Salmon cannon to help fish past landslide

Plans are underway for a pneumatic fish pump, also known as a salmon cannon, to be used to help fish migrate past a landslide on British Columbia’s Fraser River.

The landslide was discovered in the remote canyon north of Lillooet last June. Huge pieces of rock from a 125-metre cliff had sheared off and crashed into the river, creating a five-metre waterfall.

The salmon cannon, on lease from the Seattle-based company Whooshh Innovations, will help move the fish past the pinch point in the river.

From the fish’s perspective it’s a completely smooth ride and it actually feels to them like they’re in the water. And that’s why when they come out the exit they just swim away. They swim in, they slide, they glide, and they swim off. There’s no shock to their system.

Vince Bryan III, CEO of Whooshh Innovations and inventor of the Salmon Canon (purposely spelled with only one “n” to distinguish the eco-friendly invention from a murderous weapon)

If for some reason it can’t be used, salmon would be transported upstream as tens of thousands were last year by truck and helicopter.

While the COVID-19 pandemic has not significantly delayed work at the site of the landslide, it has affected scientists’ ability to track how many salmon are heading out of fresh water and into the ocean this spring.

10 facts about wild salmon…

  1. Salmon love both salt and freshwater

Salmon are considered anadromous which means they live in both fresh and salt water. They are born in freshwater where they spend a few months to a few years (depending on the species) before moving out to the ocean. When it’s time to spawn, they head back to freshwater.

Close up of a Sockeye salmon running the rapids when returning to spawn
© Andrew S. Wright / WWF-Canada

Very few other fish can survive in such wide ranges of salinity, and would die if they moved between salt and fresh water the way that salmon do. That’s because when saltwater fish are exposed to freshwater, it can cause their cells to burst. And when freshwater fish are exposed to salt water, it can cause their cells to shrivel, due to a process known as osmoregulation. Luckily salmon have some pretty amazing physiological and behavioural adaptations that allow them to survive in both environments.

2. After living for many years at sea, return to the river in which they were born to spawn

There are many theories about how they are able to do this. Some state that salmon use the Earth’s magnetic field to guide them, while others say they use their strong sense of smell to guide them home. Habitat changes and losses can affect the salmon’s ability to return to their native spawning river, posing a threat to the survival of future salmon generations.

3. Salmon have a really strong sense of smell

Atlantic salmon can smell one drop of scent in an area the equivalent of ten Olympic size pools!

Sockeye salmon © Scandinavian Fishing Yearbook / WWF

4. Salmon change colour!

Salmon can be three different colours over the course of their life. For example, check out the picture above: juvenile sockeye salmon are light coloured and spotted, and during their adult years in the ocean, they are silvery blue. When it’s time to spawn, the adult bodies turn a brilliant red and their heads turn green.

5. Salmon are considered keystone species

This means they have a disproportionately large impact on their ecosystem relative to how many of them there are. If a keystone species were to disappear, their ecosystems would change significantly. Rotting salmon carcasses transfer valuable nutrients from the ocean to the land. Scientists have traced nutrients from salmon bodies and found them in mosses, herbs, shrubs, trees, insects, song birds, bears and wolves!

Atlantic salmon swimming upriver to spawn, Canada.
© Paul Nicklen/National Geographic Stock / WWF-Canada

6. Salmon are facing multiple threats

The wild Atlantic salmon is in decline across Scotland. Their unique lifestyle – spawning in rivers and migrating thousands of miles downstream, across the North Atlantic and back again – means they face a huge range of pressures during their life span, from water pollution and fishing bycatch to physical barriers.

7. Salmon are named after their runs

Many believe that the word “salmon” comes from the Latin word salmo or salire, which means “to leap”. If you’ve ever seen salmon battling rapids and strong currents as they head upriver to spawn, then you know they are aptly named.

8. Salmon around the world

Salmon in the United States are found mainly on the Northwestern coastline as well as all around Alaska. There is a small amount on the Atlantic coast and there are some in the Great Lakes as well. There are schemes in Canada to support dwindling wild populations.

9. What do salmon eat?

Young salmon feed on plankton. As they get older, they feed on other things such as insects, small invertebrates, small fish, and other sea organisms.

Spawning is usually the last act of a salmon before it dies

10. Reproduction

Because of the effort and energy it took for the salmon to travel back upstream, they will die shortly after they spawn. The embryos will hatch and then will eat their own yolk. When the yolk is gone, they begin searching for other food. They are now known as “fries.” Soon, the fries will be ready to head out to the saltwater where they will spend most of their adult life until they travel back the place they hatched to spawn.

How can I help wild salmon..?

Eat them

Buy wild salmon at the supermarket. Farmed salmon is cheaper (thus making up 70% of the market) but is also more likely than wild-caught to contain contaminants, like carcinogenic dioxins and PCBs.

Farmed salmon is not sustainable and may harm the environment by spreading disease to wild-caught fish and encouraging overfishing for their feed.

Salmon farms are infested. Shutterstock

Farmed salmon are fed pellets made out of fish oil and smaller fish, ground-up chicken feathers, poultry litter (guano) genetically modified yeast, soybeans and chicken fat.

Wild salmon gets its distinctive pink flesh from a substance called astaxanthin, a pigment found in shrimp-like krill that the salmon eat.

Dead farmed salmon at bottom of fish farm net

Farmed fish are often fed a synthetic version of astaxanthin, without which they would be grey or off-white in colour. These ‘pigmenting supplements’ are the most expensive component of the farmed salmon diet, constituting up to 20% of feed costs.

Farmed salmon with lice damage, filmed in a fish farm in Loch Roag
CORIN SMITH

Wild caught salmon has a healthier ratio of anti-inflammatory omega-3 fats to inflammatory omega-6 fats, as well as an overall better nutritional profile.

Sockeye salmon swimming upstream in annual migration
© Garth Lenz / WWF-Canada

What else can I do..?

Storm drains go right into our rivers, lakes, and seas. Never dump liquids with chemicals down storm drains.

Compost instead of buying fertiliser for your garden, this helps keeps chemicals out of our rivers and oceans.

Close up of a Sockeye salmon (Oncorhynchus nerka) caught in the rapids
© Andrew S. Wright / WWF-Canada

Plant native plants. Native plants are better adapted to the environment so
they need less water and do not need fertiliser or pesticides. This saves water and keeps the rivers healthier.

Be careful what you flush down your toilet or sink, only flush biodegradable products.

Avoid chemicals. Anything you flush or drain makes its way to our streams, rivers and oceans.

JEFF J MITCHELL

Use low-flow toilets and showers, or stick a brick or jug of water in the back of your toilet to make it use less water. This can save ½ gallon of water per flush, which leaves more water for salmon!

Share what you know! Tell your neighbours, friends, and parents what you’ve learned and teach them how they can help salmon too!

SOURCE 1, SOURCE 2, SOURCE 3, SOURCE 4, SOURCE 5, SOURCE 6, SOURCE 7, SOURCE 8, SOURCE 9, SOURCE 10, SOURCE 11, SOURCE 12, SOURCE 13

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