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 particularly 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 significant 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.

Direct evidence of a biophysical retention mechanism for coral reef fish larvae

“…Larval patch dynamics-Presumably, coral reef fish larvae and planktonic organisms in general occur in patches (Haury et al 1978;Victor 1984), but direct evidence of the three-dimensional configuration of single-species, stage-specific coral reef fish larval patches has not been previously reported. Horizontal size estimates of S. partitus patches provided in this study (2-6 km) are in agreement with the findings of Williams and English (1992) of late-stage, multispecies larval patches of at least 6 km across, arriving onto the reef, but shy of estimates of patch size for presettlement wrasses of 20-46 km (Victor 1984).…”

“…These results imply that larvae initially dispersing as patches tend to remain coherent, even perhaps until settlement. In fact, high variance in age observed within a settling cohort may not necessarily indicate that natal cohorts are dispersed, as suggested by Danilovicz and Sale (1999), but that discrete cohort patches may merge together passively or actively within specific local oceanographic features (e.g., convergences, accumulation area, strong gradients in habitat), which influence cohort characteristics (Victor 1984;Searcy and Sponaugle 2000). Patch generation and maintenance may be due to behavior-mediated aggregation in addition to passive accumulation (Boehlert and Mundy 1993).…”

“…In the case of island circulation, processes limiting advection away from the island include trapped eddies and other island-mass ef-fects such as topographically steered currents (Boden 1952;Sanders 1981;Boehlert et al 1992). Because physical processes act throughout the larval life history of coral reef fishes, they have the potential to influence a range of behaviors, including the strategy and timing of adult spawning (Parrish et al 1981;Hugget et al 2003), the timing of settlement and metamorphosis to juvenile stages (Victor 1984;Sponaugle and Cowen 1994), as well as diel migrations and vertical preferences during larval ontogeny (Leis 1986). Vertical migrations can be used to move between vertically stratified water masses or currents.…”

Spatial patterns of endemism in shallow-water reef fish populations of the Northwestern Hawaiian Islands

“…Recently, the endemism of coral reef fish faunas (Wellington & Victor 1992, Victor & Wellington 2000, particularly those of isolated oceanic islands (Robertson 2001), has been a popular research topic for several complementary reasons. One reason of general biogeographic interest is that speciation and the origin and maintenance of biodiversity are undoubtedly related to degrees of isolation and endemism.…”

Biogeography and Population Connectivity of Coral Reef Fishes

“…It seems intuitive that the longer a larval propagule stays in the water column, the farther it will travel. However, there is no consistent correlation between pelagic larval duration (PLD) and geographic range size (Lester et al, 2007;Lester & Ruttenberg, 2005;Victor & Wellington, 2000), or between PLD and population genetic structure (Weersing & Toonen, 2009). Previously reported correlations appear to have been driven by species lacking a pelagic larval phase .…”