Limnetica 34
Population dynamics of the native apple snail Pomacea flagellata (Ampullariidae) in a coastal lagoon of the Mexican Caribbean
Apple snails Pomacea flagellata inhabit tropical and subtropical freshwater environments and are of ecological and economic importance. To evaluate the population dynamics of P. flagellata, monthly samples were collected from Guerrero Lagoon (Yucatán Peninsula) from June 2012 to May 2013. The measured environmental variables did not differ significantly among the sampling stations. However, salinity was lower during the rainy season, and the temperature was lower during the north season (i.e., the season dominated by cold fronts). The snails were more abundant during the rainy season, and they were restricted to the portion of the lagoon that receives freshwater discharges. The snails ranged from 4 to 55 mm in size, with a maximum estimated length of L∞=57.75 mm and a growth rate of K=0.68 y-1 (the abbreviation “y” means “year”) with a seasonal oscillation; the lowest growth rate occurred in early December. Longevity was estimated at 3.3 y and the mortality rate at 1.89 y-1. Mean biomass was 124.65 g/ ha, with a somatic production of 178.32 g ha-1 y-1 and a turnover rate of 1.43 y-1. We conclude that the abundance of P. flagellata was very low and could be influenced by salinity. Moreover, the population parameters estimated for P. flagellata are the lowest reported in the literature for a freshwater snail. This is the first study of a population of Pomacea in a brackish environment.
