We investigated the effects of body size, feeding strategy and depth distribution on the trophic resource partitioning among the 26 dominant fish consumers in a fish assemblage on the central Mediterranean shelf-break. The fish assemblage was structured in two major trophic guilds: epibenthic and zooplanktonic feeders, according to the position of each predator along the benthos-plankton gradient. Within each main guild, the species were segregated along a prey-size or fish-size gradient into five further guilds. Fish size and prey size were strongly correlated, indicating that the prey-size niche can be well explained by predator size. Fish consumers showed a significant negative correlation between the similarity in prey type and the similarity in depth distribution; most species with similar trophic preferences segregated along the depth dimension. The only predators overlapping in both food and depth preferences were those with a more specialist trophic behavior. These results suggest that fish body size and depth preferences are the two main niche dimensions, explaining a large part of the coexistence between the Mediterranean shelf-break fish consumers.
Food resource partitioning in a Mediterranean demersal fish assemblage: the effect of body size and niche width
Colloca Francesco;
2010
Abstract
We investigated the effects of body size, feeding strategy and depth distribution on the trophic resource partitioning among the 26 dominant fish consumers in a fish assemblage on the central Mediterranean shelf-break. The fish assemblage was structured in two major trophic guilds: epibenthic and zooplanktonic feeders, according to the position of each predator along the benthos-plankton gradient. Within each main guild, the species were segregated along a prey-size or fish-size gradient into five further guilds. Fish size and prey size were strongly correlated, indicating that the prey-size niche can be well explained by predator size. Fish consumers showed a significant negative correlation between the similarity in prey type and the similarity in depth distribution; most species with similar trophic preferences segregated along the depth dimension. The only predators overlapping in both food and depth preferences were those with a more specialist trophic behavior. These results suggest that fish body size and depth preferences are the two main niche dimensions, explaining a large part of the coexistence between the Mediterranean shelf-break fish consumers.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.