What Is The Difference Between Farmed & Wild Salmon?

Salmon that you see sold in supermarkets across the world generally falls into one of two basic categories: farmed or wild. Wild salmon are those that developed and were caught directly in the wild, in nature, whereas farmed salmon are raised on a farm just like other farm animals, only they are raised in water. There are other differences between the two salmons, namely in species, consumption levels and their respective levels of contamination.

Species

One of the central difference between farmed and wild salmon is they are different species of salmon. Most wild salmon caught are one of five Pacific salmon species. These are Chum, Pink, Coho, Chinook and Sockeye. They're caught between June and September, but their numbers are generally limited. Farmed salmon, on the other hand, can be eaten year-round. They are generally Atlantic salmon (and sometimes Coho). In other words, this difference between wild and farmed salmon is they are actually different fish.

Consumption

Because they are farmed year-round and, therefore, more readily available than wild salmon that can only be consistently caught between June and September most years, farmed salmon is consumed more than wild salmon. However, that wasn't always the case. Only since 1998 has most of the consumed salmon been farmed. Still, farmed salmon has made the consumption of salmon cheaper and more consistent; the past quarter century has seen a 40-fold increase of the annual global production of farmed salmon.

Differences in Contaminant Levels

A 2004 study by researchers at the University of Albany concluded that farmed salmon contained higher levels of contaminants than wild salmon. The researchers concluded this is because of the two fish's differing diets: while the wild salmon feed on aquatic organisms, farmed salmon eat what the farm feeds them. This is often not natural, wild aquatic animals, but rather an almost synthetic feed that is high in fat and consists of fishmeal of fish oil to promote quicker growth. It is the contaminants in these feeds that give farmed fish higher levels of contaminant. Additionally, the study found that farmed salmon sold in New Orleans, Denver, Los Angeles, Washington, D.C., Seattle, Chicago, New York and Vancouver had lower levels of contamination than farmed salmon sold in Boston, San Francisco and Toronto.

Health Risks

Because of their contaminant levels, there are some potentially significant health risks in eating certain amounts of farmed fish. For one, while you can eat four to eight meals with 8 oz. of wild salmon per month, EPA cancer risk parameters recommend eating no more than one meal with 8 oz. of farmed salmon per month.