Reproductive cycle of the cholga paleta, Atrina seminuda Lamarck, 1819 (Bivalvia: pinnidae) from Northern Patagonia, Argentina

GASPAR SORIA; MARCELA PASCUAL; VICTOR HUGO FERNANDEZ-CARTES

JOURNAL OF SHELLFISH RESEARCH

NATL SHELLFISHERIES ASSOC

Año: 2002 vol. 21 p. 479 - 488

0730-8000

Atrina seminuda (Bivalvia: Pinnidae) is distributed naturally along the Atlantic coast of America from North Carolina to the Valdés Peninsula. At the San Matías gulf (North Patagonia), its southern distributional limit, it inhabits subtidal areas of fine and coarse sandy bottoms, on depths ranging from 4 to 30 m. The reproductive cycle of a population of A. seminuda was studied from October 1999 to October 2000. Histological samples of gonad tissue were obtained from adult individuals collected at Piedras Coloradas (40º 53´ S, 65º 04´W). Six stages of gonad development were described on the basis of histo-morphological characteristics: indifferent, early active, developing, mature, spawning and spent. This study indicates that A. seminuda exhibits an annual reproductive cycle. Gametogenesis starts at the beginning of autumn and is prolonged during the winter. A high synchronism in maturation and spawning occurs at November and December. The spent stage begins at mid-summer and concludes at the end of that season. Muscle index (MI) fluctuates inversely to the gonad index (GI) along the reproductive season, suggesting that this species uses reserves stored in the adductor muscle for gonadic maturation. A. seminuda is a gonochoric stable species that exhibits, on a 1.05 % of the individuals, two types of  functional hermaphroditism.