Using modal progression analysis for indirect age determination, growth of the blue crab Callinectes sapidus Rathbun, 1896 was estimated for two fishery areas of the Patos Lagoon. Individuals were sampled using a conventional gear of the artisanal fishery - trawl net - from February, 2005 to March, 2006 in 'Saco da Mangueira' and 'Saco do Arraial'. A total of 2,609 (1,194 males and 1,416 females) animals was caught. Growth curves were estimated using the von Bertalanffy growth model. Estimated growth curves were validated in the light of the life cycle and biological characteristics of the species. Asymptotic width (CWmax) was fixed in all analyses (162.71mm, ± s.d.=3.10 and 157.78mm, ± s.d.=5.45 for males and females respectively), as this value is an average of the maximum lengths of crabs caught in the estuary over a period of 20 years. Growth parameters and longevity were estimated for males ('Saco da Mangueira', K=0.0039/day; t o=-6.07; 1195 days; 'Saco do Arraial', K=0.0041/day; t o=-5,84; 1102 days) and females ('Saco da Mangueira', K=0.0040/day; t o=-6,22; 1153 days; 'Saco do Arraial', K=0.0039/day; t o=-5.91; 1181 days). Growth curves estimated in the present investigation indicate that the minimum legal size (120mm) is attained around the first year of life.
Bertalanffy; Brachyura; blue crab; Patos Lagoon; trawl net
