Plasticity in feeding selectivity and trophic structure of kelp forest associated fishes from northern Chile

Abstract

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 fi shes, we estimated the relative abundance of the potential sessile and mobile prey items and the diet of the fi sh species assemblage associated to kelp forest. Specifi cally, diet and feeding selectivity of the kelp-forest associated fi sh 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 fi shes 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 fi shes 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.

Habitat coupling writ large: pelagic‐derived materials fuel benthivorous macroalgal reef fishes in an upwelling zone

“…), targeting benthivorous fishes (Pérez‐Matus et al. ; Data ) inhabiting subtidal macroalgae‐dominated reefs, where they can play key functional roles (Ortiz ).…”

An experimental evaluation of macroalgal consumption and selectivity by nominally herbivorous fishes on subtropical rocky reefs

“…Bellwood et al (2006) highlighted the importance of omnivorous fishes on macroalgal consumption, especially for annual algae like Sargassum that are more likely to be consumed when senescent due to the higher epiphytes load. In general, omnivores are said to display limited selectivity towards different resources (Mantyka and Bellwood, 2007), since they would be able to ingest a large variety of food items (Raubenheimer et al, 2005;Pérez-Matus et al, 2012). This observation may be true to S. hispidus, that took a considerable amount of bites from the entire set of macroalgae offered and did not present any significant selectivity towards any algae.…”

“…Nevertheless, although the approach used in the present work does not necessarily assess the real diet of nominally herbivorous fishes, it sheds light into the influence these organisms may have on the distribution of macroalgal communities on rocky shores based on their potential consumption rate and selectivity/avoidance patterns. Numerous factors that can influence feeding selectivity by nominally herbivorous fishes have already been examined, such as algal nutritional quality (Pillans et al, 2004;Raubenheimer et al, 2005;Holzer et al, 2013;Goecker et al, 2005), food processing modes (Clements and Choat, 1997;Choat et al, 2004), presence of chemical and/or morphological defenses on algal thalli (Paul and Hay, 1986;Van Alstyne and Paul, 1990;Duffy and Paul, 1992;Hay et al, 1994), availability of the algal resource (Ferreira et al, 1998;Pérez-Matus et al, 2012), among others. Although not directly assessed in the present study, some of these factors can be used to infer the selectivity/avoidance patterns of nominally herbivorous fishes towards macroalgal species observed.…”

Contrasting definitive hosts as determinants of the genetic structure in a parasite with complex life cycle along the south‐eastern Pacific

“…and Rhynchocinetes typus (Pérez‐Matus et al . ). At around 30°S, Moreno & Flores () described as the primary prey crustaceans specifically Rhynchocinetes typus and Petrolisthes violaceus , whereas in the southern range (at approximately 38 °S), the primary prey is the crustaceans Neomysis sp., followed by unidentified crustaceans and Synalpheus spinifrons (González & Oyarzún ), and recently Cornejo‐Acevedo et al .…”

“…However, the existing works reveal that P. chilensis is a generalist species that preys on several species, such as crustacean, fishes, annelids, mollusks, echinoderms and others (Moreno & Flores ; González & Oyarzún ; Pérez‐Matus et al . ; Cornejo‐Acevedo et al . ).…”