Space-time distribution of the non-indigenous bivalve Mytilopsis leucophaeta (Conrad, 1831) in estuarine areas of the Capibaribe River, Recife, Pernambuco State

Abstract

This paper describes the distribution and population structure of the non-indigenous bivalve  Mytilopsis leucophaeta along the estuarine gradient in Capibaribe river and compares the density of native species  Mytella charruana with introduced  species  Mytilopsis leucophaeta from March 2007 to May 2008. The densities of the bivalve  M. leucophaeta  and M. charruana varied at each point of the estuary, and we observed that euhaline areas, the density of  M. leucophaeta  and M. charruana were  inversely proportional, thus indicating a competitive interaction between them. The rainy season strongly affects the density of  M. leucophaeta , with reduction or disappearance of the species just after the rainy season, this may be related to pollution  observed along the estuary of the Capibaribe river, since pollution accumulated in its the upper region is transported in large  quantities in winter because during the dry season flow of the river is very poor.  M. leucophaeta is well established in estuarine  areas of Recife, with a continuous and more intensive recruitment in the summer. It was found to be adhered to substrates to form  dense aggregates in intertidal regions, where it competes for space with the native species  Mytella charruana .