Food partitioning and spatial subsidy in shelter-limited fish species inhabiting patchy reefs of Patagonia

GALVAN DE; BOTTO F; PARMA AM; BANDIERI L; MOHAMED N; IRIBARNE O

JOURNAL OF FISH BIOLOGY

Wiley-Blackwell

Lugar: Londres; Año: 2009 vol. 75 p. 2585 - 2605

0022-1112

Abstract: The most conspicuous reef-fish species from northern Patagonia are the carnivorous species Pseudopercis semifasciata, Acanthistius patachonicus, Pinguipes brasilianus and Sebastes oculatus. The four species occupy the fourth trophic level of the food web and constitute a trophic guild. Pinguipes brasilianus had the narrowest diet and most specialized feeding strategy, preying mostly on reef-dwelling organisms such as sea urchins, limpets, bivalves, crabs and polychaetes. The diet of A. patachonicus was characterized by the presence of reef and soft-bottom benthic organisms, mainly polychaetes, crabs and fishes. Pseudopercis semifasciata showed the broadest spectrum of prey items, preying upon reef, soft-bottom and transient organism (mainly fishes, cephalopods and crabs). All S. oculatus guts were empty, but stable isotopes analyses suggested that this species consumes small fishes and crabs. In general, P. brasilianus depends on local prey populations and eats different reefdwelling preys than the other species. However, P. semifasciata, A. patachonicus, and probably S. oculatus, have overlapping trophic niches and consume resources from adjacent environments. The latter probably reduces the importance of food as a limiting resource for these reef-fish populations, facilitating their coexistence in spite of their high trophic overlap.