Bluefin tuna contains mercury; the Food and Drug Administration plans to amend regulations to tighten limits, while the Fisheries Agency worries that fishermen's rights and interests will be harmed.
Bluefin tuna is delicious, but it carries a hidden concern over residual heavy metal mercury. Last year the Food and Drug Administration, Ministry of Health and Welfare (abbreviated as FDA) floated a plan to revise the standard for methylmercury in fishery products, lowering it from 2ppm to 1ppm; but the Fisheries Agency held that the standard was too strict and could deal a severe blow to the domestic fishing industry.
Kao Yi-ting, section chief of food safety in the FDA's Food Division, said the standard expected to be lowered last September referenced the limit value of 1ppm for methylmercury set in the regulations of the United States and the Codex Alimentarius Commission (Codex); Australia and the European Union instead set total mercury content at no more than 1ppm; Japan has no regulation for large or deep-sea fish such as tuna, swordfish and sharks, though in the Ministry of Health, Labour and Welfare's advice for pregnant women the allowable value is only 0.3ppm.
Today Greenpeace released the results of its own tests on the mercury content of bluefin tuna sashimi sold on the market, among which one sample of bluefin tuna belly sashimi from Donggang, Taiwan, China, had a methylmercury (Methyl Merury) content of 1.14ppm, which, while meeting the current 2ppm standard set in the FDA's Sanitary Standards for Fishery Products, would be a concern for exceeding the limit if it were lowered to 1ppm in the future.
Yen Ning, ocean project director at Greenpeace, said bluefin tuna has been listed as an endangered species by the International Union for Conservation of Nature (IUCN), and people should no longer eat endangered fish just to follow a trend; for the sake of sustainable use of the oceans and food safety alike, people should stop eating bluefin tuna as soon as possible.
Bluefin tuna is a large migratory fish at the top of the food chain, so it readily accumulates heavy metals in its body; mercury is converted by microbial action into the more toxic methylmercury, which can be absorbed by the human body through the gastrointestinal tract; once methylmercury is present in a pregnant woman's body, it can even affect an infant through breastfeeding, hindering the infant's neurological development and, in severe cases, causing permanent damage to the brain, memory, emotions, vision, hearing and kidney function.
Fisheries Agency: Bluefin tuna is not a farmed fish and its pollution sources cannot be controlled; overly strict law revision would affect fishermen's livelihoods
The Fisheries Agency explained that heavy metal accumulation in large fish comes from the food chain, unlike the controllable pollution of human aquaculture, and that if the law were tightened, the proportion of non-compliant samples would increase, in turn hitting the livelihoods of more than 3,000 fishing households in the country.
Kao Yi-ting explained that because bluefin tuna is scarce and of high economic value, destroying it outright once it exceeds the limit would be quite wasteful. Therefore, the FDA will currently coordinate with the Fisheries Agency and move toward an approach of "reasonable production and marketing control, diverse protein intake, and not recommending it for special groups (such as pregnant women and children)."
In addition, Greenpeace also said that vendors do not label the place of origin of bluefin tuna clearly, and only reveal the source of the product after being asked; as far as she knows, after catching its fish Japan marks the catch before it enters the market, so it is possible to know clearly which fishing boat the catch came from, where it was caught and when it was caught.
In response, Huang Hung-yen, deputy director-general of the Fisheries Agency under the Council of Agriculture, said that it will currently study the labeling of the place of origin of fishery products from the fishing boat catch to the market. However, because bluefin tuna catches are controlled internationally, the Fisheries Agency controls how much bluefin tuna is caught each year, by which fishing boats and at which locations.
At the same time, to disclose more information, the Fisheries Agency said it invited relevant vendors to a meeting today to establish a "simple traceability system," meaning that in the future it will announce information such as the names of fishing boats licensed to catch bluefin tuna in each ocean area and the fish species caught, so that restaurant operators can post it and win consumers' trust.
Does the mercury standard need to be lowered? Expert: a risk assessment should be done
Lee Chun-chang, a professor at the Institute of Environmental and Occupational Health at National Cheng Kung University, said that although the heavy metal content in bluefin tuna caught in the Indian, Atlantic and Pacific Oceans may differ, habits and body size are also reasons affecting the level of heavy metal concentration, so at this stage labeling the place of origin is meaningless.
On whether the allowable level of methylmercury should be lowered to 1ppm, he said a risk assessment must be conducted based on people's food intake before deciding.
Yen Tsung-hai, a physician in the Toxicology Division at Linkou Chang Gung Memorial Hospital, said that from a physician's standpoint, the stricter the food safety standard the better; but any standard-setting needs to take multiple opinions into account, so he hopes the Ministry of Health and Welfare and the Fisheries Agency will strike a balance between public food safety and the fishery industry.