Analysis of reproductive strategies of lion’s paw scallop (Nodipecten subnodosus) to regulate gametogenesis in a suspended culturing system in Bahía Tortugas, Mexico

Abstract

The lion’s paw scallop Nodipecten subnodosus supports an important fishery in Northwestern Mexico and represents a target species for aquaculture practices. The reproductive strategy of the species to fuel gametogenesis in a culturing system in Bahia Tortugas (Baja California Sur, Mexico) was investigated during an annual cycle. We used histological and histochemical techniques, as well as a gonadosomatic index and morpho-physiological indices for the digestive gland, adductor muscle and mantle tissue. The response of the species was compared with data previously reported at other localities. Frequencies of gonad developmental stages, oocyte diameter, and lipid index of oocytes indicates that gametogenesis was continuous throughout the year in Bahia Tortugas, with two spawning peaks in July–August 2009 (minor) and December through February (major). Bahia Tortugas is a eutrophic area offering high primary productivity all year round; under these conditions, gametogenesis appears to be regulated by the energy taken from food following an opportunistic strategy. However, the digestive gland index decreased and the mantle tissue and muscle indices increased during the period of maximum gamete growth, suggesting that the species also uses some of its stored reserves to partially fuel gametogenesis (conservative strategy). High incidence of reabsorbing gonads (atresia) likely occurred because of atypical daily variations in water temperature from May through September (12 °C to 38 °C), or stressful conditions in the culturing system in summer. Despite this, the culturing system set in Bahia Tortugas appears beneficial for a prolonged reproduction of N. subnodosus