The present study investigated the reproductive biology of the pink shrimp Farfantepenaeus brasiliensis and Farfantepenaeus paulensis captured offshore and at two important fishing grounds, Guanabara Bay and Araruama Lagoon both on the south-eastern Brazil coast. The females’ size at first maturation was 37.90 mm of carapace length (CL) for F. brasiliensis and 41.95 mm of CL for F. paulensis. Both species presented continuous reproduction with two spawning peaks. For F. brasiliensis these peaks occurred during summer and winter and for F. paulensis during summer and autumn. The sex-ratio of the pink shrimp was favourable to the number of females which can be a strategy to guarantee the reproduction.
Callinectes danae and Callinectes ornatus are two Portunidae crabs which are an important portion of the fishing products of Guanabara Bay, but are being discarded by shrimp trawlers along the Brazilian coast. Instantaneous mortality rates Z, M, F and the exploitation rates E for both species and for both sexes were estimated. Total mortality (Z) was estimated by lengthconverted catch curves and natural mortality (M) was based on life history analysis where K and t 0 were parameters of the von Bertalanffy growth function. Fishing mortality rates presented low values of F for males of C. danae and C. ornatus (0.27 and 0.80), but not for the females (3.29 and 16.27). These females exhibited high values of fishing mortality and elevated exploitation rates (0.64 and 0.90). These high values may be a result of intense trawling in the region and/or the migration activity of these species to other coastal areas during the reproductive period, overestimating fishing mortality.
A B S T R A C TDredging and dredge-spoil disposal are among the major problems in coastal management. Many of the scientific contributions concerning the impacts of this practice are based on the study of sessile organisms and subtropical environments. We evaluated changes in the composition and abundance of a fish assemblage resulting from dredging and sediment disposal at the mouth and in the adjacent waters of the Caravelas River on the north-eastern coast of Brazil. Samples were collected in two directly impacted and three adjacent areas. Differences among stations were not significant, but the dredged site had the least diverse station, as expected. The stations farthest from the directly impacted areas apparently were not influenced by the coastal work, thus suggesting localised effects. The contribution of the present study is particularly important because of the study area's proximity to others that have high conservation value such as mangrove forests and coral reefs, and the relevance of the subject given the continuing dredging activity.
R E S U M OA dragagem e descarte de sedimento se destacam como atividades que geram grandes distúrbios aos ecossistemas marinhos e, consequentemente tornam-se um desafio ao manejo e ordenamento costeiro. Grande parte dos estudos que abordam seus impactos é baseada em pesquisas com organismos sésseis e em ambientes temperados, criando uma lacuna no entendimento de seus efeitos sobre a ictiofauna, principalmente nas regiões tropicais. No presente estudo foram avaliadas as alterações na composição e abundância da comunidade de peixes sob influência da dragagem e descarte de sedimento na foz do Rio Caravelas, costa da região Nordeste do Brasil. As amostras foram obtidas em duas estações diretamente afetadas e em três outras áreas adjacentes. Não houve diferença significativa na diversidade média obtida para cada estação, porém a estação correspondente à área dragada apresentou o menor valor dentre as demais. As estações mais afastadas aparentemente não foram influenciadas pelo empreendimento sugerindo efeitos localizados. A contribuição do presente estudo é particularmente importante devido à proximidade com áreas de alto valor de conservação como manguezais e recifes de corais e a relevância do assunto, o qual trata de uma atividade que sugere expansão em vista do desenvolvimento da atividade portuária.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.