Log-transformed variance from individual growth curves as a potential indicator of resilience in Nile tilapia Oreochromis niloticus

Abstract The ability of the animal to cope with environmental changes may be measured by log-transformed variance of deviations from expected weights (LnVar). We calculate LnVar by fitting the expected individual growth curve based on longitudinal weights (LnVar ind ) of Nile tilapia that were grown in either an aerated or a non-aerated freshwater pond. We estimated genetic parameters for LnVar ind in Nile tilapia, the genetic correlation between LnVar ind and growth and the genetic correlation for LnVar ind between aerated and non-aerated pond. The heritability estimate for LnVar ind (0.28) in the non-aerated pond was higher than in aerated pond (0.06). In the aerated pond, genetic correlations of LnVar ind were − 0.44 ± 0.23 with daily growth coefficient (DGC) and − 0.45 ± 0.24 with harvest weight (W 5 ). In the non-aerated pond, genetic correlations with DGC and W 5 were − 0.68 ± 0.12 and − 0.52 ± 0.17, respectively. These values suggest that selection for fish with high growth rate will reduce LnVar ind . However, genetic correlation of LnVar ind between aerated and non-aerated pond was 0.50, suggesting that genetic improvement in the aerated environment will reduce LnVar ind in the non-aerated environment. Therefore, incorporating records from relatives in non-aerated pond is beneficial for breeding programs targeting this environment.