Effects of low and high salinity regimes on seasonal gametogenesis of the ribbed mussel Geukensia granosissima in coastal Louisiana, USA

Abstract

ABSTRACT: The environmental controls on the reproductive timing of bivalves need to be better understood and documented in order to predict the potential consequences of a changing environment on bivalve populations. In order to determine the potential impacts of shifting salinity and temperature regimes along the northern Gulf of Mexico, the seasonal timing of gametogenesis in the Gulf estuarine ribbed mussel Geukensia granosissima was examined across a salinity gradient in south Louisiana, USA, from July 2011 through October 2012. Ten mussels were randomly sampled monthly from low (~7) and moderate (~17) salinity marsh sites in south Louisiana and histologically processed to determine the seasonal progression of gametogenesis. Mussels at both sites showed an extended period of maturity from early spring through late fall, when temperatures remained above 20°C. Salinity affected the extent and timing of sexual maturity in the Gulf estuarine ribbed mussel, suggesting that changes in salinity regimes may impact long-term population dynamics.