Stable isotope analyses were employed toexplore feeding and foraging habitats and trophic levelsof littoral fishes in a western Mediterranean MarineProtected Area (Egadi Islands, Sicily, Italy). Carbon andnitrogen stable isotope ratios were measured in primaryproducers, invertebrates and fishes collected in December2001 and January 2002. Fishes of the littoral regionof the Egadi Islands had isotopic signatures that fell intoa wider range for δ13C (about 6‰) than for δ15N (about3‰). Carbon isotope ratios were consistent with a foodweb based on mixed sources and two trophic pathwaysleading to different fish species. Differences in theisotopic composition between islands were higher forbenthivorous than for planktivorous fishes. The overallpicture gained from this study is of a isotopicdistinction between planktivorous and benthivorousfishes, resource partitioning facilitating the coexistenceof similar species within the same ecosystem, andspatial variability in the isotopic signatures and trophiclevel of fishes. Asymmetrical analysis of varianceshowed that estimated trophic levels were lower inthe area with the highest level of protection (Zone A)for only two out of the nine fishes analysed. As aconsequence, overall spatial differences do not seem to be a consequence of protection, since in most casestrophic levels did not change significantly betweenzone A and zones C where professional fishing(trawling apart) is permitted, but of natural sources ofvariation (e.g. variability in food availability and sitespecificfood preferences of fishes). However, theresults of this study suggest a different response atthe species compared to the community level.
|Numero di pagine||13|
|Rivista||Environmental Biology of Fishes|
|Stato di pubblicazione||Published - 2009|
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