Survival rate and age estimation of the Fiddler Crab, Uca lactea (De Haan, 1835) (Decapoda, Brachyura, Ocypodidae)

Three different methods were employed to estimate the annual survival rate of adult crabs, Uca lactea. A study of the number of burrows showed an average value of 70.5%. From the change of population density in a habitat, it was estimated to be 73.5% in males and 81.6% in females. A total of 499 males and 437 females were put in cages for one or two years in another habitat. The survival rates of those were 84.4% for males and 76.2% for females. No difference in survival rate by body size was encountered. The annual growth decreased with increasing crab size. The estimated CW of two- and seven-year-old males is 14.34 mm and 19.53 mm, respectively. In females, these values are 13.24 mm and 17.35 mm. From the existence of very large individuals in natural populations and the average survival rate calculated, the maximum life span is deduced to be seven years or more.