Age- and Sex-Specific Survival of Northern Grand Bank Capelin (Mallotus villosus)

Abstract

Age-specific, sex-specific survival rates for immature and mature capelin (Mallotus villosus) were estimated by linear least-squares models, using abundance data derived from annual acoustic/trawl research surveys conducted from 1982 to 1990 on the northern Grand Bank. Survival estimates for age 2 immature fish were comparable between sexes (annual survival equals approximately 40%). Survival estimates for age 4 mature fish differed between sexes, with females having a higher (25–51%) average survival estimate than males (6%). Survival estimates for immature and mature age 3 fish were equivocal; immature males and females had comparable rates (30.3–32.3 and 15.2–26.6%, respectively) whereas a greater proportion of mature females (25–50%) survived than of mature males (2.5–13%). The stated ranges denote survival estimates including and excluding an influential data point, respectively. Higher average survival of mature females than of mature males may be a result of sex-specific behavior during beach spawning. The average annual contribution of surviving mature females to the total number of female spawners was estimated as 24–47%.