Larval supply and juvenile recruitment of coral reef Wshes to marine reserves and non-reserves of the upper Florida Keys, USA

For marine organisms, decoupling between the planktonic larval stage and the benthic-associated juvenile stage can lead to variable patterns of population replenishment, which have the potential to inXuence the eVectiveness of marine reserves. We measured spatial and temporal variability in larval supply and recruitment of Wshes to coral reefs of diVerent protection levels and tested whether protection level inXuenced the relationship between supply and recruitment. We sampled pre-settlement larvae and newly settled recruits from four reefs (two reserves and two nonreserves) in the Florida Keys National Marine Sanctuary, USA. Replicate point measures of larval supply over 14 months and 17 monthly measurements of recruitment varied signiWcantly among months and sites. Sites with the same protection level had signiWcantly diVerent patterns of larval supply as well as larval and recruit diversity, but recruitment magnitude diVered only by protection level, where densities were greater at reserves. DiVerences in larval supply among sites included two particularly large peaks in larval abundance at one site, possibly associated with the observed passage of small-scale oceanographic features. To examine whether relationships between larval supply and recruitment varied by protection level, we selected one species that was present in both the light trap samples and the monthly recruitment surveys. Recruitment of the bicolor damselWsh Stegastes partitus was signiWcantly and positively related to larval supply at three of the four sites thus, protection level did not inXuence this linkage. Since local variability among sites can lead to spatial diVerences in population replenishment, characterization of larval supply and recruitment to potential marine reserve sites may help to identify optimal locations in a region and contribute to more eVective reserve design.