Responsible Genetic Approach to Stock Enhancements, Stock Restorations and Sea Ranching of Marine Fishes and Invertebrates

Stock restorations, stock enhancements and sea ranching of marine fishes and invertebrates have been implemented for several decades with various results. While considerable effort has been directed toward culture technologies to maximize production, scant attention has been given to genetic risks of stock supplementations to wild populations. Here, six steps are proposed to implement a genetically responsible approach: 1) assess effectiveness and ecological effects of supplementations; 2) establish goals and genetic benchmarks; 3) minimize genetic effects in brood-stock selection; 4) avoid intentional, or unintentional, selection that promotes domestication; 5) monitor released individuals with phenotypic, physical or genetic tags; and 6) minimize interactions between hatchery and wild individuals to protect genetic variability within and among populations. A literature review indicates that stock-enhancement and stock-restoration programmes around the globe seldom incorporate genetic principles into project designs. However, genetic risks can be substantial, because of inattention to brood-stock sizes, and because hybridization between hatchery-reared and wild individuals can lower the fitness of natural populations. Stock supplementations are often viewed as immediate solutions to a stock decline, but should be undertaken as a last resort because of the high cost of implementation and the substantial ecological and genetic risks they pose to wild populations.