Endemism and the pelagic larval duration of reef fishes in the eastern Pacific Ocean

Abstract

We examined the relationship between pelagic larval duration (PLD) and species range for the wrasses and damselfishes of the eastern Pacific Ocean. This region and these species are par- ticularly appropriate for this analysis, since there is huge variation in the biogeographic range among these reef fishes, from endemics to islands a few kilometers in diameter to pan-Indo-Pacific ranges of 25 000 km or more. Furthermore, this variation in range occurs between pairs of congeners. We found no correlation between the mean (or maximum) PLDs measured from daily otolith increments and biogeographic range, for either family of reef fishes, and even after restricting the analysis to species with sample sizes over 50 individuals. A pairwise comparison of congeners showed, if anything, a sig- nificant inverse relationship between larval duration and range. The correlation between mean PLD and maximum PLD was very strong, even for large sample sizes (r = 0.987), indicating that mean PLD may be a good proxy measure for maximum PLD. We conclude that, at least within this region and within the limitations of this technique, larval duration appears not to determine species range.