal lake. Sensitivity analysis on the model indicated that parameters estimating growth and economic impact were the most important drivers of the model. A full Monte-Carlo Analysis of Uncertainty indicated that a scenario releasing 3,000,000 Eastern King Prawn postlarvae is most likely to yield over 5000kg of harvest. Cost-Benefit results indicated that such a scenario would most likely generate AUD5.48 benefit for every AUD1.00 invested in releasing Eastern King Prawn. Achieving a benefit of less than AUD2.37 was extremely unlikely. This study indicates a favorable assessment of the potential economic benefits derived from a release of 3,000,000 Eastern King Prawns into Wallagoot Lake. Also, the simple approach presented provides a framework which may be useful for assessing other recreational fishery enhancement projects. Bioeconomic modelling is an important tool for understanding the potential benefits and risks of enhancement or sea ranching projects.