BeschrijvingMany damselfishes (Pomacentridae) are herbivorous or omnivorous with an important contribution of different kinds of plants in their diet. However, few inhabit seagrass meadows and none can be considered as seagrass-eating specialists. The footballer demoiselle, Chrysiptera annulata, is a small damselfish found in the seagrass meadows on the reef flat of the Great Reef of Toliara (Madagascar, Mozambique Channel). Chrysiptera annulata is territorial, defending a small coral reef boulder generally supporting macroalgae. Here, In this unusual habitat for pomacentrid, we first aimed to describe at best the diet of this damselfish to seek for their ability of feeding seagrass. We also questioned the trophic niche overlap between the footballer demoiselle and 3 other sympatric omnivorous/herbivorous damselfishes (Chrysiptera unimaculata, Pomacentrus trilineatus and Plectroglyphidodon lacrymatus) displaying different trophic strategies. Using gut content and stable isotope approaches, we showed that footballer demoiselle is not a seagrass consumer but is omnivorous. Using SIAR, a stable isotope mixing model, we conclude it consume turf algae in large quantities and different benthic or planktonic invertebrates in lower proportions. According to a SIBER approach using stable isotopes data, isotopic niche of the footballer demoiselle would partly overlap the isotopic niche of its congeneric C. unimaculata, but not those of P. trilineatus and P. lacrymatus. Trophic strategies of C. annulata differed from farming species such as P. lacrymatus or from less territorial herbivores such as P. trilineatus. Its habitat (seagrass meadow) on the Great Reef of Toliara could limit competition with C. unimaculata, a species displaying the same behavior and the same isotopic niche but living on the reef itself.
|Periode||29-jun-2015 → 19-jul-2015|
- fatty acid analysis
- stable isotope analysis
- tropical fish ecology