MEPS 495:143-160 (2014)  -  DOI: https://doi.org/10.3354/meps10581

ABSTRACT: Regional and temporal variations in the diets of rocky shore suspension-feeders (the volcano barnacle Tetraclita serrata, the brown mussel Perna perna and the reef-building polychaete Gunnarea gaimardi) were assessed using fatty acid profiling. Specimens were collected up-current and down-current of a river mouth in 2 coastal regions ~50 km apart along southeastern South Africa during March and July of 2009. One of the rivers represents a marine-dominated system, and the other a freshwater-dominated system. Our aims were to assess any dietary differences among the 3 suspension-feeders, spatial changes in diet within each species (at regional  and local scales—50 and 15 km, respectively), and temporal changes in diet within each species. Fatty acid profiles clearly distinguished the species, with barnacles characterised by dinoflagellate and zooplankton-associated fatty acids; polychaetes, by diatom-associated fatty acids; and mussels, by a combination of mixed phytoplankton and mollusc-specific fatty acids (non-methylene interrupted). These interspecific differences probably arose in part from the contrasting feeding mechanisms employed. The distinctions in diet contribute to ecological partitioning of the suspended food within a highly competitive habitat. Regional- and local-scale intraspecific differences in diets were minimal to absent, but temporal distinctions in intraspecific diets were dominant features in the data set, confirming that the trophic environment for suspension-feeders can change markedly throughout a year.

KEY WORDS: Perna perna · Tetraclita serrata · Gunnarea gaimardi · River discharge · Suspended particulate matter · Niche partitioning · South Africa

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Cite this article as: Richoux NB, Vermeulen I, Froneman PW (2014) Fatty acid profiles reveal temporal and spatial differentiation in diets within and among syntopic rocky shore suspension-feeders. Mar Ecol Prog Ser 495:143-160. https://doi.org/10.3354/meps10581 Export citation Share:    Facebook - - linkedIn