Life History ofEmerita analoga(Stimpson) (Anomura, Hippidae) in a Sandy Beach of South Central Chile

Emerita analoga(Crustacea, Anomura, Hippidae) is a characteristic species of the swash zone of temperate sandy beaches of the Eastern Pacific. To analyse the reproductive biology and population dynamics of a population located in south central Chile, monthly samples were collected from an exposed sandy beach (Mehu?n,c. 39°S). Samples were taken from June 1989 through May 1991, and between June 1992 and May 1993, from the uppermost beach levels and the lowest level of the swash zone. The highest abundances ofE. analogaoccurred during the late spring-early summer. The highest mean fecundity values occurred in winter and summer, and the lowest during spring. The size at which females reach sexual maturity was found to be 16-17 mm (about 12 months after recruitment). Two recruitment peaks were found: one during early autumn, and the other during spring. Growth analyses showed that growth rates of females were higher than those of males for the three annual periods analysed. It is concluded that differences in size at sexual maturity and in growth rates can explain sexual dimorphism in adultE. analogain south central Chile.