CONICET | Buscador de Institutos y Recursos Humanos

The golden mussel Limnoperna fortune (Dunker, 1857), is an aggressive invasive continental species recorded for the first time in 1991 on the southern coast of the Río de la Plata, Argentina. The objective of this project is to provide information about the gametogenesis and the reproductive cycle of the invasive mussel L. fortunei. Specimens were collected monthly at Rio de la Plata (34°29´S, 58°28´W: Buenos Aires, Argentina) during low tide. Small portion of the mantle tissue were fixed in Bouin solution, dehydrated and embedded in resin for histological analysis. Based on histological observations, the gametogenic cycle was classified according to five stages of gonadal development: early development, late development, mature, spent and recovering. During early development the ovary was characterized by the presence of oogonia (average diameter of 30 µm) and previtellogenic oocytes while male tubules were comprised mostly of spermatocytes and few spermatids. As maturation advances the ovarian follicle and spermatic tubules increases in size, and few vitellogenic oocytes and sperm were observed, respectively. The ovary was considered to be mature when is full of yolk containing vitellogenic oocytes measuring > 60 µm and testis was full of spermatozoa. Gonads were considered spent when the follicles and tubules underwent a generalized pattern of size reduction and most oocytes and sperm were released. The recovering state was characterized by empty follicles and tubules and signs of degradation were apparent. Males remained mature during almost all the study period with partial gametic emission throughout the year. Females were in developing stages along almost the entire year and showed several spawning periods during fall-winter (April-July), spring (September-November) and summer (February ?March).