In nature and on our farms, salmon are being selected for different reasons
Survival in nature is never guaranteed, and it’s hard work. Even a single cell has to go through billions of steps before it can successfully copy itself and continue the survival of its species. It took about four billion years for this reproduction process to develop, and it’s still not perfect – random variations happen regularly.
Selected by nature
While variations can be harmful, resulting in problems such as cancer or genetic defects, they can also be helpful, giving creatures an edge in nature’s survival race. In fact, if the reproduction process was too good, we wouldn’t have the massive diversity of life on earth that we have today, which comes from helpful variations over time.
Wild Pacific salmon have taken advantage of helpful variations over the past several million years to survive floods, wildfires, volcanoes, and even the Ice Age. Their main strategy is to reproduce through sheer numbers. A single female sockeye salmon can lay as many as 5,000 eggs. Only about 1 in 1,000 eggs will result in a fish that survives its lifecycle to return and spawn, but that’s still a net gain and ensures the best and strongest survive to grow the next generation.
Variations in wild salmon
Because of the sheer number of salmon in the sea, it’s not hard to find some with harmful variations. From 1958-1962, researchers sampled 20,000 sockeye, pink, and chum salmon and found 3% of all the fish had some kind of spinal abnormality. Other abnormalities are commonly seen in wild fish, which can be caused by water temperatures during their freshwater growth phase, or injuries and conditions at sea.
Selected by humans
While wild salmon are naturally selected to survive the harsh realities of nature, farmed salmon are selected by humans for things that make them better-suited for farming. These include traits such as quicker growth, delayed maturity, efficient food digestion, and size.
Just like in nature, there can be harmful variations in farmed salmon, leading to fish with abnormalities. But unlike in nature, more of these fish may survive in a protected farm environment. They are usually removed at the hatchery before we enter our salmon into the ocean, but some may develop abnormalities after some time at sea.
Some manage to find a survival strategy, staying near the surface and corners of the pen where they can eat feed dust and bits of pellets the other fish miss. Some may not adapt well to the ocean environment, and become very skinny. Fish that are not likely to survive are commonly removed by our farmers as soon as they see them.
Thanks to the care and attention of our farmers, the vast majority – more than 95% – of our salmon grow to be healthy, full-sized and beautiful-looking fish.