Growth and Reproduction of Pomacea patula catemacensis Baker, 1922 (Gastropoda: Ampullariidae) When Fed Calothrix sp. (Cyanobacteria)

The freshwater snail Pomacea patula catemacensis is a fishing resource that is endemic to Lake Catemaco, Veracruz, Mexico. Due to overfishing and other anthropogenic factors, its capture has decreased in recent years. Various research projects have been conducted to support its recovery, although many aspects of its basic biology are as yet unknown. This study evaluated how the snail's growth and reproduction are affected when it is fed the cultivated cyanobacteria Calothrix_-sp. (C), in comparison to a diet elaborated with pellet-shaped carp food (P). Experimentation was carried out in two closed-recirculation systems (RS1 and RS2) for a period of 181 d. In RS1, 80 3-mo-old juveniles were distributed, as opposed to 144 6-mo-old adults in RS2. In RS1, the weight gain was 3.98 g with diet C and 3.44 g for juveniles fed P; 74 and 68 egg masses were produced in RS1 with C and P, of which 64.9 and 67.7% turned out to be fertile, respectively. In RS2 average weight increase was 0.74 and 1.14 g for C and P; 117 and 92 egg masses were produced, of which 39.3 and 28.3% were fertile for adults fed C and P, respectively. The number of organisms that hatched was independent of egg mass weight. Fecundity was linked to snail size, and diet had a significant effect on fertility in each system. It was established that, in general, Calothrix was superior to pellet carp food, as the former demonstrated that it can be efficiently consumed as food for P. patula catemacensis in laboratory conditions.