A new method to reconstruct fish diet and movement patterns from δ 13 C values in otolith amino acids
AuthorsMcMahon, Kelton W.
Fogel, Marilyn L.
Johnson, Beverly J.
Houghton, Leah A.
Thorrold, Simon R.
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AbstractFish ecologists have used geochemical values in otoliths to examine habitat use, migration, and population connectivity for decades. However, it remains difficult to determine an unambiguous dietary δ 13C signature from bulk analysis of otolith. Studies to date have focused on the aragonite component of otoliths with less attention paid to the organic fraction. We describe the application of compound-specific stable isotope analysis (SIA) to analyze amino acid (AA) δ 13C values from small amounts (<1 mg) of otolith powder. We examined δ 13C values of otolith and muscle AAs from a reef-associated snapper (Lutjanus ehrenbergii (Peters, 1869)) collected along a carbon isotope gradient (isoscape) from seagrass beds to coral reefs. Carbon isotope values in otolith and muscle samples were highly correlated within and among coastal habitats. Moreover, δ 13C values of otolith AAs provided a purely dietary record that avoided dilution from dissolved inorganic carbon. Otolith AAs served as a robust tracer of δ 13C values at the base of the food web, making compound-specific SIA a powerful tool for dietary reconstructions and tracking the movement of fishes across isoscapes.
CitationMcMahon KW, Fogel ML, Johnson BJ, Houghton LA, Thorrold SR, et al. (2011) A new method to reconstruct fish diet and movement patterns from δ 13 C values in otolith amino acids . Canadian Journal of Fisheries and Aquatic Sciences 68: 1330–1340. Available: http://dx.doi.org/10.1139/F2011-070.
SponsorsThe authors thank M. Berumen for field assistance and the crew of Dream Divers, Jeddah, Saudi Arabia, for boat and dive operation assistance. The site map was created by C. Braun. This research was based on work supported by awards USA 00002 and KSA 00011 made by King Abdullah University of Science and Technology (KAUST). Additional funding was provided by Woods Hole Oceanographic Institution and an International Society for Reef Studies - Ocean Conservancy Coral Reef Fellowship. K. McMahon received support from the National Science Foundation Graduate Research Fellowship Program.
PublisherCanadian Science Publishing