I love fish. I love swimming with them and I love eating them. I know this is kind of sick, but a trip to the aquarium will always put me in the mood for a nice piece of salmon. But wait, is it Atlantic salmon that’s a protected species? Is farmed OK? What about wild Alaskan salmon? Herein lies the problem. You can’t just go ordering fish off the menu all willy-nilly and a trip to the fish counter at your local grocery store is likely to make your head spin.

I worry about overfishing, pollution, and the threat that global warming is having on various species and fish habitats in oceans and streams all over the world. I could just not eat fish, but it’s so healthy and so delicious! And since I have been trying to eat less meat, fish has been starring in a lot more of my meals lately.

So instead of giving up fish, I have decided to educate myself. I’ve been reading about what kinds of fish to avoid, but how they are raised (farmed or wild–I guess if they’re wild they aren’t really being raised, but you get the idea) and how they are caught (line-caught or trapped and dragged) are also important considerations. Not to mention the contaminants–many fish contain mercury and polychlorinated biohenyls (PCBs) that are potentially harmful, especially if you are pregnant. Luckily I found a helpful list of rules to follow in Green Chic: Saving the Earth in Style by Christie Matheson and I’d like to share it with you.

• If you want salmon, opt for wild Pacific or Alaskan salmon. Farmed salmon tens to be high in pollutants and sadly low in flavor; wild Atlantic salmon is a protected species.

• Wild salmon, sardines, squid, Arctic char, and Atlantic fluke are the lowest-mercury fish. Avoid other fishes such as sea bass, swordfish, Atlantic halibut and tuna–particularly if you are expecting. Don’t panic if you have a bite accidentally, but don’t order it every week as an entree either.

• Avoid farmed shrimp, especially imported farmed shrimp, which is associated with high levels of pollutants that damage wild fish populations and degradation of mangrove forests. Also avoid shrimp caught by net-dragging (for every pound of shrimp caught, there are up to 15 pounds of bycatch, or other sea creatures such as sea turtles, killed.)

• Think of fish more like you think of produce and eat it only when it’s in season near you. For example, mackerel swims up the eastern seaboard and passes by Boston in late May or so. That’s a darn good time to eat mackerel in Boston, and it’s the only time sustainability-minded Boston chefs will have it on the menu.

• Ask questions! Find out where your fish came from, if it’s being harvested sustainably, what levels of mercury and PCBs it contains, and how it was caught. If they don’t know, say “no thank you!”

Now I know this is a lot to take in, and a lot to remember. The best tip I think I’ve heard is to carry a seafood information card, like the Monterey Bay Aquarium Seafood Watch provides pocket size downloadable Seafood Watch Pocket Guides–these are regional and up to date and allow you to select fish from your part of the country.

And for more information, read Safe, Sustainable Fish: Easy Greening by my colleague Melissa Breyer who is much more of an expert than I am.

The bottom line is that fish is really good for you, and if you love it then there’s no reason not to eat it. With a little information and perhaps a cheat sheet in your back pocket, you can check your green guilt at the door of the fish market.