I didn’t know the full extent of salmon farming problems and you, too, might be under the misconception that farmed salmon is a good idea to protect wild salmon stocks. It is and it isn’t. In Norway, the number of wild salmon has halved since the ’80s to half a million. In Norway there are 849 million farmed salmon kept in crowded open-water pens from which 200,000 escape annually.
The escaped farmed salmon mate with wild salmon which spreads sea lice and disrupts spawning grounds. This has caused a catastrophic decline in wild salmon stocks.
And so, the objective is to keep farmed salmon completely separate from wild salmon which is not the case today.
A Norwegian business has pioneered a closed-tank system which is 72 m deep and which holds 200,000 fish. It’s so big that it would be the highest building on the west side of Norway if it was above ground.
The salmon in this tank can’t get out and see lice also can’t get in. The tank circulates seawater and filters out salmon waste. This is a contributor to rising nitrogen levels in Norway’s fjords.
It also passes the waste into a separate tank where it is used to create biogas for power generation.
It’s a step in the right direction but there is a massive uphill struggle to rectify the problems and damage to wild stocks caused by salmon farming.
And the Norwegian aquaculture lobby is resisting the switch because they say that closed pens have not been sufficiently tested.
Comment: I suspect that they resist this change because it would cost too much to build these tanks and it would damage their profit margins. It seems they don’t mind damaging wild salmon stocks as long as they can make enough money out of farmed salmon.
If that is true, this is a typical clash between big business and wildlife conservation. Big business is nearly always rides roughshod over conservation if conservation gets in the way of profit margins. And that argument applies on a massive scale including climate change.
The report comes from The Times of Thursday, October 17, 2024. Thank you for the report. The Norwegian company which built the tank is Eide Fjordbruk and the chief executive is Sondre Eide. The original report as I understand it comes from NPR the American broadcaster.
MORE: England’s salmon stocks at lowest on record. Infographic.
Here is some more detail on the damage caused by farmed salmon to wild salmon:
Farmed salmon can pose several risks to wild salmon populations. Here are some of the main ways farmed salmon can harm wild salmon:
1. Spread of Disease and Parasites
Farmed salmon are often raised in open-net pens, which are typically placed in coastal waters near wild salmon habitats. These pens allow diseases and parasites, such as sea lice, to transfer easily between farmed and wild salmon. Sea lice, in particular, can infest juvenile wild salmon, weakening them and decreasing their survival rates.
2. Escapes and Genetic Pollution
Farmed salmon can escape from pens due to storms, predators, or structural failures. When these farmed salmon mix with wild populations, they can interbreed, leading to genetic dilution. Wild salmon are well-adapted to their local environments, and interbreeding with farmed salmon (which often come from different genetic stocks) can reduce the fitness of wild populations, making them less resilient to environmental challenges.
3. Competition for Resources
Escaped farmed salmon can compete with wild salmon for food and habitat. This competition can be especially damaging in areas where wild salmon populations are already stressed by other environmental factors, such as climate change or overfishing.
4. Pollution and Environmental Impact
Fish farms can generate significant amounts of waste, including uneaten food, feces, and chemicals used to treat diseases and parasites. This waste can degrade the quality of nearby water, harming wild salmon and other marine species. Additionally, fish farms can contribute to nutrient overload in coastal waters, leading to harmful algal blooms that further degrade the habitat.
5. Predation
Farmed salmon attract predators such as seals and sea lions. When these predators are drawn to fish farms, they can inadvertently prey on nearby wild salmon as well, adding to the pressure on wild stocks.
For these reasons, the relationship between farmed and wild salmon has raised environmental concerns, particularly in regions like British Columbia, Norway, and Scotland, where both industries coexist.
