This is for those of you who struggle with the complex world of sustainable seafood.
The Good FISH rule:
F: farmed fish: is not all bad (closed-containment, land-based fish farms are far superior to ocean based farms, such as how salmon is farmed. An exception to this would be farmed shellfish (clams, oysters, mussels) which is an excellent choice because no antibiotics are added to the water, no wild fish food is needed to feed them and they filter feed, cleaning the oceans. Many farmed fish (trout, arctic char, catfish, tilapia, barrimundi) don't require a lot of wild fish food to be taken from the oceans to feed them, unlike farmed salmon. If you want to make a bigger impact with your buying power, refuse to eat farmed salmon.
I: investigate: ask questions at your restaurants and fish counters and support good corporate decision making and chefs and fishmongers doing the right thing: PCC, Safeway (really!), Target and Whole Foods lead the pack in supporting sustainable seafood. Costco was ranked 14th worst according to Greenpeace. You have more power than you think you have - it's contained in your questions and your wallet - use them.
S: smaller: eat less fish, 1/4 pound per person per meal of finfish is plenty - simply put, there are too many people who are demanding to eat too much fish, we need to give the oceans a break and besides, we're supposed to eat more vegetables anyway; eat fish lower on the food chain (they are literally smaller - think sardines, mackerel, anchovies) to reduce your mercury exposure and preserve the ocean's ecological balance.
H: home: if you live in America, eat seafood from US waters or farmed here - we have better laws and environmental standards when compared to fish caught/grown elsewhere.
Check out Casson Trenor's 4S rule to help you with navigating sustainable sushi buying decisions and a big tip of the keyboard to him for inspiring me to come up with my own version of sustainable seafood rules.