Credit: Alexandra Morton

Wild salmon is less nutritious because it burns up all its good fats and oils on its long journey to spawn. That’s the claim by professors at Stirling University in Scotland who studied declines in omega-3 levels in farmed salmon due to increased use of plant based feeds.  It brought a quick reaction from one Alaska expert.

I laughed. It’s a silly remark.

Scott Smiley of Kodiak is a retired professor and noted expert in cell and developmental biology. He says farmed salmon, like other living creatures, are what they eat.

 You can adjust farmed fish so that their diets have much more omega 3 and they are able to consume that and store the omega 3s that way. So they can have more, it’s just a question of cost. It’s relatively expensive to do.  

Catching wild fish to feed farmed fish has fallen out of favor and that’s forced fish farmers to find feeds sourced from plants or synthetics. The Scottish report said that in 2006, 80 per cent of the average salmon’s diet was made up of oily fish; now it is just 20 per cent. Smiley says most farmers now balance feeds with fish meals at critical times in the fishes’ development.

You know the same thing happens with humans. You don’t rice or beans alone, you eat them together and that’s because there certain nutritional requirements that aren’t available in either rice or beans, but together they are there.  

One million smoked salmon meals are eaten in the UK every week, according to the report, and salmon purchases there have increased 550 percent. But even with the lower omega levels, farmed is still better for you than wild the researchers concluded.

It’s hard to tell which fish have the highest amount of omega 3 oils because levels vary by local populations.

So herring off of Kodiak may have very high levels of o3, but herring from some other place may have half of that. So there is variation in natural populations that is really intense.  And it totally depends on what they eat.

Alaska could ramp up production of fish parts that provide high levels of various nutrients. But the current budget crunch likely precludes investment.

So I think it’s going to take awhile before the capability to produce new products that are more exciting in the world of dietary feed formulations for fish.  

Meanwhile, the claim that wild salmon burn up all their fats and oils in their travels home brought a final rebuff –

I did contact a friend who is a fish nutritionist and my friend asked if the Scottish researcher was a professor of medieval literature.  

The farmed salmon   report is in the journal Scientific Reports.