A Permit Application to Biscayne National Park For a Study on Larval Production by Scleractinian Broadcast Spawners along the Florida Keys Reef Tract

Cooper, Wade

Recent evidence suggests larval production -- the aggregate of gamete production and fertilization success -- is a major deternimant of recruitment dynamics at large spatial scales, but few studies have directly addressed both gamete production and fertilization success concurrently in an attempt to determine spatiotemporal patterns in larval production. Patch reefs within the Florida Keys Reef Tract (FKRT) have relatively higher coral cover and adult colony size compared to offshore bank/barrier reefs, and thus may provide a substantial propagule source to degraded offshore reefs. However, the effect of decreased water quality in nearshore environments (Jones and Boyer 2002) on the reproductive output of patch reef populations compared to offshore populations is unknown. The objectives of this study are to identify scleractinian larvae sources and determine if larval production is a potential limiting factor for recruitment dynamics of two broadcast spawning corals, Montastraea faveolata and Siderastrea siderea, within the Florida Keys. These objectives will be accomplished by (1) determining if spatial patterns in fecundity (i.e., number of gamete produced) exist along the length of the FKRT, using histological and dissecting techniques; (2) determining the success of fertilization at select sites, using field estimates and modeling techniques; and (3) comparing larval mortality, settlement preferences, and post-settlement survival between the two focal species, using lab-reared larvae. Results from this study will provide useful information to managers of Florida Keys Reef Tract, particularly concerning the location of larval source reefs, population density thresholds below which fertilization success is unlikely (i.e., Allee effects), and temporal variability in larval production for some of the major framework building species. Abstract provided by author.