Establishing the Relationship of Major Histocompatibility Genotype and Egg Production in Bony Fish

While historically fishery scientists have employed spawner biomass as a proxy for recruitment, this relationship has been challenged due to its poor predictive power. To increase realism in the stock-recruit relationship biologists need to understand the factors that affect reproduction, and therefore recruitment. One factor that can affect reproduction is fish health, particularly parasite infection. Parasites rob the host of energy otherwise used for reproduction, which may lead to fewer, or smaller eggs produced, or lower egg quality. However, fish have genetic defenses against parasite infection including genes that help regulate the immune system termed the Major Histocompatibility (MH) genes. The goal of this study is to increase the understanding reproductive potential of fish by examining the relationship of MH genes, parasite burden, and egg production. To date, 42 female common snook, Centropomus undecimalis, have been examined. Variation in Gonadosomatic Index (mean ± SE: 3.50 ± 0.26; range: 1.35 – 8.77) and overall macro-parasite infection intensity (mean ± SE: 29.31 ± 6.73; range: 1.00 – 196.00) suggests that genotype may affect parasite burden and reproductive potential. MH gene class II A and B genes were examined to determine if specific alleles, or a variety of alleles were correlated with parasite burden and egg production. These data may help managers prepare for the challenges ahead by providing another tool to more accurately predict reproductive potential of fish stocks.