Wednesday, June 10, 2009

Sustainable Fish

The oceans are in trouble. Fisheries are collapsing. Many fish populations, once so plentiful, are now nearly gone. I am concerned about this both as a scientist in marine conservation and as a cook. I had a teacher in college whose research seemed to indicate that all tuna, everywhere in the world, were endangered species. And yet I couldn't imagine cutting tuna out of my diet. It's a really overwhelming thought.

I wish I had the time and energy right now to write a whole essay on the problem of sustainable fishing and eating, but it's just too big of a topic. Here are some salient points to ponder:

Modern fishing practices, including huge trawl nets that catch everything within a certain area, have drastically increased the number of fish caught by commercial fisheries. Our technology has gotten ahead of the ocean's ability to heal. (Incidentally, global warming also leads to ocean acidification which can dissovle coral reefs. Don't even get me started on the number of fish we might lose that way; it's a whole different topic.)

In general, big fish have longer lives, reproduce later in life, and have fewer offspring. Because of this, their populations take longer to recover from low population numbers due to fishing. Small fish, like anchovies and sardines, are more resilient and can bounce back from overfishing more quickly. Even so, these populations can be overfished to extinction: Monterey's collapsed sardine industry on Cannery Row is a great example.

Most farmed fishing is environmentally disastrous. Think of it as the ocean equivalent of cage-raised chickens, where disease is rampant and the animals don't have any semblance of a normal life pattern. The difference is that in aquaculture, net pens of farmed fish are surrounded by wild fish populations. The net pens leech antibiotics and animal waste into the surrounding waters, creating an anoxic "dead zone" under the pens in which no fish can survive. To make matters worse, net pens occasionally rip or malfunction and let farmed fish out into the wild population. They are so pumped up on antibiotics that they live while the wild fish get sick and die. If they interbreed with the wild gene pool, they can severely affect the genetic diversity and the population's ability to survive in the wild. That said, some fish, such as tilapia, can be net-raised more or less safely and on a vegetarian diet.

According to Mark Bittman of the New York Times, almost 90% of the world's fish oil harvested each year goes into fish food. It takes three pounds of wild fish to feed one pound of farmed salmon. That just seems like a bad idea, all around.

The tides are turning on popular opionions of fish and sustainability. The upscale Japanese restaurant Nobu in New York has been the subject of much bad press and recent protests due to offering bluefin tuna on their menu. A new film in the U.K. called "The End of the Line" has a lot of people talking about these issues. As people begin to understand more about the land-based farming system and factory foods, this awareness is spreading to ocean-based foods as well.

Monterey Bay Aquarium's Seafood Watch program has made a lot of the questions surrounding good fish/bad fish easier for consumers. Their lists are tailored to different parts of the country (and even sushi menus) with the categories avoid, good alternatives, and best choice. Even so, a single type of fish could fall into multiple categories depending on where and how it was caught. Most people working at a normal grocery store fish counter won't have enough information to definitively place a particular fish in one category. Worse, they could be lying to you or the fishermen could be lying to them--there is a huge amount of mislabeld fish in the markets. (My marine forensics lab deals with improper labeling all the time; it's rather common.) All this makes things very difficult for the consumer to make informed seafood choices.

So what can you do when you want to buy fish? Buy as close to the source of your seafood as possible, using the Seafood Watch list as a guide. A fish market is generally better than your local grocery store, although Whole Foods has taken some steps towards only selling sustainably. Talk to the fishermen themselves whenever possible--ask where they fish, how they catch their fish, what other species they catch accidentally (this is called bycatch). My local farmers' market has a few different fish vendors, but then again I'm in the seafood heaven of Seattle. The important thing is to find a knowledgeable person you trust, and then buy the majority of your seafood from the "best choices" category. Consumers really do have power to change fishing and eating habits! Buy responsibly, stay educated, spread the word, and hopefully we'll be able to eat fish for a long time yet.

Photos by Flickr users sharkbait, Secret Seasons, and GoBot.

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