Effect of environmental factors on the abundance of decapod crustaceans from soft bottoms off southeastern Brazil

Michele Furlan,Rogerio C Da Costa,Antonio L Castilho,Giovana Bertini,Lissandra C Fernandes-Goes,Vivian Fransozo

doi:10.1590/0001-3765201394812

Abstract

This study investigated the importance of variations in environmental factors affecting the abundance patterns of decapods on the southeastern Brazilian coast. Sampling was carried out monthly from January 1998 through December 1999 in Ubatumirim and Mar Virado, Ubatuba region, using a commercial shrimp fishing boat equipped with double-rig nets. Six areas adjacent to rocky shores were chosen. Bottom-water samples were collected using a Nansen bottle, to measure the temperature and salinity. Sediment samples were also obtained by means of a Van Veen grab, for determination of texture and organic-matter content. The association of environmental factors with species abundance was evaluated by Canonical Correspondence Analysis (α = 0.05). Forty-one species of Decapoda were used in the multivariate analysis. The analysis indicated that sediment texture (phi) and bottom temperature were the main factors correlated (p < 0.05) with the spatial and temporal abundance of the species. Considering the study region as faunal transition zone, including a mixture of species of both tropical and subantarctic origin, the species responded differently to environmental factors, mainly temperature. It is conceivable that the decapods adjust their distribution according to their intrinsic physiological limitations, possibly as a result of the available resources.

Highlights

Benthic communities have received much attention in recent years, mainly concerning ecological descriptions of coastal areas, as such investigations are fundamental in assessing possible environ mental impacts (Bertini et al 2010)
According to Boschi (2000), the southwestern Atlantic Ocean can be divided into two provinces based on the distribution of decapod crustaceans: the Argentinian Province, which includes the coastal waters of Patagonia, Argentina, Uruguay and Brazil; and the Brazilian Province, which occupies a large extent of the tropical and subtropical coast of northern and northwestern Brazil, French Guiana, Suriname, Guyana and a small part of Venezuela
Our results showed that the abundance and distribution of decapod species depend on a complex of factors, mainly sediment texture and bottom-water temperature

Summary

Introduction

Benthic communities have received much attention in recent years, mainly concerning ecological descriptions of coastal areas, as such investigations are fundamental in assessing possible environ mental impacts (Bertini et al 2010). Among the such as the shrimps Farfantepenaeus brasiliensis (Latreille, 1817) and F. paulensis (Pérez-Farfante, 1967), Litopenaeus schmitti (Burkenroad, 1936), Xiphopenaeus kroyeri (Heller, 1862), Artemesia longinaris Bate, 1888 and Pleoticus muelleri (Bate, 1888) (Costa et al 2004, Castro et al 2005, Castilho et al 2007). This region is a transition area between the two provinces characterized by processes of mixing and instability of the water masses (Boschi 2000), with a mixture of faunas of both tropical/subtropical and temperate origin

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