BIOMETRIC RELATIONSHIP ANALYSIS OF THE WE T WEIGHT BY CARAPACE WIDTH TO THE SWIMMING CRAB ARENAEUS-CRIBRARIUS (LAMARCK, 1818) (CRUSTACEA, BRACHYURA, PORTUNIDAE)

The biometric relationship between the weigth and the carapace width i n the swimming crab A. cribrarius was compared with the results from o ther portunid crabs studied previously. During November/1988 to Octobe r/1989, a total of 403 specimens (189 males and 214 females) were coll ected with otter-trawl nets in north coast of the Sao Paulo State, Bra zil. The animals were measured (carapace width excluding lateral spine s = LC! and weighed (wet weight = PE). The empiric points of this rela tion were fit according to the power function (Y = a.X(b)) for each se x, maturation phases and total of individuals. The relation PE x LC in dicates that the mole's growth changes during the ontogenesys from iso metric (in juvenile phase) to allometric positive (in adult phase). Fo r the females the growth is isometric in the two phases. The weight gr ows in a higher proportion than the carapace width variable (allometri c positive growth). The data can be grouped in a single equation (PE = 7.85.10(-5).LC(3.14)) for the convertion between the variables there was a greater similarity between the equations obtained far each sex. In spite of this, the males present the fattening grade value (''a'') slightly higher than that of the females, possibly because of the grea ter size reached in its devellopment. The mean weight of the males is greater than the females one (p < 0.01). In the range 80 proves 90mm t he males were more abundant, probably due to the females terminal ecdy sis is near this size. The females only have the mean weight greater t han the males in the 60 proves 70mm range (p < 0.01) when the puberty molt occurs and they present morphological changes in their reproducti ve system.