Habitat of juvenile Caribbean reef sharks, Carcharhinus perezi, at two oceanic insular marine protected areas in the southwestern Atlantic Ocean: Fernando de Noronha Archipelago and Atol das Rocas, Brazil

Habitat of juvenile Caribbean reef sharks, Carcharhinus perezi (Carcharhinidae), was identified using fishing surveys and capture of immature specimens at two Brazilian insular sites in the southwestern Atlantic Ocean, Fernando de Noronha Archipelago and Atol das Rocas. Standardized sampling at Fernando de Noronha indicated that parturition occurred from February to April and that a wide depth-range (at least 5-30 m) along the insular shelf was used by immature sharks throughout the year. The catch-per-unit effort of C. perezi was significantly higher inside than outside a marine protected area at this location, suggesting that these sharks are more common in pans of the reef least disturbed by human activities. More limited sampling at Atol das Rocas suggested that juvenile C. perezi occurred at similar depths and utilized similar substrate as sharks at Fernando de Noronha. These findings suggest that successful conservation and management of this economically important, protected species will need to include conservation of habitat around insular reef systems. (c) 2006 Elsevier B.V. All rights reserved.

Biology of Isopisthus parvipinnis: an abundant sciaenid species captured bycatch during sea-bob shrimp fishery in Brazil

A pesca de arrasto é o método mais comum de captura de camarão. Esta técnica causa impactos negativos na fauna demersal devido ao grande número de animais que são capturados acidentalmente e que geralmente são devolvidos mortos ao mar. As conseqüências desta metodologia de pesca e os aspectos biológicos das espécies envolvidas são pouco estudados, especialmente no Nordeste do Brasil. Este estudo tem como objetivo mostrar aspectos biológicos de Isopisthus parvipinnis (tortinha) capturada como fauna acompanhante da pesca do camarão sete barbas (Xiphopenaeus kroyeri) na região de Ilhéus, no estado da Bahia, Brasil. Um total de 1290 indivíduos foram capturados em coletas mensais, em três pontos de coleta distintos, de março de 2003 a fevereiro de 2005. O índice de dispersão de Morisita padronizado sugere que a espécie, na área analisada, apresenta uma distribuição agregada. O número de indivíduos variou significativamente entre as estações do ano (p < 0,0001), sendo maior durante o inverno. O comprimento estimado de primeira maturação (L50) foi de 159 mm, sendo que 95% dos indivíduos capturados estavam abaixo deste valor. A razão sexual encontrada foi de 1,5 machos para cada fêmea. Quanto à dieta, foram identificadas 10 categorias alimentares, sendo que Decapoda Dendobranchiata foi a mais importante em freqüência numérica e de ocorrência. Este fato sugere que Isopisthus parvipinnis é uma espécie carnívora, com tendência a carcinofagia, ao menos nos indivíduos jovens.

Feeding habits of the atlantic spotted dolphin, Stenella frontalis, in southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A bio-economic appraisal of pair trawl fisheries off southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analytical procedure for total mercury determination in fishes and shrimps by chronopotentiometric stripping analysis at gold film electrodes after microwave digestion

A method for the total mercury determination in fish and shrimps employing chronopotentiometric stripping analysis on gold film electrodes is described. Fish and shrimp tissues were digested using a microwave oven equipped with closed vessels. We developed a microwave heating program which decomposed all the samples employing diluted nitric acid and hydrogen peroxide. The proposed method was validated by analyzing a certified reference material and then applied for different fish species from fresh water and seawater acquired in local markets of São Paulo city, Brazil. The Brazilian legislation establishes 0.5 and 1 mg per kilogram of fish as upper limit of mercury for omnivorous and predator species, respectively. Except for blue shark tissues, the mercury content was situated below 0.5 mu g g(-1) for all the analyzed samples. The detection limit of the proposed method was calculated as 5 ng g(-1) of sample utilizing 5 minutes of electrodeposition (+300 mV vs. Ag/AgCl) on the gold electrode. (c) 2006 Elsevier Ltd. All rights reserved.

Food resources partitioning among sciaenid fishes (Perciformes, Sciaenidae) of the Flamengo bay, Ubatuba, southeastern Brazil

The determination of the diet and feeding habits is one of the principal aspects of the study on fish biology, as feeding is a basic process and its study is necessary for the understanding of the populations' dynamic and ecology. The Sciaenidae family has a significant occurrence in the bay's demersal ichthyofauna, constituting an important fishing resource. The goal of this work was to analyze how the partitioning of available food resources takes place among the ten sciaenid species which live in the Flamengo Bay. One single survey, consisting of three trawls, was carried out with a fishing boat equipped with two otter-trawl. Diet analysis showed that all species are exclusively carnivore, using several items as food, but crustaceans are the main food ingested. The use of the ''Proportional Overlap Index'' showed possible overlapping between six couples of species but in the majority of cases, morphologic differences between these species, such as the mouth position, probably determine different foraging strategies.

Plastic debris collars on juvenile carcharhinid sharks (Rhizoprionodon lalandii) in southwest Atlantic

Three juvenile Brazilian sharpnose sharks (Rhizoprionodon lalandii) caught in gillnets in southeast Brazil, southwest Atlantic, were found with plastic debris rings around their gill or mouth region. The rings caused severe abrasion on the sharks' tissues as the animal grew, the collars probably hampering normal feeding and/or ventilation since two of the collared individuals were emaciated. The rings were identified as detachable lid parts from plastic bottles, likely thrown overboard by fishery and/or recreation boats. As several carcharhinid shark species dwells and reproduce in shallow waters, the impact of discarded plastic debris likely is greater on this shark type. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Tracking the fin trade: Genetic stock identification in western Atlantic scalloped hammerhead sharks Sphyrna lewini

Location or stock-specific landing data are necessary to improve management of shark stocks, especially those imperiled by overexploitation as a result of the international shark fin trade. In the current absence of catch monitoring directly at extraction sites, genetic stock identification of fins collected from major market supply chain endpoints offers an overlooked but potentially useful approach for tracing the fins back to their geographical, or stock of, origin. To demonstrate the feasibility of this approach, we used mitochondrial control region (mtCR) sequences to trace the broad geographical origin of 62 Hong Kong market-derived Sphyrna lewini fins. Of these fins 21% were derived from the western Atlantic, where this species is listed as 'Endangered' by the International Union for the Conservation of Nature (IUCN). We also show that S. lewini mtCR sequences are geographically segregated in the western Atlantic (overall ΦST = 0.74, n = 177 sharks), indicating that breeding females either remain close to, or home back to, their natal region for parturition. Mixed stock analysis simulations showed that it is possible to estimate the relative contributions of these mitochondrial stocks to fin mixtures in globally sourced trade hubs. These findings underscore the feasibility of using genetic stock identification to source market-derived shark fins to obtain essential and otherwise unavailable data on exploitation levels, and thus to productively inform stock assessment and management of S. lewini and potentially also of other fished shark species. © Inter-Research 2009.

Captura incidental de um tubarão-baleia, Rhincodon typus (Orectolobiformes, Rhincodontidae), na costa do Ceará, Nordeste do Brasil

A whale shark, Rhincodon typus, was incidentally captured off Ceará on January 2009, during gillnet fishery. This is the second occurrence record for this species off the State and the first including material deposited in a scientific collection.

Feeding habits of Guiana dolphins, Sotalia guianensis, from south-eastern Brazil: New items and a knowledge review

This study presents new information on feeding habits of Guiana dolphins, Sotalia guianensis, in south-eastern Brazil, together with new regression equations to evaluate the weight and length of fish from otoliths, showing an overview on the knowledge about this species-diet in this area. Eighteen stomach contents had been analysed and compared to 180 samples collected in another eight feeding studies. The analysed specimens were either incidentally caught in gillnets used in coastal waters by the fleet based in the Cananéia main harbour (25°00âS 47°55âW), south of São Paulo State, or found dead in inner waters of the Cananéia estuary between 2003 and 2009. Based on the index of relative importance analysis, the most important fish species were the banded croaker, Paralonchurus brasiliensis. Doryteuthis plei was the most representative cephalopod species. Stellifer rastrifer was the most important fish species observed in dolphins in inner estuarine waters and P. brasiliensis in recovered dolphins from coastal waters. Loliguncula brevis is the only cephalopod species reported from dolphins found in inner estuarine waters up to date. Doryteuthis plei was the most important cephalopod species observed in coastal dolphins. When considering other feeding studies, the most representative fish family in the diet of S. guianensis was Sciaenidae, which is mainly represented by demersal fishes. The main preys of S. guianensis are abundant in the studied areas, which may indicate an opportunistic feeding habit. The majority of them are not the most important target species by the commercial fishery in south-eastern Brazil. © 2012 Marine Biological Association of the United Kingdom.

Indução à reprodução e desenvolvimento embrionário e larval do ciclídeo acará-açu Astronotus ocellatus (Agassiz, 1831)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise genética do tubarão-raposa Alopias superciliosus no Oceano Atlântico, utilizando região controle do DNA mitocondrial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Filogeografia do tubarão mako Isurus oxyrinchus utilizando marcadores moleculares do DNA mitocondrial

Pós-graduação em Ciências Biológicas (Genética) - IBB

Caracterização da estrutura genética populacional do tubarão-crocodilo (Pseudocarcharias kamoharai) no Atlântico equatorial utilizando marcadores moleculares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de marcadores genéticos para identificação de espécies de tubarões comercializados no Brasil

Pós-graduação em Ciências Biológicas (Zoologia) - IBB