ABSTRACT. Associations of fishes in the coastal region of Itaipu, Niterói. The coastal region of Itaipu, Rio de Janeiro forms a partially sheltered sound, protected by three islands, but still maintaining full communication with the open sea. The sound also receives fresh water input from the Itaipu-Piratininga lagoon system, constituting an area of intense artisanal fisheries. Using data from monthly monitoring of the artisanal fisheries (beach seining, gill netting and hand lining), experimental surf zone beach seine surveys, underwater visual census (Menina, Mãe, and Pai islands), and a multisampling experiment at Itaipu Lagoon, we elaborated a list of fish species occurring in the region, observing their connectivity with different local habitats, including the sound, rocky reefs, the surf zone and Itaipu Lagoon. We identified 183 species including 26 Elasmobranchii, grouped in 13 families, and 157 Actinopterygii grouped in 63 families. The artisanal beach seining caught the greatest number of species (112), followed by the gill netting (94) and hand lining (35). The surf zone beach seining ("picaré") yielded 49 species (8 exclusive) represented mostly by juvenile fish and species of little economic importance. Visual censuses resulted in 41 species identified, with 21 exclusive and most of them cryptic. Within the Itaipu lagoon, 46 species were recorded, 18 exclusive and of occasional occurrence. Cluster analysis including 106 non exclusive species resulted in the formation of eight different groups. Groups A and B were composed by species captured exclusively by the artisanal fisheries within the sound, and included species of commercial interest. Group C included species occurring in the fisheries whose juveniles are found in the surf zone. Group D classified species of common occurrence in the fisheries and the islands. Group E was represented by species shared by the fisheries and Itaipu lagoon (mullets, mojarras, herrings). Species from group F were absent in the islands, those from group G in the lagoon, and those from group H were common to all areas considered. Compared with other coastal areas in southeastern Brazil, Itaipu represents an important concentration area for fish biological diversity and biomass, yielding species associations and connectivity between the different local habitats. KEYWORDS.Itaipu, species list, fishes, artisanal fisheries, habitat connectivity. RESUMO.A região costeira de Itaipu, Rio de Janeiro é guarnecida por três ilhas, formando uma enseada semi-abrigada porém com ampla comunicação com o mar. Esta enseada recebe o aporte de águas do complexo lagunar Itaipu-Piratininga, além da influência de massas d'água oceânicas, constituindo uma área de intensa atividade pesqueira artesanal. Utilizando-se dados provenientes do monitoramento mensal da pesca artesanal (arrastos-de-praia, redes de emalhe e linha de mão), de arrastos experimentais em zona de arrebentação, censos visuais sub-aquáticos (ilhas da Menina, Mãe e Pai) e um experimento multiamostral na lagoa de Itaipu, elabor...
A B S T R A C TStudies on the feeding preferences of marine herbivores are very important for our better understanding of the biology and the ecological role of these organisms. Members of the family Epialtidae are usually herbivores that mask themselves with pieces of seaweed and other materials to avoid predation. In order to better understand the mechanisms of food and decorating choices of the decorator crab Acanthonyx scutiformis, two multiple-choice feeding assays were performed using fresh seaweeds and artificial food containing crude extracts of the four seaweeds Osmundaria obtusiloba, Plocamium brasiliense, Sargassum sp., and Dictyota menstrualis, offered simultaneously to this crab species. In both assays the seaweed most consumed was O. obtusiloba, followed by P. brasiliense and Sargassum sp., while D. menstrualis was the least consumed. It is suggested that A. scutiformis is a generalist feeder, but with some preference for the perennial red seaweed O. obtusiloba and the chemically-defended seaweed P. brasiliense. Decorating behavior observations revealed the preferences of A. scutiformis by P. brasiliense. This decorating behavior can be interpreted as a mechanism to avoid generalist predators, since feeding and decorating preference were not associated and the crab used only small pieces of chemically defended algae. R E S U M OEstudos sobre preferência alimentar de herbívoros marinhos são muito importantes para o melhor entendimento da importância biológica e ecológica destes organismos. Caranguejos majídeos são usualmente herbívoros que se camuflam com pedaços de macroalgas e outros materiais para evitar a predação. Para entender melhor os mecanismos de escolha de alimento e decoração do caranguejo decorador Acanthonyx scutiformis, foram realizados dois ensaios de múltipla escolha usando macroalgas frescas e alimentos artificiais contendo extratos brutos das macroalgas Osmundaria obtusiloba, Plocamium brasiliense, Sargassum sp. e Dictyota menstrualis, oferecidas simultaneamente a esta espécie de caranguejo. Em ambos ensaios, a macroalga mais consumida foi O. obtusiloba, seguida por P. brasiliense e Sargassum sp., enquanto D. menstrualis foi menos consumida. É sugerido que A. scutiformis é um consumidor generalista, mas com alguma preferência pela macroalga vermelha perenial O. obtusiloba e a macroalga quimicamente defendida P. brasiliense. Observações sobre o comportamento decorador revelaram a preferência de A. scutiformis por P. brasiliense. Este comportamento decorador pode ser interpretado como um mecanismo para evitar predadores generalistas, uma vez que as preferências por consumo e decoração não foram relacionadas e o caranguejo usou somente pequenos pedaços de algas quimicamente defendidas.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.