Seasonal changes and energy allocation in the edible snail Zidona dufresnei (Caenogastropoda, Volutidae)

Abstract

Energy acquisition and allocation between the somatic compartments are essential for the ecological success of an organism. The seasonal pattern of energy allocation among the diferent organs was evaluated in the snail Zidona dufresnei. The somatic indexes, energy density and energy content of the gonads, digestive gland, foot, and secondary sexual glands of Z. dusfresnei. The lowest foot index (FI), energy density and energy content were found in winter. The high digestive gland index (DI) and energy content (ECDIG) observed in spring likely coincide with the peak of productivity. The male’s gonads did not show seasonal energetic variation, although the gonadosomatic index (GI) of males was lower in summer than in other months. The mass and energy content of the albumen and capsule glands exhibited a decreasing pattern from spring to winter. The foot is suggested as the main energy reservoir in Z. dufresnei, the digestive gland as an energy reservoir that contributes to the gonadal maturation, whereas the energy of the capsule and the albumen glands contributes to the spawning. This study highlights seasonal variations in the energy content of the foot (edible compartment) and the signifcance of secondary sexual glands in understanding the bioenergetics of Z. dusfresnei and ofspring ftness. These fndings should be taken into consideration in fsheries management decisions for this ecologically and commercially important species.