Marine debris ingestion by coastal dolphins: what drives differences between sympatric species?

This study compared marine debris ingestion of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in a sympatric area in Atlantic Ocean. Among the 89 stomach contents samples of P. blainvillei, 14 (15.7%) contained marine debris. For S. guianensis, 77 stomach contents samples were analyzed and only one of which (1.30%) contained marine debris. The debris recovered was plastic material: nylon yarns and flexible plastics. Differences in feeding habits between the coastal dolphins were found to drive their differences regarding marine debris ingestion. The feeding activity of P. blainvillei is mainly near the sea bottom, which increases its chances of ingesting debris deposited on the seabed. In contrast, S. guianensis has a near-surface feeding habit. In the study area, the seabed is the main zone of accumulation of debris, and species with some degree of association with the sea bottom may be local bioindicators of marine debris pollution.

Helminths of the marine tucuxi, Sotalia fluviatilis ( Gervais, 1853 ) ( Cetacea: Delphinidae ), in northern Rio de Janeiro State, Brazil

Os objetivos deste trabalho foram reportar os helmintos parasitas do tucuxi marinho, Sotalia fluviatilis, na costa norte do Estado do Rio de Janeiro; e checar se a taxa de infestação varia com as características do hospedeiro (sexo e maturidade) e estações do ano. Entre 1989 e 2002, 80 tucuxis marinhos capturados acidentalmente em pescarias foram examinados e quatro espécies de parasitas foram registradas: Braunina cordiformis, Anisakis typica, Halocercus brasiliensis e Nasitrema sp. O parasitismo no tucuxi marinho corrobora seu hábito alimentar e não foram constatadas diferenças nas taxas de infestação entre machos e fêmaes, jovens e adultos, assim como entre as estações do ano. Este trabalho reporta pela primeira vez a ocorrência do gênero Nasitrema no tucuxi marinho.

Bone lesions in Sotalia fluviatilis (Cetacea) as a consequence of entanglement: Case report

The objective of the present study was to describe a set of lesions caused by entanglement of Sotalia fluviatilis accidentally captured by gillnet on July, 23, 1995, in the Northern Rio de Janeiro State (21º37'S-041º01'W), Southeastern of Brazil. The specimen presented lacerated lesions of the skin and subcutaneous tissue around the posterior extremity of the rostrum. Nylon twines were found associated to these lesions. Bone and teeth lesions were also observed in the underlying area and affected the maxillaries, pre-maxillaries and mandibles. The lesions were likely caused by non-lethal entanglement in fishing gears. Abnormalities in the growth layer pattern of the damaged teeth between the third and sixth growth layers suggest that this encounter had taken place when the specimen was around three years old. The data indicate that non-lethal encounters with fishing gears may cause serious health problems to small cetaceans and reduce their lifetime. This is the first description of fisheries-related chronic lesions in S. fluviatilis

Fishing activity in Northern Rio de Janeiro State (Brazil) and its relation with small cetaceans

Research on fishing activity at Atafona village, in Northern Rio de Janeiro, Brazil (21°35'S), was carried out between 1987-96 for the purpose of relating it to the accidental capture of small cetaceans and of estimating the relationship between fishing activity and the diet of small cetaceans. Data on fishing operations were obtained at the cold storage plants management, from interviews with fishermen and personal observations. The most representative fishing resources were Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus,and Rhizoprionodon porosus. Gillnets are responsible for the accidental capture of small cetaceans in the region, mainly Pontoporia blainvillei and Sotalia fluviatilis (marine form). Four types of gillnets that are used on the region ("minjuada", "sarda", "caçoá" and "pescadinha") were dangerous to these species because they are placed in their preferred habitat. There is no competition between fishermen and small cetaceans due to the selection in the capture of commercialized fishes.

Investigação sobre a atividade pesqueira na localidade de Atafona, Norte do Rio de Janeiro, Brasil (21º25`S), foi conduzida entre 1987-96 com o objetivo de relacioná-la com a captura acidental e a dieta dos pequenos cetáceos. Dados sobre as operações pesqueiras foram obtidos na administração dos entrepostos de pesca, através de entrevistas com pescadores e observações pessoais. Os recursos pesqueiros mais representativos foram Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus, and Rhizoprionodon porosus. As redes de espera são responsáveis pela captura acidental de pequenos cetáceos na região, principalmente de Pontoporia blainvillei e Sotalia fluviatilis (forma marinha). Quatro tipos de redes de espera que são usadas na região ("minjuada", "sarda", "caçoá" and "pescadinha") foram mais perigosas para essas espécies pois são colocadas no seu hábitat preferencial. Não existe competição entre pescadores e pequenos cetáceos devido à seleção na captura dos peixes comercializados.