Loss of genetic diversity due to fishing pressure

Loss of genetic diversity in the orange roughy, Hoplostethus atlanticus, caught off New Zealand, was measured by gel electrophoresis of nine polymorphic enzyme loci. There has been a significant reduction in genetic diversity on three spawning sites over the past 6 years, during which time the virgin biomass has been reduced by 70%. It is suggested that fishing activities which concentrate on spawning populations differentially remove the older and more heterozygous individuals from the virgin stock. Commercial fishing activities may have had significant genetic effects on fish stocks without reducing them to near-extinction levels.