The effect of birth date on fitness of female dwarf perch, Micrometrus minimus (Perciformes: Embiotocidae)

Abstract

Measured phenotypic selection on female birth date in this viviparous teleost fish by sampling birth-date cohorts over time in Tomales Bay, California. Four episodes of selection were measured: survival from birth to first reproduction, reproductive success in the first breeding season, survival to second reproduction, and reproductive success in the second season. Birth date had a significant impact on fitness in the first two episodes. Early born females were more successful in their first breeding season than late born females (directional selection on birth date), but early born females were less likely to survive the period between birth and first reproduction, relative to females born in the middle of the season (stabilizing selection on birth date). -from Author