Observations on the levels of total mercury (Hg) and selenium (Se) in species common to the artisanal fisheries of Seychelles.

Exposure to mercury (Hg) in Seychelles is expected to be high owing to the large amounts of fish regularly consumed. In spite of this consumption, a recent long-term study of child development found no evidence that higher prenatal exposure to Hg increases the risk of neurological disorders. To identify the major sources of mercury in the diets of Seychellois fish consumers, 16 species of fish common to local markets were tested for total Hg. Selenium (Se), which may act as an antidote to Hg toxicity, was also measured. Mercury and selenium were measured using standardised laboratory procedures. The average total Hg concentration across all species was 0.07mg/kg while the Se concentrations averaged 0.29mg/kg. Based on the pooled species dataset, there was no correlation between total Hg and Se concentrations, suggesting that joint bioaccumulation of these elements does not occur in the reef fishes tested. Barracuda (Sphyraena jello) had the highest concentration of Hg (0.36mg/kg), a level that was below European Union guidelines. Although Seychellois traditionally eat a large amount of fish, barracuda would need to be consumed more than 5 times a week for FAO/WHO Total Hg Provisional Tolerable Weekly Intake (PTWI) limits to be exceeded, an unusual rate of consumption. Further investigations are needed to assess the risks posed to the population through the consumption of marine fish and fish products.

The fishing sector in Seychelles: an overview, with an emphasis on artisanal fisheries.

Seychelles has a well-developed fishing sector that is a vital part of the social and economic development of the country. Three main types of fisheries are recognised: artisanal fisheries targeting demersal and semi-pelagic species, semi-industrial fisheries targeting pelagic species, and industrial fisheries targeting species of tuna. In economic terms, the industrial fisheries are of greatest importance. The per capita consumption of fish in Seychelles is one of the highest in the world and the artisanal fisheries contribute significantly to the protein requirements of the country. Artisanal fisheries catches have remained fairly stable since comprehensive monitoring began in 1985, averaging 4568 MT per annum. A wide range of fish and invertebrate species are targeted and the general catch composition has remained stable. Landing of tuna by the purse seine fleets has grown substantially over the last 18 years, attaining a record catch of approximately 42 945 MT in 2002. The demersal stocks targeted by the artisanal fisheries are known to be over- or optimally exploited close to centres of population, and lightly exploited elsewhere, whilst the industrialised fisheries for pelagic species require a precautionary approach to management as some stocks are being exploited close to maximum sustainable yield levels. Future development in Seychelles is tightly linked to fisheries and the marine environment in general.