Omega-3s: Which Fish Are Highest?

November 22, 2011 By Matt Straw

This is Pike Mike Harrison, our guide up on the Tree River last August, filleting an Arctic char. "These fish have the richest omega-3 concentrations known," he says. Hmmm.

Omega-3 fatty acids improve heart health, brain function, and brain health while protecting joints and connective tissue. Studies show omega-3s aid in healthy development of infants. The American Heart Association recently upgraded their guidelines on supplements for women, recommending a substantial increase in the dosage of omega-3s.

According to Self Nutrition Data.com, flaxseeds and flaxseed oil maintain the highest omega-3 content. Ranked right behind them was the "salmon." But which of the dozens of species are they referring to?

While writing for the March/April issue of In-Fisherman, I ran across claims that spring kings, or "springers" have the highest omega-3 content of all the salmon. Intuitively, that makes sense. Springers run sooner and stay in rivers longer than summer- or fall-run kings, living off stores of fat and oil for months. And, as it turns out, the highest levels of omega-3s so far known to exist in salmon are found in the early kings that run the Yukon River in Alaska, according to researchers there. Some of those fish journey over 1000 miles to ancestral spawning habitat. They may not eat a thing for six months. That's a long roll between snacks, so nature provides them with a dense dose of fatty acids. Best batteries in the known universe? Hmmm.

Going down the list we find things not readily available in the supermarket. At least, not in the stores around here. (Maybe in Kugluktuk.) Right behind Chinook salmon we find a fish called agutuk — native to Alaska. Right behind that is the oil in the skin of the bearded seal, followed by menhaden oil. So what about other species of fish we can find in the store or in the wild around here? I looked up Arctic char on All-Fish Seafood Recipes.com and found out char have 1.41 grams of omega-3s in every 3.5 ounces of fillet. That's pretty high. Right up there with spring kings. Pike Mike might be onto something. People hawking salmon-oil products claim the redness of flesh is an indicator of omega-3 content, and if so, one would think the sockeye should be highest among salmon. One website claims there are 1.2 grams of omega-3s in every 3.5-ounce serving of sockeye.

Well, Arctic char flesh is plenty red, too. Almost fluorescent red. But the same website claims that omega-3s are highest in kings, then silvers (coho), then sockeyes. Hmmm. On many websites claiming to know something about omega-3s, we continually find reference to the figure 1.2 grams per 3.5 ounces of "salmon." Again — which species? Purdue University lists lake trout at the top of a list of over 50 species. But not just any lake trout. At the top of the omega-3 chain is the siskowet, a fatty strain of laker found only in the depths of Lake Superior (though some now claim they persist in the depths of Great Bear and a few other lakes in the Northwest Territories). They spawn about 150 feet down in Superior, and that's the shallowest they rise during the open-water season. I spent 3 days chasing siskowet on Lake Superior with friends Tim Barefoot and Matt Wilder recently. We caught them working vertically with 5-ounce jigs on their spawning flats in August. Those critters were so encased in fat they could burn a grill to the ground. Ugh. Maybe if you boiled them first? We just fizzed them (had to, amazingly enough) according to instructions from some USGS biologists we met on Isle Royale who were studying them at the time. And we let 'em go, deciding discretion was the better part of culinary valor in their case.

Speaking of which, spring kings are often called "royals" because of their exquisite flavor. Hmmm. So much for the fishy-taste theory. Digging further and further in, I found conflicting data everywhere. The internet can be a woefully inadequate medium sometimes, but at least most sites list the same fish, including mackerel, cod, sardines, burbot, herring, shad, Atlantic salmon, whitefish, halibut, caviar, brook trout, carp, and many others. In varying order. Interesting to note that some sources say the highest omega-3 content is found in the skin or in the flesh right next to the skin — like vitamins in fruit — suggesting we steak them out (as shown) for the broiler or grill to obtain the highest benefit. Some fish, like sockeyes, have a fairly equal distribution of omega-3s throughout the flesh. Hmmm. Recently holed up in our Steelhead Cave, I cleaned a couple onchorynchus mykiss, otherwise known as rainbow trout. Well, in this case steelhead, but the designation onchorynchus indicating the Pacific salmon clan. According to Nutrition Data.com, steelhead have 307 mg of omega-3 oils per ounce — right up there with most other salmon.

I tend to run my fillet knife about an eighth of an inch above the skin because the flesh next to the skin has the strongest "fishy taste" in my opinion. But is that taste an indicator of omega-3 content? The gray flesh around the lateral line and next to the skin, along with the belly flesh, also holds the most contaminants — like mercury. Hmmm.

Everything's a compromise. But the bottom line: Fish is fantastically good for you no matter what kind of propaganda the tofu eaters at PeTA are spewing these days. Cod-liver oil is said to have more than twice the omega-3 content of any salmon per ounce — right up there with flaxseed oil. There's that fishy taste again. I much prefer a salmon fillet simmered in red curry with coconut milk — something else we've whipped up outside the old Cave. Who says life has to be dull just because you're staying in a cheap motel?