Feeding activity of the cayenne pompano Trachinotus cayennensis (Cuvier 1832) (Perciformes, Carangidae) in estuaries on the western coast of the state of Maranhão, Brazil.

L M R Smith,J R Pinheiro-Júnior,J W J Azevedo,M H L Silva,L S Soares,A C L Castro,H R S Ferreira

doi:10.1590/1519-6984.182683

Abstract

The present paper addresses the feeding activity of Trachinotus cayennensis, collected in Lençóis Bay (1°18'S - 1°19'S; 44°51'W - 44°53'W) on the western coast of the state of Maranhão, Brazil. Sampling was conducted between June 2012 and June 2013 using driftnets with stretch mesh sizes from 95 to 100 mm. A total of 205 individuals (114 females and 91 males) were analyzed. Statistically significant differences in the sex ratio were found in June, September and December 2012. Food items were analyzed based on frequency of occurrence and volumetric method, with the subsequent calculation of the alimentary importance index. Three size groups were defined to determine possible ontogenetic changes in eating habits based on the size range of the individuals collected: I (˂ 29 cm), II (29.1 to 37.0) and III (≥ 37.1). Eleven food item categories were identified: mollusks, polychaetes, crustaceans, nematodes, insects, algae, bryozoans, ophiuroids, fishes, vegetal matter and sediments. The variety of items in the diet of T. cayennensis indicates considerable feeding plasticity and opportunistic behavior. Seasonal variations influenced the feeding pattern of the species, with greater feeding activity in the dry season. The considerable availability of resources in estuarine habitats of the western coast of Maranhão constitutes another factor that influences the feeding behavior of this species.

Highlights

Studies of the feeding ecology of a species provides basic biological knowledge and may allow inferences regarding its population dynamics, contributing to the understanding of such subjects as resource partitioning, habitat preferences, prey selection, predation, evolution, competition and energy transfer within and between ecosystems (Wootton, 1992; Lima and Behr, 2010)
Studies based on the analysis of stomach contents are among of the few resources that can provide information on feeding ecology and the trophic spectrum of fishes in their natural habitat (Palmeira and Monteiro-Neto, 2010)
Information related to its trophic ecology is available only to the coastal regions of the southeastern Brazil

Summary

Introduction

Studies of the feeding ecology of a species provides basic biological knowledge and may allow inferences regarding its population dynamics, contributing to the understanding of such subjects as resource partitioning, habitat preferences, prey selection, predation, evolution, competition and energy transfer within and between ecosystems (Wootton, 1992; Lima and Behr, 2010). Studies based on the analysis of stomach contents are among of the few resources that can provide information on feeding ecology and the trophic spectrum of fishes in their natural habitat (Palmeira and Monteiro-Neto, 2010). There are fishes that consume specific types of food, most species exhibit great plasticity in their diets (Lowe Mcconnell, 1999), making it difficult to verify patterns well defined. This food plasticity is an interaction between the quality/quantity of the food available in the environment and the degree of morphological and behavioral restrictions exhibited by the species and that are associated with ontogenetic variations (Luz et al, 2001).

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