Growth in pearl oysters: A review of genetic and environmental influences

Pearl oysters have high economic value. These species have gained much interest of research in growth, producing disease resistant and viable stocks for aquaculture facilities. Growth-related genes, such as insulin-related peptide receptor and the IGF system, and its components ERKs and MKK4 have been documented to influence growth in pearl oysters. Temperature, salinity, culture condition among other environmental factors were also reported to influence growth by influencing the physiological functions of pearl oysters such as clearance rate, oxygen consumption, respiration rate, excretion rate and expressed in parameters such as the scope of growth and the net growth efficiency. Genetic and artificial breeding techniques have been utilized in breeding programmes to improve growth and pearl quality in pearl oysters with mass selection and hybridization documented as efficient methods to improve growth traits. One problem observed during the growth of pearl oysters is the unsynchronized growth. Transcriptome and metabolomics studies have been undertaken to understand the underlying mechanism of this problem. The pearl oyster immune response to stress has also been reported to cause growth differences and needs to be thoroughly investigated to help produce viable stocks with synchronized growth for the aquaculture industry.