Carbon isotopes in otolith amino acids identify residency of juvenile snapper (Family: Lutjanidae) in coastal nurseries
KAUST DepartmentRed Sea Research Center (RSRC)
Biological and Environmental Sciences and Engineering (BESE) Division
Marine Science Program
Reef Ecology Lab
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AbstractThis study explored the potential for otolith geochemistry in snapper (Family: Lutjanidae) to identify residency in juvenile nursery habitats with distinctive carbon isotope values. Conventional bulk otolith and muscle stable isotope analyses (SIA) and essential amino acid (AA) SIA were conducted on snapper collected from seagrass beds, mangroves, and coral reefs in the Red Sea, Caribbean Sea, and Pacific coast of Panama. While bulk stable isotope values in otoliths showed regional differences, they failed to distinguish nursery residence on local scales. Essential AA δ13C values in otoliths, on the other hand, varied as a function of habitat type and provided a better tracer of residence in different juvenile nursery habitats than conventional bulk otolith SIA alone. A strong linear relationship was found between paired otolith and muscle essential AA δ13C values regardless of species, geographic region, or habitat type, indicating that otolith AAs recorded the same dietary information as muscle AAs. Juvenile snapper in the Red Sea sheltered in mangroves but fed in seagrass beds, while snapper from the Caribbean Sea and Pacific coast of Panama showed greater reliance on mangrove-derived carbon. Furthermore, compound-specific SIA revealed that microbially recycled detrital carbon, not water-column-based new phytoplankton carbon, was the primary carbon source supporting snapper production on coastal reefs of the Red Sea. This study presented robust tracers of juvenile nursery residence that will be crucial for reconstructing ontogenetic migration patterns of fishes among coastal wetlands and coral reefs. This information is key to determining the importance of nursery habitats to coral reef fish populations and will provide valuable scientific support for the design of networked marine-protected areas. © 2011 Springer-Verlag.
SponsorsThe authors would like to thank H. Walsh, L. Houghton, M. Noble, N. DesRosiers, and G. Nanninga for field assistance, C. Braun for creating Fig. 1 and Dream Divers, Jeddah, Saudi Arabia for logistic assistance with boating and diving operations. Work in the Red Sea was supported by King Abdullah University of Science and Technology (KAUST) Award Nos. USA 00002 and KSA 00011 to S. Thorrold. Collections of snapper in the Caribbean Sea were funded by a Puerto Rico Sea Grant Program (Grant No. AN05-05-030) to I. Mateo, PADI Aware Foundation, Sigma Xi, and the Caribbean Coral Reef Institute. Additional funding was provided by the Woods Hole Oceanographic Institution and an International Society for Reef Studies-Ocean Conservancy Coral Reef Fellowship to K. McMahon. K. McMahon received support from the National Science Foundation Graduate Research Fellowship Program.