Minamata disease was first discovered in Minamata city in Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation‘s chemical factory, which continued from 1932 to 1968. This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay and the Shiranui Sea, which, when eaten by the local populace, resulted in mercury poisoning. While cat, dog, pig, and human deaths continued for 36 years, the government and company did little to prevent the pollution. The animal effects were severe enough in cats that they came to be named as having “dancing cat fever”.
As of March 2001, 2,265 victims had been officially recognised as having Minamata disease (1,784 of whom had died) and over 10,000 had received financial compensation from Chisso. By 2004, Chisso Corporation had paid $86 million in compensation, and in the same year was ordered to clean up its contamination. On March 29, 2010, a settlement was reached to compensate as-yet uncertified victims.
A lot of cats love fish, but feeding it as more than a very occasional treat could is not a good idea and could be harmful to your cat’s health. The primary fish used in cat food are salmon, tilefish (usually identifed as ocean whitefish on the label) and tuna. Each of them presents health issues, because fish can contain toxic doses of common water pollutants, heavy metals, and other contaminants. Mercury is considered one of the top ten chemicals of major public health concern by the World Health Organization.
Mercury in fish
Mercury ends up in the air from power plant emissions. When it rains, the mercury in the air falls into lakes, rivers and oceans. Bacteria in these bodies of water convert the mercury into methylmercury, a highly toxic form that gets easily absorbed into small organisms. Small fish ingest it when they eat those tiny organisms, and bigger fish eat the smaller fish. Because of this, larger fish, who are at the top of the predatory food chain, contain higher levels of mercury.
We should be constantly examining what we are feeding our cats. The oceans are getting more polluted, certainly not less polluted, and the fish coming out and processed is done in such quantities that I am sure contaminated fish is in many cans How many cats are showing signs? Who knows. But I fear the tip of the iceberg will soon be exposed. Love your cat, beware of the food you are feeding them.