Population dynamics and reproductive traits of the ornamental crab Porcellana sayana: implications for fishery management and aquaculture

Abstract

We report on the population dynamics and reproductive traits of an ornamental crus- tacean, the spotted porcelain crab Porcellana sayana. Reproductive biology was examined be - tween January 1998 and December 1999 at 3 different bays off Ubatuba, southeastern Brazil. The growth curves for males and females are described by the equations carapace width at age t (CWt) = 9.42 (1 � e �0.0085(t � 0.1972) ) and CWt = 8.35 (1 � e �0.0097(t � 0.5411) ), respectively. Males and females of P. sayana grew at similar rates and attained similar average and final body sizes. Longevity was estimated to be 1.48 yr in males and 1.3 yr in females. Reproduction was continuous but with dis- similar intensity during the study period. A reproductive peak during the warm austral spring and summer seasons was evident during 1999, but no obvious reproductive seasonality was detected during 1998. The estimated CW at first maturity in P. sayana, based on the 5 smallest ovigerous females captured during each season, varied between 4.72 mm (summer 1999) and 5.69 mm (win- ter 1999), with an average of 4.98 mm (±0.37 SD). Recruitment intensity appears to be episodic and varied haphazardly in P. sayana. Sex ratio did not differ significantly from a 1:1 ratio during most of the seasons. The information generated in this study needs to be considered in assessing stocks and establishing sustainable management plans for P. sayana in the Caribbean, Gulf of Mexico, and western Atlantic.