GENETIC IMPROVEMENT AND SELECTION IN SHELLFISH: A REVIEW BASED ON OYSTER RESEARCH AND PRODUCTION

SUMMARY- Despite the economic importance of shellfish, genetic improvement has not yet had a great impact on these species. Shellfish farming is traditionally based on wild species whose natural populations are often overexploited and do not fulfill market demand. Up to now, the most effective answer to disease problems or for the improvement of productivity has been the introduction of new species. However, the introduction of new species is constrained by their ecological impact and is also limited by the availability of suitable species. Genetic improvement of local species should therefore be of great importance as a viable alternative for the long term sustainability of the shellfish industry. The different approaches to genetic improvement include polyploidization, hybridization and selection. Polyploidization has the most potential for immediate application to commercial breeding as triploid induction has already been achieved for many shellfish species. Comparative performance of triploids versus diploids has been studied in detail in oysters: triploids show better growth performances due to a reduced reproductive outpu