Effect of pelagic larval growth and size-at-hatching on post-settlement survivorship in two temperate labrid fish of the genus Symphodus

Abstract

The characteristics of fish larvae affect settlement and recruitment survival. We examined the effects of the variation in the early life characteristics (pelagic larval growth, pelagic larval duration, size-at-hatching and size-at-settlement) on post-settlement survival in 2 littoral species of the genus Symphodus (S. roissali and S. ocellatus) in the NW Mediterranean over 2 yr. We used otoliths to back-calculate growth rates and other early life traits exhibited by individuals at settlement and 2 mo after settlement. Size-at-hatching clearly affected the post-settlement survival of the 2 species. Juvenile survivors of S. roissali and S. ocellatus were mostly larger at hatching than settlers, and recently settled individuals were susceptible to size-selective mortality. Our study, however, showed that other larval traits (pelagic larval duration, larval otolith growth, size-at-age, size-at-settlement) were not always consistent with the growth-mortality hypothesis.