SOME ASPECTS OF THE GONADAL CYCLE IN THE ANTARCTIC BIVALVE Laternula elliptica (KING & BRODERIP, 1831).

BIGATTI, G., PENCHASZADEH, P.E. & MERCURI, G.

VIENA, Austria.

Congreso; WORLD CONGRESS OF MALACOLOGY; 2001

ABSTRACT Vitellogenesis and oocyte growth in Laternula elliptica, a common hermaphrodite bivalve living in the soft muddy bottoms of the Antarctic continent, is reported. Facts related with the formation of the gelatinous layer surrounding the oocyte, gonadic development, accumulation of mature oocytes and spawning events are studied through histological evidence. Gonad development was observed at a size of 27 mm, reaching maturity at a size of 49 mm. The vitellogenesis has been found to last seven months, and  storage of  oocytes before spawning has been observed . It has been observed that once sexually mature, the animals remain with sperm cells and oocytes  available during the whole year, suggesting that individuals would be prepared to spawn in any moment, probably depending on environmental conditions. KEY WORDS: Laternula elliptica, Antarctica clams, vitellogenesis, oocytes growth, first