Editor's note: October is National Seafood Month, and to celebrate, we’ll be featuring a series of blog posts about seafood, sustainable fishing and health. Today we’re taking on mercury.
Maybe when you think of mercury you think of old thermometers. But did you know that mercury in seafood can affect your health?
As a result of antiquated manufacturing techniques, a few chlorine factories release mercury pollution into nearby rivers and streams, which ends up in the ocean, where it travels up the food chain, becoming more and more concentrated in larger and larger fish, including favorites such as tuna and swordfish.
What’s the danger of mercury in fish? Mercury is a neurotoxin and can cause symptoms such as headaches, foggy thinking, muscle stiffness, dizziness, nausea, and hair loss. Mercury is dangerous for women who are or may become pregnant because children are particularly susceptible to the effects of mercury poisoning.
The best way to protect yourself and your family is to learn what kinds of seafood have high mercury levels and to consume these only in moderation. The Monterey Bay Aquarium’s Seafood Watch guide contains information about mercury levels as well as about sustainability.
We’ve made progress over the years, both in requiring stores to provide information about mercury and in getting companies to switch to less dangerous ways of producing chlorine. However, mercury in fish remains an issue. Just this summer, Oceana was instrumental in convincing the Spanish government to release a study finding that more than half of mako shark and swordfish samples had dangerous levels of mercury.
You can learn more about mercury and you can also take action by asking Walmart and Sam’s Club to post safety notifications about mercury in fish.
Spain’s biggest newspaper, El País, featured Oceana prominently in this morning’s cover story. The article describes Oceana’s unrelenting effort to make previously confidential research regarding unsafe mercury levels in large fish freely accessible to the public, highlighting an important victory with implications for the health of the Spanish populace and the transparency of the Spanish government.
Here’s the back story: in 2003, Spain’s Spanish Institute of Oceanography (IEO) conducted a large research study that documented levels of mercury and other heavy metals in large fish such as various sharks, swordfish, and bluefin tuna.
The results of the study were not good: 62.5 percent of the 128 mako shark samples and 54.2 percent of the swordfish samples contained high, unpermitted levels of mercury. Despite this alarming evidence, the results were never released due to concerns about its possible impact on the fishing industry.