ABSTRACT
Studies on natural communities are essential for a correct interpretation of the disturbing events, either natural or anthropic. Many species which are not the target of fisheries are captured in the shrimp fishery. Such fact is attributed to the non-selective fishery device used (double-rig trawl), that destabilizes the benthic community. This study provides a landscape on the crustacean decapods community, captured more than 20 years ago by means the shrimp fishery of the X. kroyeri (sea-bob shrimp) at the northern littoral of São Paulo. Samples were collected monthly from November/1988 to October/1989 at the Fortaleza bay. A total of 20377 specimens of 44 species were obtained. The most abundant was X. kroyeri with 13206 individuals. The higher values of diversity index (Shannon-Wiener) were obtained in the sites II and V, which are fishery natural exclusion areas. Our results show that the decapod diversity can be affected in those areas in which the fishery activity is more intense.(AU)
Estudos sobre as comunidades são essenciais para uma interpretação adequada dos eventos perturbadores, sejam eles antrópicos ou não. Na pesca camaroneira, muitos crustáceos sem valor econômico são capturados. Tal fato é atribuído ao uso de um apetrecho de pesca não seletivo (rede double-rig), tornando a pesca uma atividade desestabilizadora das comunidades bentônicas. Este estudo apresenta um panorama sobre as espécies de crustáceos decápodes capturados na pesca de Xiphopenaeus kroyeri (camarão-sete-barbas). As coletas foram realizadas no período de novembro/1988 a outubro/1989 na Enseada da Fortaleza, litoral norte paulista. Foram coletados 20.377 indivíduos pertencentes a 44 espécies, das quais a mais abundante foi X. kroyeri com 13.206 indivíduos. Os maiores valores de índice de diversidade (Shannon-Wiener) foram observados nos pontos amostrais II e V, que correspondem a áreas de exclusão natural de pesca. Este estudo aponta que, em locais onde a atividade pesqueira é mais intensa, a biodiversidade pode ser afetada.(AU)
Subject(s)
Animals , Decapoda , Fisheries , Brachyura , Anomura , PenaeidaeABSTRACT
Studies on natural communities are essential for a correct interpretation of the disturbing events, either natural or anthropic. Many species which are not the target of fisheries are captured in the shrimp fishery. Such fact is attributed to the non-selective fishery device used (double-rig trawl), that destabilizes the benthic community. This study provides a landscape on the crustacean decapods community, captured more than 20 years ago by means the shrimp fishery of the X. kroyeri (sea-bob shrimp) at the northern littoral of São Paulo. Samples were collected monthly from November/1988 to October/1989 at the Fortaleza bay. A total of 20377 specimens of 44 species were obtained. The most abundant was X. kroyeri with 13206 individuals. The higher values of diversity index (Shannon-Wiener) were obtained in the sites II and V, which are fishery natural exclusion areas. Our results show that the decapod diversity can be affected in those areas in which the fishery activity is more intense.
Estudos sobre as comunidades são essenciais para uma interpretação adequada dos eventos perturbadores, sejam eles antrópicos ou não. Na pesca camaroneira, muitos crustáceos sem valor econômico são capturados. Tal fato é atribuído ao uso de um apetrecho de pesca não seletivo (rede double-rig), tornando a pesca uma atividade desestabilizadora das comunidades bentônicas. Este estudo apresenta um panorama sobre as espécies de crustáceos decápodes capturados na pesca de Xiphopenaeus kroyeri (camarão-sete-barbas). As coletas foram realizadas no período de novembro/1988 a outubro/1989 na Enseada da Fortaleza, litoral norte paulista. Foram coletados 20.377 indivíduos pertencentes a 44 espécies, das quais a mais abundante foi X. kroyeri com 13.206 indivíduos. Os maiores valores de índice de diversidade (Shannon-Wiener) foram observados nos pontos amostrais II e V, que correspondem a áreas de exclusão natural de pesca. Este estudo aponta que, em locais onde a atividade pesqueira é mais intensa, a biodiversidade pode ser afetada.
Subject(s)
Animals , Anomura , Brachyura , Decapoda , Fisheries , PenaeidaeABSTRACT
Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.
ABSTRACT
Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.
ABSTRACT
Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.