With the recent opening of Whole Foods Market with its extensive seafood display and Kanaloa Seafood in the Oxbow Market, seafood lovers in Napa Valley face tempting choices of fish and other marine creatures. Combined with the existing offerings from other markets such as Sunshine, Browns Valley,  Vallerga’s and Osprey, we now have choices we never had before.

Unfortunately, all those options can be intimidating. Everyone knows that fish with its Omega-3 oils and low levels of bad fats is good for you — except that some is contaminated with mercury, PCBs and other toxic materials.

Likewise, the recent collapse of salmon fishing in California reminds us that we’re running out of some species, like local salmon and the so-called Chilean sea bass, more prosaically known as Patagonian toothfish.

Environmentalists and the government warn us to avoid or reduce consumption of many fish, yet many stores continue to sell these and other aquatic creatures that are either possibly unhealthful, endangered or raised or caught under questionable circumstances.

    

How do you choose fish?

What’s a consumer to do? How do you know what fish to eat and which to avoid?

One prime source of information is the Monterey Bay Aquarium, which has devoted a great deal of attention to this subject. Its Web site, www.seafoodwatch.org, gives detailed suggestions. It also offers a wallet-size fold-out card for guidance when you buy seafood or eat out.

Unfortunately, the situation is also complex.

Americans are most fond of tuna, salmon and  shrimp, but according to the Aquarium, some of each is undesirable, while other varieties and sources are fine.

You might think, for example, that farming fish would be better than catching wild species, but that isn’t always true. Where and how the fish is caught can be vital, too.

The good news

But let’s start with the good news:

Just like the commercials say, Alaska wild salmon is about as tasty as anything we eat and it’s a great choice.

Not so farmed salmon, mostly Atlantic. It is raised in pens in the ocean and fish escape, eating native species and spreading disease to wild fish while interbreeding with them. The farms pollute coastal waters, and raising a pound of salmon requires three pounds of small fish for food.

Neither wild nor farmed salmon contains high levels of mercury, however.

Good choices are Pacific cod caught on long lines, Pacific halibut, Alaska wild pollock, California and Oregon black rockfish, Alaska and British Columbia black cod or sablefish and white sea bass.

Small fish like sardines and anchovies, as well as squid, are fine. They’re abundant and don’t contain much mercury.

Also, American (and Canadian) farm-raised mollusks — clams, mussels, oysters, bay scallops and abalone — are great, too. We have strict rules that ensure they’re raised without damaging the environment and are healthy.

Likewise, US-raised finfish are safe and sustainable choices, notably freshwater-raised trout, tilapia, catfish, and ocean barramundi, a tasty new choice, as well as farmed striped bass and sturgeon (and caviar) from other places.

Dungeness crab is good, and they cut off crabbing if stocks are low.

Shrimp are chancy. Pink Oregon shrimp are good, as are spot prawns from British Columbia, and American farmed or wild shrimp and spot prawns are OK.

Imported farmed wild shrimp are bad, either because they’re farmed in a very damaging way to the environment, or the wasteful way they’re caught. That includes the cheap shrimp served in most low-end restaurants and sold at local markets.

U.S. farmed crayfish are good, too, but not imports.

U.S. or British Columbia trolled or pole-caught albacore and skipjack are fine, and trolled bigeye and canned light, white or albacore tuna is OK (though the latter contains  mercury).

    

Avoid these

The news about what fish you should definitely avoid is large and discouraging, and contains some very popular choices.

The government and many health authorities say we should not eat some fish at all, especially large, slow-growing open ocean fish because they eat small fish and concentrate mercury in their flesh.

These include Chilean sea bass, orange roughy, redfish and red snapper, sharks, wild sturgeon, swordfish, all bluefin tuna, and albacore, bigeye and yellowfin tuna caught on long lines. They are all both endangered and tainted with mercury.

These recommendations aren’t universal, however.

Don Disraeli is the founder of Kanaloa Seafood, and his outlet in the Oxbow Market prominently displays the origins of seafood while it attempts to focus on sustainable and healthful fish. Since 1983, Disraeli, who has a doctorate in biology, and his wife, Randee, a former researcher at Scripps Institute of Oceanography, have searched the world for premium seafood and tried to cultivate enlightened seafood suppliers.

Kanaloa is the only seafood company in North America certified to ISO 14001, which identifies companies that better manage the impact of their activities on the environment and demonstrate sound environmental management standards.

Disraeli thinks the warnings about mercury are excessive. “This whole mercury thing is really overblown. Unless you eat these fish all the time, it’s probably not something you should worry about.”

He noted, “Seafood is so good for you that no matter what fish you eat, it’s better for you than not eating fish.”

Nevertheless, many experts agree while it might not be a big concern for adults who eat fish occasionally, it may be a concern for children or pregnant women.

More to the point, many of these fish are illegally caught or overfished as well.

That beautiful maguro and toro at the sushi bar may come from some of the most endangered large fish in the sea. Fortunately, other acceptable tuna like some albacore and skipjack are tasty, too.

Some people are trying to farm tuna in open-ocean pens, but it takes about 25 pounds of small fish to produce one pound of tuna.

Other popular fish to avoid because of overfishing or killing of other species as byproducts include Atlantic cod, imported king crab, spiny lobster, grouper, monkfish,  imported mahi mahi/dorado/dolphinfish, trawled rockfish, mid-Atlantic sea scallops and imported shrimp.

Disraeli warned, however, “We couldn’t stay in business if we followed the Aquarium’s guidelines completely.”

Okay, but...

Some other seafood are basically okay, but there are some concerns about how they are fished or farmed.  

One problem is identifying the source of the fish, or even the real variety, since fish are sold under many fanciful names.

Kanaloa Seafood market in the Oxbow Market clearly identifies all its fish by origin, and offers sustainable choices, though it doesn’t claim that all its fish meet the strictest standards — it is working on that, but might not have much to sell otherwise.

Although ahi tuna is sometimes proscribed, for example, Disraeli gets his from the Marshall Islands after careful research there.

As you look over the seafood menus and shopping lists — and price fish in enlightened markets — it’s obvious that the days of eating our favorite cheap fish with abandon are over.

Just like everything else — oil, water, clean air — seafood isn’t unlimited.

Choose carefully and treasure your choices.