Management of restocking and stock enhancement programs: the need for different approaches

Abstract

Availability of technology for producing and releasing juveniles in the wild is not all that is required to proceed with programs for restocking (restoring stocks to the point where they can sustain regular harvests) and stock enhancement (increasing yields by overcoming recruitment limitation). Careful decisions need to be made about whether these interventions are likely to improve management of the fishery. Restocking should be used to rebuild stocks only where unduly long time frames are predicted for replenishment using other means, and when there are good reasons to indicate that release of juveniles will fast-track the process. Stock enhancement will be of benefit only where the supply of juveniles regularly falls well short of the carrying capacity of the ecosystem and desired levels of recruitment. In cases where restocking and stock enhancement are used as management tools, a second series of decisions are needed to manage the released animals. Otherwise, the benefits of the technology can be reduced or lost altogether. For restocking, the imperative is to ensure that the remnant wild stock, the released individuals, and their progeny are protected until replenishment occurs. This will often involve a moratorium on fishing. Successful stock enhancement will depend on releasing juveniles in a way that uses the carrying capacity of the ecosystem to deliver consistent, substantial harvests. Other important aspects of management for stock enhancement may include: (1) addition of habitat to increase overall carrying capacity, (2) vigilant monitoring for compliance with fishing regulations to promote natural replenishment, (3) restrictions on the entry of additional effort to encourage existing participants to invest in the process, and (4) independent assessments to ensure that optimum sustainable benefits are being obtained and to evaluate possible adverse impacts on the ecosystem.