July 15, 2020

Nutritional differences between salmon species explored in study

Is farmed salmon really not so nutritious as the wild-caught fish, as some people believe?

Not really, says Dr. Stefanie Colombo, an assistant professor of Aquaculture at Dalhousie University in Canada, who explored the nutritional differences between salmon. With her research, which was published recently in the Journal of Agriculture and Food Research, she hopes to dispel misunderstandings about farmed salmon, the university's Dal News reports.

"I was surprised by a few things. It's really the species of salmon that makes the biggest difference in nutritional quality—not whether it was farm raised or wild caught, or whether it's certified organic or environmentally certified", she said in the report.

"For example, there was a big difference in the wild salmon we looked at—between Sockeye, Chinook and Pacific. The results did clearly show that salmon types are different", she added.

The study involved comparing the nutritional information for six different types of salmon that were purchased and are commonly available to Canadians, focusing particularly on the omega-3s. They were also analysed for mercury. The fish included farmed Atlantic, farmed organic Atlantic, farmed organic Chinook, wild Chinook, wild Pacific pink and wild Sockeye.

The different salmon species that Colombo tested were either wild, farmed, organic, non-organic, environmental certified and non-environmental certified.

According to Dal News, Dr. Colombo found that the more expensive wild Sockeye, which can be bought at C$31.50 per pound, and wild Chinook had the most nutrient-dense and highest omega-3 content. But she also discovered that farmed Atlantic salmon, which costs much cheaper at about $12.50/lb, had the lowest mercury content and had also a high nutrient density.

The study says that Sockeye and Chinook can be consumed less frequently for the same nutritional value, as they are expensive and have limits on sustainable catch levels. For those who enjoy eating salmon more frequently, farmed Atlantic is a great option for its nutritional value, cost, availability and low mercury, according to Colombo.

The volume of farmed Atlantic salmon has increased by 800% since 1990, while 72% of salmon eaten today are farm-raised, Colombo's study has found.

Dr. Stefanie Colombo (Image: Dal News)