Revista Chilena de Historia Natural 85 (1): 29-48, 2012
RESEARCH ARTICLE
Plasticity in feeding selectivity and trophic structure of kelp forest associated fishes
from northern Chile
ALEJANDRO PÉREZ-MATUS, SHIRLEY PLEDGER, FRANCISCO J. DÍAZ, LARA A. FERRY & JULIO
One of the primary ways in which species interact with their environment is
through foraging; thereby directly consuming some fraction of their surrounding habitat. The habitat itself, in turn, may
dictate the types of foraging opportunities that are available to the inhabitants. To investigate the relationship between
habitat availability and diet composition of habitat-associated fishes, we estimated the relative abundance of the potential
sessile and mobile prey items and the diet of the fish species assemblage associated to kelp forest. Specifically, diet and
feeding selectivity of the kelp-forest associated fish assemblage were determined by calculating Manly’s alpha selectivity
index. We determined the diet of kelp forest associated fi shes and their foraging behavior by comparing prey availability
with those items present in the stomachs of fi shes captured by gill net and spear gun. We calculated the degree of dietary
overlap among fishes from four locations along the northern coast of Chile. Results indicate that utilization of prey by
predators is predominantly affected by potential prey availability. With the exception of the two carnivorous species such as
Pinguipes chilensis (Valenciennes, 1883) and Paralabrax humeralis (Cuvier & Valenciennes,
1828), whose diet did not change among sites, all other kelp-associated fi shes changed their dietary habitats to consistent
with the availability of local resources. Benthic resources changed among the different study sites, which led to differing
diets even in the same species from different locations. Eleven of the 12 kelp forest fi shes also showed some selectively for
benthic prey. We conclude that the ability of fishes to be plastic in their feeding preference and, therefore, partition the
benthic resources may set adaptations to co-exist in a dynamic environment such as kelp forest.
Chile, Manly α,
predation, trophic guilds, understory
