Short-term fluctuations in bivalve larvae compared with some environmental factors in a coastal lagoon (South Portugal)

Luis M.Z Chícaro,M Alexandra Chícharo

doi:10.3989/scimar.2000.64n4413

Abstract

In this study, short-term fluctuations in bivalve larvae were compared with some triggering factors for a period of sixteen months. Data on the abundance of planktonic larvae, collected two to three times a week were related to water temperature, salinity, wind velocity, tidal amplitude and chlorophyll a. Higher densities of planktonic bivalve larvae were caught between May and August, but intense fluctuations in abundance were observed. Planktonic bivalve larvae of eighteen taxa were identified. Larvae of Mytilus galloprovincialis, Cerastoderma edule, Ruditapes decussates and Venerupis spp. were the most abundant. The seasonal fluctuations of bivalve abundance seem to be controlled by temperature, the major factor in the timing of the reproduction of bivalves. Nevertheless, advection may be also a key factor during the planktonic life of bivalve species in coastal systems, such as the Ria Formosa.

Highlights

The Ria Formosa has a long tradition of bivalve harvesting, especially Ruditapes decussatus and Cerastoderma edule, contributing 90% of Portuguese production
Seasonal and annual observations of the occurrence and abundance of bivalve larvae in the plankton have been made by a few authors, such
General knowledge of bivalve larvae ecology will allow a better understanding of the environmental processes that determine the magnitude of bivalve recruitment

Summary

Introduction

The Ria Formosa has a long tradition of bivalve harvesting, especially Ruditapes decussatus and Cerastoderma edule, contributing 90% of Portuguese production. From the perspecSHORT-TERM FLUCTUATIONS IN BIVALVE LARVAE 413 tive of supply-side ecology, the importance of larval abundance for the recruitment of benthic marine invertebrates is a determining factor in structuring benthic marine communities (Gaines and Roughgarden, 1985; Minchinton and Scheibling, 1991; Miron et al, 1995). This approach has been widely overlooked by benthic and planktonic ecologists

Objectives

Methods

Results

Discussion

Conclusion