Presença de dinoflagelados bentônicos potencialmente tóxicos: identificação do perigo em áreas destinadas à maricultura na Baía de Sepetiba, RJ. / Presence of potentially toxic benthic dinoflagellates: identification of hazard in shellfish growing areas in the Sepetiba Bay, RJ.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The malacoculture (cultivation of shellfish) is the second most significant activity of the Brazilian mariculture, where the cultivation of bivalve molluscs (mussels, oysters and scallops) stands out nationally. The bivalves show an excellent nutritional value when they are used as food by humans, containing a great biological value of protein, low in fat, vitamins, minerals and carbohydrates. However, their contamination by toxic algae and its phycotoxins represents a danger to consumers health, particularly in the production areas without monitoring, considered by the Intergovernmental Oceanographic Commission of high risk to public health. The effective monitoring is the only way to ensure the hygienic-sanitary quality of commercialized shellfish and consumers safety. The diarrheic phycotoxin okadaic acid (OA) was detected in mussels from natural beds and from shellfish farms located in the bays of Sepetiba and Ilha Grande (RJ). Its production was associated with planktonic dinoflagellates of the Dinophysis genus. However, the role of benthic dinoflagellates in the production of OA and other benthic phycotoxins is still poorly studied. In this context, this study aimed to investigate the occurrence of potentially toxic benthic dinoflagellates associated with macroalgae collected in Guaiba and Marambaia islands, areas of cultivation and extraction of mussels (Perna perna). Macroalgae were collected monthly (january to december 2008) by snorkeling (1 meter), using a polyethylene bag, then were transferred to polyethylene bottles and agitated (1 minute) to separate the epiphytic dinoflagellates. The material was filtered on differents meshes (150, 115 and 20 μm) and the final volume of 250ml was concentrated and set. Only the potentially toxic and harmful dinoflagellates were identified and quantified (Method of Uthermöl) under inverted microscope. The macroalgae were fixed and identified. The cell density of dinoflagellates was expressed on the dry weight of macroalgae (células.g-1). Were identified 32 species of macroalgae (8 Phaeophytes, 6 chlorophytes and 18 rhodophytes). From 97 samples of dinoflagellates was identified 11 morphotypes of dinoflagellates: Coolia sp., Prorocentrum cf. arenarium, P. cf. balticum, P. cf. concavum, P. cf. emarginatum, P. gracilis, P. cf. lima, P. cf. mexicanum, P. micans, Ostreopsis sp1 and sp2 occurring in Padina, Sargassum, Codium, Caulerpa and Laurence, substrates frequently during the study period. The analysis of variance bifactorial showed differences between spatial and temporal concentrations of Ostreopsis and Prorocentrum. Ostreopsis occurred throughout the year on both sites associated mainly with Padina gymnospora. The Guaiba island constantly showed higher cell densities and richness of Prorocentrum. Summer was the season of year when Prorocentrum was more abundant. Coolia showed punctual and sporadic occurrence. The knowledge of the occurrence of potentially toxic dinoflagellates is important to better understand the real implications of these species in the production and transference of toxins in coastal trophic web, and can help generating information to the development of mariculture in the southern coast of Rio de Janeiro from the perspective of safe food.

ASSUNTO(S)

alimento seguro. tecnologia de alimentos ficotoxinas mussels safe food. mexilhões phycotoxins

ACESSO AO ARTIGO

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