Mar Biol (2009) 156:277–288 DOI 10.1007/s00227-008-1082-0 123 ORIGINAL PAPER Larval supply and juvenile recruitment of coral reef Wshes to marine reserves and non-reserves of the upper Florida Keys, USA Kirsten Grorud-Colvert · Su Sponaugle Received: 27 February 2008 / Accepted: 27 October 2008 / Published online: 15 November 2008  Springer-Verlag 2008 Abstract For marine organisms, decoupling between the planktonic larval stage and the benthic-associated juvenile stage can lead to variable patterns of population replenish- ment, which have the potential to inXuence the eVective- ness 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 pro- tection level inXuenced the relationship between supply and recruitment. We sampled pre-settlement larvae and newly settled recruits from four reefs (two reserves and two non- reserves) 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 lar- val 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 signiW- cantly and positively related to larval supply at three of the four sites thus, protection level did not inXuence this link- age. 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. Introduction One of the primary goals of marine reserve implementation is to maintain populations at ecologically sustainable levels, and widely documented beneWts of reserve implementation include accumulation of large adult Wshes and invertebrates (e.g. McClanahan et al. 1999; Halpern 2003; Russ and Alcala 2003). An inherent long-term component of this goal is ensuring that reserves receive suYcient numbers of larvae and recruits to contribute to the sustainability of future populations (Planes et al. 2000; Halpern and Warner 2003). Some reefs may support larger populations due to greater larval supply and juvenile recruitment, therefore these sites may be more eVective marine reserves (e.g. Warner et al. 2000). Population replenishment of marine organisms with bipartite life cycles is a function of the numbers of incom- ing larvae arriving at and settling to the benthos. Patterns of larval supply may vary based on biological parameters, such as egg production (Meekan et al. 1993), variability in early life history traits (Bergenius et al. 2002; Sponaugle et al. 2006), and larval mortality (Houde 1997), or with Communicated by S.D. Connell. K. Grorud-Colvert · S. Sponaugle Marine Biology and Fisheries Division, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA Present Address: K. Grorud-Colvert (&) Department of Zoology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA e-mail: grorudck@science.oregonstate.edu