Distribution and growth in adults of Macrobrachium acanthurus Wiegmann, (Decapoda, Palaemonidae) in a tropical coastal lagoon, Brazil

Edélti Faria Albertoni, Cleber Palma-Silva, Francisco de Assis Esteves
2002 Revista Brasileira de Zoologia  
MacrobrachiwlI acalllhurlls Wiegmann, 1836 is a Palaemonidae commonly found in Brazilian coastal environments. At Imboassica lagoon, located in the north of the State of Rio de Janeiro, it is found in two stages of its life cycle: as larvae and as reproductive adults. This work had as its goal the evaluation of adults distribution , estimating the weight/length relationship and the condition factor of these adults. After sampling in two regions of the lagoon, one interior and another closer to
more » ... another closer to the ocean, we verified that females are found in a greater propol1ion close to the ocean. and males are found in greater number in the innermost region, amidst the aquatic macrophytes , suggesting that the fecundation takes place in this lasi area and the females then travel to the area closer to the ocean to spawn. Total and carapace weight/length relationship exhibited differences between males and females, presenting positive allometric growth. The relative growth of the cephalotorax related to total length showed that it correspond to 53% of the total length in females , and 50% in males . The average condition factor was significantly lower than the expected pattern, demonstrating that the species does not find ideal conditions in the lagoon. T his may be attributed to the migration of the adults, to the spawning and/or to the impact caused by the frequent sandbar openings that took place at Imboassica lagoon during the studied period. KEY WORDS. Palaemonidae, Ma crobrachiul11 (lean/hurl/s, coastal lagoon, weight/length relationship , condition factor The genus Macrobrachium Bate, 1868 encompasses species that thrive in lotic and lentic env ironments, being found in several aq u atic systems in Brazi l, both in freshwater and in mesohaline environments (COELHO & RAMOS-PORTO 1985; VALENTI 1985) . Studies focusing on different ecological and biological aspects of several species have been executed in some areas in Brazil , and among them we may under li ne the works
doi:10.1590/s0101-81752002000600006 fatcat:sbm5jtx7frbthfqsg45trwz66a