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We investigated the relative growth and sexual maturity (gonadal and morphometric) of Libinia spinosa. Crabs were sampled at Ubatuba from January to December 2000, using trawls. Based on allometric growth, males were grouped into juveniles (MJ), adolescents (MAd) and adults (MA) based on the relationship CPL (major cheliped propod length) vs. CW (cephalothorax width), all with positive allometric growth. For females, the relationship AW (abdomen width) vs. CW allowed segregating juveniles (FJ) from adults (FA), with positive allometric growth for FJ but isometric growth for FA. The morphometric maturity evidenced for MAd varied from 33.7 mm to 34.5 mm and for MA and FA. The size at which 50% of individuals reach the morphometric sexual maturity was L50 = 50.1 mm for males and L50 = 37.3 mm for females. Gonad maturity was L50 = 33.7 mm for males and L50 = 36.9 mm for females. Through relative growth analyses, we identified an adolescent male group (prepuberal phase). These individuals presented mature gonads, enabling them to copulate with females. These adolescent males may reproduce while avoiding competition with adult males, as it happens in other species of Majoidea that present more than two morphotypes in the population. [ABSTRACT FROM AUTHOR]

Artemesia longinaris was analyzed here with respect to reproductive period, recruitment and sexual maturity. Samples were carried out in five transects, monthly, from November 2008 to October 2009, at Fortaleza Bay, north coast of the State of São Paulo, in Brazil, in a region recently decreed as a Marine Protected Area. In total, 1173 individuals were captured: 198 juveniles, 97 rudimentary females, 485 breeding females and 409 adult males. Breeding females and juveniles appeared seasonally and their abundances were positively corelated with bottom water salinity and temperature. The female size at the onset of sexual maturity was estimated as 13.29 mm of carapace length. Our results indicated that Fortaleza Bay can be considered an appropriate place for the reproduction of A. longinaris during summer, because the environmental conditions there in this period are favourable. We suggest that the fishing ban period should be adequate to take into account the reproductive behaviour of other shrimp species, such as A. longinaris, since it is currently based only on the recruitment of species of Farfantepenaeus. [ABSTRACT FROM AUTHOR]

Upwelling areas are among the most productive ecosystems on the planet, influencing the biology of marine organisms. This study investigated the population dynamics of the shrimp Artemesia longinaris in two regions in southeastern Brazil, one inside (Macaé—Rio de Janeiro State) and one outside (Ubatuba—State of São Paulo) the Cabo Frio upwelling area. The aim was to verify the influence of the upwelling phenomenon on the abundance, growth, longevity, size of sexual maturity, and reproductive period of the species. In total, 188,902 individuals were captured at Macaé and 3,461 at Ubatuba. Individuals captured at Macaé showed larger maximum size, higher longevity, and slower growth rate, besides reaching sexual maturity at larger sizes than at Ubatuba. Continuous reproduction was observed in both regions, with juvenile recruitment peaks in spring and summer. Local conditions observed at Macaé were influenced by the Cabo Frio upwelling zone, characterized by productive and cooler waters that are around 20°C during most of the year. The upwelling phenomenon is probably the main factor influencing the population parameters studied here, changing the geographic patterns previously observed for the variation of these parameters in A. longinaris. [ABSTRACT FROM AUTHOR]