Sexual differentiation and size at first maturity of the invasive mussel Perna viridis (Linnaeus, 1758) (Mollusca: Mytilidae) at La Restinga lagoon (Margarita Island, Venezuela).

GREGORIO BIGATTI, PATRICIA MILOSLAVICH, AND PABLO E. PENCHASZADEH,

AMERICAN MALACOLOGICAL BULLETIN

AMER MALACOLOGICAL SOC, INC

Año: 2005 vol. 20 p. 65 - 69

0740-2783

ABSTRACT The Asian green mussel was first recorded in the Americas in 1992 at Trinidad Island. In 1995 it was observed in the mainland coast of South America at Sucre State (Venezuela) and in 1998 at La Restinga lagoon, Margarita Island (Venezuela). In this work we studied the size at sexual differentiation and the size at first maturity of Perna viridis from La Restinga lagoon by histological sections, and determined whether this mussel population was reproductively active. One hundred specimens of P. viridis between 8 mm and 91.2 mm in total shell length were examined. Sexual differentiation started at 20 mm with incipient follicular formation. No gonad development was observed in individuals smaller than 18 mm. Specimens larger than 25.0 mm had well-developed gonads at different stages of maturation. Size at first maturity is discussed in relation to other localities. We conclude that the population of  P. viridis  at La Restinga lagoon is reproductively active and hypothesize that given that the lacunar  mangrove system is permanently open to the sea, larval supply could come either from outside or inside the lagoon, assuring the recruitment of new spat and the dispersion of the species. We discuss the implications of environmental changes resulting from the introduction of this invasive species into the lagoon.