Reproduction and imposex in the edible snail Adelomelon ancilla from northern Patagonia, Argentina

PABLO E. PENCHASZADEH; CARLOS SÁNCHEZ ANTELO; SOLEDAD ZABALA; GREGORIO BIGATTI

MARINE BIOLOGY

SPRINGER

Año: 2009 vol. 156 p. 1929 - 1939

0025-3162

The edible volutid snail Adelomelon ancilla occurs on the Argentine coast and may have the capacity to serve as source of support for local fisheries. However, knowledge of its reproduction is lacking. Over 3 years (from September 2000 to July 2004) we studied the oviposition at Golfo Nuevo, Patagonia by diving. Monthly collections were performed to examine gonadal stages histologically during 2002 to 2003. Gamete development stages corresponded with the expected period for oviposition occurring from July to November, a time of increasing daylength. Oviposition also took place in March when water temperature attained a maximum of 18ºC. Following the spawning period, remaining gametes were resorbed in both sexes. Males contained sperm throughout the year, parasperm and eusperm forms were found within the same acinus. Oocytes ranged from 20 to 240 µm in diameter during oogenesis. Females commenced laying egg capsules from a shell height of 114 mm. Reproduction is compared with other fishable volutids snails from the Argentine shelf, and suggests the need to apply certain fishing restrictions if the resource begins to be utilized commercially. The imposex condition was found in snails from some shipping areas. The frequency of this condition declined with distance from the port.