George Olavo

Fish Biodiversity of the Vitória-Trindade Seamount Chain, Southwestern Atlantic: An Updated Database

Despite a strong increase in research on seamounts and oceanic islands ecology and biogeography, many basic aspects of their biodiversity are still unknown. In the southwestern Atlantic, the Vitória-Trindade Seamount Chain (VTC) extends ca. 1,200 km offshore the Brazilian continental shelf, from the Vitória seamount to the oceanic islands of Trindade and Martin Vaz. For a long time, most of the biological information available regarded its islands. Our study presents and analyzes an extensive database on the VTC fish biodiversity, built on data compiled from literature and recent scientific expeditions that assessed both shallow to mesophotic environments. A total of 273 species were recorded, 211 of which occur on seamounts and 173 at the islands. New records for seamounts or islands include 191 reef fish species and 64 depth range extensions. The structure of fish assemblages was similar between islands and seamounts, not differing in species geographic distribution, trophic composition, or spawning strategies. Main differences were related to endemism, higher at the islands, and to the number of endangered species, higher at the seamounts. Since unregulated fishing activities are common in the region, and mining activities are expected to drastically increase in the near future (carbonates on seamount summits and metals on slopes), this unique biodiversity needs urgent attention and management.

Indirect signals of spawning aggregations of three commercial reef fish species on the continental shelf of Bahia, east coast of Brazil

Lutjanus analis (Cioba), Lutjanus Jocu (Dentao) e Mycteroperca bonaci (Badejo) sao peixes recifais de alto valor comercial e estao entre os principais recursos explotados na costa da Bahia. Estas especies compartilham o habito de formar agregacoes reprodutivas transientes, previsiveis no tempo e no espaco, o que as torna particularmente vulneraveis. O presente estudo objetivou obter indicadores indiretos de periodos e locais de possivel ocorrencia de agregacoes reprodutivas destas especies, a partir da analise exploratoria de dados de captura e esforco de pesca disponiveis para a regiao do Baixo Sul da Bahia. Foram analisados dados de desembarques da pesca de linha monitorados em 12 localidades da regiao, com registros de captura de Cioba (1320 desembarques), Dentao (654) e Badejo (1162). Foi desenvolvida uma estrategia de analise exploratoria da variacao mensal e distribuicao individual das CPUE por viagem. Os resultados indicaram ocorrencia de agregacoes em 26 sitios especificos, observando valores de abundância relativa muito acima das medias anuais, tanto no periodo de primavera/verao, como no de outono/inverno. As ocorrencias dessas capturas foram validadas junto aos pescadores responsaveis por tais pescarias. Estudos adicionais sao necessarios para confirmar a atividade de desova nesses locais. Analise da variacao inter-anual das CPUE sugere tendencia de declinio na abundância relativa do Badejo e da Cioba, possivelmente associada a pesca nao controlada sobre agregacoes reprodutivas.

Notas sobre a alimentação de syacium micrurum ranzani, 1842 actinopterygii: paralichthyidae) no talude continental ao largo da Bahia (nordeste do brasil), oceano Atlântico Ocidenta

Informations about biology of 100 specimens of Syacium micrurum Ranzani, 1842 (Actinopterygii: Paralichthyidae) from Bahia state (northeastern Brazil, Western Atlantic Ocean) are presented. Total lengths varied between 80,0 mm and 217,0 mm. The food of S. micrurum consists mainly of crustaceans Brachyura (crabs) and Dendrobranchiata (shrimps) but also in minor proportions of Cephalopoda, Teleostei, Polychaeta and other groups of crustaceans.