Enhancing or restoring the productivity of natural populations of shellfish and other marine invertebrate resources

A broad review is provided of factors relevant to enhancing populations of invertebrate resources and methods promoting their recovery by natural recruitment, restocking or habitat restoration. The review focuses on the biological, technical, environmental, economic and biological factors affecting the feasibility of restoring or enhancing productivity of commercially valuable local invertebrate populations. Three categories of enhancement activity are recognized: restoring or enhancing stocks by conventional management methods, transplanting or seeding, and the use of juveniles produced from collectors in the wild or from hatcheries. Some guidelines are provided on issues related to enhancing recruitment, site selection, experimental closures, ecosystem considerations including predator control, as part of a stock management and enhancement programme. Ownership and co-management issues, and the necessary decisional rules for successful management are discussed, as well as how to reconcile the enhancement programme with other uses of the coastline. Spatial and geographical considerations are addressed, including allocation of areas for enhancement, rotational harvest schemes, use of refugia for protecting juveniles and the spawning stock, and the impact of the use of coastal zones for other human activities.