For once in my life, I'm happy to have an allergy

Since the start of the Industrial Revolution, the people of our civilization have transformed the world like no other species can. We have knocked down forests to build cities and plant food. We have dammed rivers to make power. And we have detrimentally changed the composition of the air we breathe and the water we drink. In the process, we have made numerous species extinct, as well as some cultures, and continue to threaten the survival of countless more. But while we do our damnedest to wipe out every last species on earth (including ourselves), our polluting ways may actually end up saving the lives of some marine life that many of us, although not me, find very tasty.

Last week, The Madison Declaration on Mercury Pollution was published in the Swedish journal Ambio. The Declaration was put together by many of the world's leading scientists who study mercury and they concluded that methylmercury levels in many fish are high enough that a worldwide warning that people eat less fish should be issued. The scientists state that we have three times as much mercury "falling from the sky today than before the Industrial Revolution" (source) resulting in the contamination of our waterways and the fish that live in them, especially the larger predator fish (fish that eat other fish) like shark and tuna. The warning is especially for young children and expectant mothers, as mercury can do some nasty things to developing childen, namely fetuses. The U.S. Environmental Protection Agency warns:

[m]ethylmercury exposure in the womb, which can result from a mother's consumption of fish and shellfish that contain methylmercury, can adversely affect a baby's growing brain and nervous system. Impacts on cognitive thinking, memory, attention, language, and fine motor and visual spatial skills have been seen in children exposed to methylmercury in the womb (source).

We are seeing such elevated mercury levels in our oceans primarily because it is emitted by coal fired power plants (source). While most industrial countries now limit the amount of mercury these plants can emit, developing industrial nations don't, off-setting the cuts that we have managed to make. Mercury pollution also comes from old gold mines as well as from the flooding that occurs when rivers are dammed. My uncle, a biologist who studies fish species, wrote me the following:

One other point to consider; mercury occurs naturally in soil. But when that soil is flooded, it can be methylated and released into the water column where it is amplified through the food chain and may persist for decades in fish and their predators. That's exactly what happens every time a river is dammed and a reservoir created.

So what is the result of all this? Well first off, I am sure that people will eat less fish, especially shark, swordfish and tuna. Some will just stop all together and add it to the list of growing things that are "bad for us." Others will keep on eating it, but increasingly turn to the less vulnerable species like salmon (because, you know, there is an endless amount of salmon in the water). And while we humans may suffer because fish is so good for us (although not me, it kills me), the fish, in the end, may actually benefit from us making them inedible. As my Uncle explains:

When considering toxic contamination, there is one point that is often forgotten. As an example, the human population has never been so big, human life expectancy so long but, at the same time, so contaminated by all kinds of gross toxins. Contamination may have specific nasty effects, but living organisms are quite capable of dealing with toxins at sub-lethal levels. Humans have been doing so for centuries. So fish populations will persist and may even increase but they will be less healthy than uncontaminated populations (just like the human example). Actually one bonus fish reap from being contaminated is that eating mercury-contaminated fish is so dangerous for human health that human populations generally stop exploiting contaminated fish populations. Its a trade-off, increased contamination levels lead to decreased exploitation rates. The fish kind of win in a way. It reminds me of an old Star Trek episode where the crew visits a beautiful planet where life forms flourish but nothing can be eaten by humans because everything is poisonous.

So there we go - humanity, increasing the mercury in every fishes body, making them unsafe for us to eat and ultimatley, saving them from extinction. If only the Atlantic Cod had been so lucky.

Cross-posted at Dodosville.