In this paper, the fecundity in Macrobrachium acanthurus (Wiegmann, 1836) of the Ribeira de Iguape river (Southern Brazil) (Crustacea, Decapoda, Palaemonidae), is presented. The mean individual fecundity of the population was estimated. Fecundity was related to either length and/or weight. Our data showed that this species presents high fecundity and is thus suitable for comercial culture. The fecundity/length and fecundity/weight relationships obtained are: F = - 14 712 + 2 311,8 L and F = -1493,9 + 798,76

. TH E EFFECT OF STOCKING DENSITY ON MACROBRACHIUM ROSENBERG II (D E MAN) GROWTH CURVES lN EARTHEN PONDS (CRUSTACEA, PALAEMONIDAE). ln this artic\e the length growth curves of Macrobrachium rosenbergii (De Man, 1879) held in different population densities were analysed. Postlarvae prawns were stocked into five 0,02 ha earthen ponds at densities of 4, 8, 12, 16 and 20 ind./m 2 during six months. Forthnightly, the mean total length of animaIs from each pond were obtained by means of random samples. For each population the length growth curves and the instantaneous growth rate expressions were determined. The growth rate and the asymptotic maximum length decreased with the stocking density raised. This effect is greater when the density ranges in low leveIs. The growth decrease can be due to intraspecific competition for life resources and to negative interactions between individuaIs, as aggressive or social behavior, that increase with the increase prawns density. KEY WORDS. Crustacea, Palaemonidae, Macrobrachium rosenbergiJ, ecologyMacrobrachium rosenbergii (De Man, 1879) é conhecido popularmente como camarão da Malásia, gigante da Malásia ou camarão de água doce. Diversos estudos referentes a aspectos de sua biologia foram realizados nas três últimas décadas tornando-se possível e viável economicamente seu cultivo em larga escala. Atualmente, esta é a espécie de camarão de água doce mais utilizada em projetos de carcinicultura em todo o mundo, sendo a única cultivada no Brasil com fms comerciais (VALENTI, no prelo).O crescimento é um dos aspectos do desenvolvimento de um animal e pode ser expresso como o aumento em comprimento, volume ou peso ao longo do tempo (NIKOLSKII, 1969;HARTNOLL, 1982). Resulta de um balanço entre os processos de anabolismo e catabolismo que ocorrem no indivíduo (VONBERTALANFFY, 1938). 1) Trabalho financiado pela FAPESP.

ABSTRACT. ln this paper. femalo Macmhrachilllll corei""". (Linnaeus. 1758) maturation curve. wcight / knglh rdationship. kllgth ano wl.!ight growth curvl!s wcrc stuoieo . Prawns wer.: eaplUreo. hy traps . in Riheira de I~uape river (24°S and 4rW). southan Brazil. There were used 207 females. It was observed that M. cllrcinlls presents several spawnings during its !ife ,ycle and reprodu,tive paiod goes on. ai leasttill six years old. Weighlllength rdalionship can be represented for the equalion W=8.73 E-3 L3.c~. Exprcssions ohtained for length and weight growth curves are L. =21.0 (l_c -o.~9J') aml W, = 190 (l_e· O . 493 ')3.c8. respectively. Asymptotic maximul11 length aml asymptotic maxilllum wcight are nearly allained at six and eight y.:ars 010, rcspectivdy.