Health Risk Assessment of Globally Consumed Shark-Derived Products

Abstract

Shark meat and fin soup are seafood commodities exported and consumed worldwide. Because sharks are large and slow-growing marine predators they tend to accumulate a large amount of mercury in the form of methylmercury. Due to this well-documented biomagnification, many nations have blanket advisories urging citizens, especially pregnant women and children, to avoid consuming shark-derived products. Mercury levels, however, may vary greatly within and among shark species. Since shark-derived products can represent an important source of protein in some communities, assessing the consumption health risks of different shark species is needed. Here, we analyzed total mercury, methylmercury and selenium concentrations of 267 processed fin trimmings from Hong Kong Special Administrative Region and mainland China and 33 meat samples from Trinidad and Tobago. In conjunction with the most recent data from consumer practices surveys, and taking into account consumption rates, average body weight of consumers and the chemical interaction between mercury and selenium, we calculated the risks of consuming shark meat and shark fin soup from different shark species. We found that blanket maximum safe consumption limits applied to shark products are often overly restrictive because they do not take mode of consumption into account. Nonetheless, meat and fin products from large hammerhead species, Sphyrna mokarran, S. zygaena and S. lewini, need to be avoided by consumers, and not sold by retailers, due to high mercury levels. Species-specific advisories should also be issued for meat and fin products from oceanic whitetip and dusky smooth-hound sharks, which should be avoided by women of childbearing age.