RESUMO

Mercury (Hg) is a toxic globally spread pollutant that has been found at increasing concentrations in the South Atlantic Ocean. The present work provides the first insight into the total mercury (HgT, unfiltered waters) content in the water of the Brazilian Exclusive Economic Zone (BEEZ), within a 24°S to 20°S. Water samples were collected from surface to 3400 m depth along transects, and analyzed with atomic fluorescence. The mean HgT concentration for the Tropical Water mass (TW) was 6.3 ± 1.4 pM (n = 16), for the South Atlantic Central Water (SACW), 5.9 ± 0.7 pM (n = 8), for the Antarctic Intermediate Water (AAIW), 5.0 ± 0.6 pM (n = 2), for the Upper Circumpolar Deep Water (UCDW), 6.5 pM (n = 1), and for the North Atlantic Deep Water (NADW), 5.7 ± 0.9 pM (n = 12). HgT concentrations were highest throughout the BEEZ in comparison with other parts of the Atlantic Ocean, farther from the coast.

Assuntos

RESUMO

The predation of cookie-cutter sharks Isistius spp. upon the early life stages of yellowfin tuna Thunnus albacares, skipjack tuna Katsuwonus pelamis and little tunny Euthynnus alletteratus are described. New evidence suggesting a connection between commercial fishing and predation by Isistius sp. is presented, with these sharks biting tunas hooked in surface waters during daylight. The healing patterns of the wounds made by the sharks are described in detail and, although such damage is known to negatively influence market price elsewhere, it is not the case on the south-east Brazilian coast.

Assuntos

RESUMO

We report the distribution of selected lipid biomarkers specifically sterols and aliphatic hydrocarbons in sediment cores from Cabo Frio, SW Atlantic continental shelf, Brazil, corresponding approximately to the last 700 years. In the Cabo Frio region, a costal upwelling occurs as a quasi-seasonal phenomenon characterized by nutrient-rich bottom waters that intrude on the continental shelf and promote relatively high biological productivity compared to other Brazilian continental shelf areas. The results for sterols indicate the predominance of organic matter (OM) inputs related to marine organisms, mainly plankton, in all of the cores along the time scale studied. Principal component analyses show three different groups of variables, which may be associated with (i) the more effective intrusion of the nutrient-rich South Atlantic Central Water, resulting in the increase of marine lipid biomarkers such as sterols and short-chain n-alkanes; (ii) the influence of the Coastal Water with higher surface water temperature and subsequently lower primary productivity; and (iii) OM characterized by high total organic carbon and long-chain n-alkanes related to an allochthonous source. Relatively high concentrations of sterols and n-alkanes between 1450 and 1700 AD, chronologically associated with the Little Ice Age, suggest a period associated with changes in the local input of specific sources of these compounds. The concentrations of lipid biomarkers vary over core depth, but this does not suggest a notably high or low intensity of upwelling processes. It is possible that the climatic and sea surface temperature changes reported in previous studies did not affect the input of the sedimentary lipid biomarkers analyzed here.

Assuntos

RESUMO

Were described the fishing activity practiced in Cabo Frio, eastern coast of Rio de Janeiro State, and its interaction with cetaceans by the fishermens perception, and was checked if traditional management actions are developed to minimize the possible negative interactions between fisheries and these animals. From July to November 2012, 45 ethnographic interviews were conducted with local fishermen. The fishermen are male, aged predominantly between 34 to 51 years old, and with low formal education level. Line types (hand line and long line) were preferably used as fishing artifacts and the main products were teleost fish (demersal and pelagic). All fishermen interviewed reported the occurrence of cetaceans in the region. Whales are sighted mainly in the summer time, when their presence is related to food availability according to fishermen, and in winter and spring time due the migratory movements that include this region as a route. Dolphins occur throughout the year and their presence is related to food availability. All reports of interactions between cetaceans and fisheries were classified as negative. Interactions withfishing artifacts and boats collision were mentioned only by 24% (n = 11) and 4% (n = 2) of the interviewed to whales and dolphins, respectively. Despite the high overlap between fishing areas and animals occurrence, there was not verify traditional management actions considering the cetaceans. This reflects the low negative interaction between fishing activity and these animals in the region.

Foram descritas a atividade de pesca artesanal praticada no município de Cabo Frio, costa leste do Rio de Janeiro, e as interações com os cetáceos na região a partir da percepção dos pescadores, verificando-se a existência de manejo tradicional para minimizar as possíveis interações negativas entre a pesca e esses animais. Entre julho e novembro de 2012 foram realizadas 45 entrevistas etnográficas com pescadores que atuam na região. Os pescadores eram do sexo masculino, com idade predominante entre 34 e 51 anos e baixa escolaridade formal. As modalidades de linha (linha-de-mão e espinhel) foram os petrechos preferencialmente utilizados e os principais produtos capturados foram peixes ósseos (demersais e pelágicos). Todos os entrevistados relataram a ocorrência de cetáceos na região. Avistagens de baleias ocorreram principalmente no verão, segundo os pescadores, devido à disponibilidade de alimento, e no inverno e na primavera, a partir de movimentos migratórios que incluem a região como rota. Os golfinhos ocorreram ao longo do ano todo e sua presença foi relacionada à disponibilidade de alimento.Todos os relatos de interações entre cetáceos e a pesca foram classificados como negativos. Interações dos animais competrechos de pesca e colisões com embarcações foram indicadas por 24% (n = 11) e 4% (n = 2) dos entrevistados para baleias e golfinhos, respectivamente. Apesar da elevada sobreposição entre as áreas de pesca e de ocorrência dos animais, não se verificou a existência de um sistema de manejo tradicional da pesca considerando os cetáceos. Isso reflete a baixa interação negativa entre a pesca eos animais na região.

Assuntos

RESUMO

Were described the fishing activity practiced in Cabo Frio, eastern coast of Rio de Janeiro State, and its interaction with cetaceans by the fishermens perception, and was checked if traditional management actions are developed to minimize the possible negative interactions between fisheries and these animals. From July to November 2012, 45 ethnographic interviews were conducted with local fishermen. The fishermen are male, aged predominantly between 34 to 51 years old, and with low formal education level. Line types (hand line and long line) were preferably used as fishing artifacts and the main products were teleost fish (demersal and pelagic). All fishermen interviewed reported the occurrence of cetaceans in the region. Whales are sighted mainly in the summer time, when their presence is related to food availability according to fishermen, and in winter and spring time due the migratory movements that include this region as a route. Dolphins occur throughout the year and their presence is related to food availability. All reports of interactions between cetaceans and fisheries were classified as negative. Interactions withfishing artifacts and boats collision were mentioned only by 24% (n = 11) and 4% (n = 2) of the interviewed to whales and dolphins, respectively. Despite the high overlap between fishing areas and animals occurrence, there was not verify traditional management actions considering the cetaceans. This reflects the low negative interaction between fishing activity and these animals in the region.(AU)

Foram descritas a atividade de pesca artesanal praticada no município de Cabo Frio, costa leste do Rio de Janeiro, e as interações com os cetáceos na região a partir da percepção dos pescadores, verificando-se a existência de manejo tradicional para minimizar as possíveis interações negativas entre a pesca e esses animais. Entre julho e novembro de 2012 foram realizadas 45 entrevistas etnográficas com pescadores que atuam na região. Os pescadores eram do sexo masculino, com idade predominante entre 34 e 51 anos e baixa escolaridade formal. As modalidades de linha (linha-de-mão e espinhel) foram os petrechos preferencialmente utilizados e os principais produtos capturados foram peixes ósseos (demersais e pelágicos). Todos os entrevistados relataram a ocorrência de cetáceos na região. Avistagens de baleias ocorreram principalmente no verão, segundo os pescadores, devido à disponibilidade de alimento, e no inverno e na primavera, a partir de movimentos migratórios que incluem a região como rota. Os golfinhos ocorreram ao longo do ano todo e sua presença foi relacionada à disponibilidade de alimento.Todos os relatos de interações entre cetáceos e a pesca foram classificados como negativos. Interações dos animais competrechos de pesca e colisões com embarcações foram indicadas por 24% (n = 11) e 4% (n = 2) dos entrevistados para baleias e golfinhos, respectivamente. Apesar da elevada sobreposição entre as áreas de pesca e de ocorrência dos animais, não se verificou a existência de um sistema de manejo tradicional da pesca considerando os cetáceos. Isso reflete a baixa interação negativa entre a pesca eos animais na região.(AU)

Assuntos