Abstract Genetic e¡ects on cold-stress tolerance were assessed for red drum (Sciaenops ocellatus), an economically important sciaenid ¢sh in the southern USA. Thirty¢ve families were generated via 'natural'spawning of multiple sets of ¢ve breeders (three dams  two sires) in individual brood tanks. O¡spring from the 35 families were transferred abruptly from an acclimation temperature of $24 1C to 5.7 1C and maintained subsequently at an average temperature of 6.5 1C. O¡spring were assigned a posteriori to individual brood¢sh (dam and sire) based on genotypes at nuclear-encoded microsatellites. Heritability of the survival^time probability function was estimated using a proportional hazard approach and an animaladditive model. The estimated heritability was 0.20 (95% CI: 0.07^0.40), indicating a signi¢cant genetic component to acute cold-stress tolerance in red drum
