The days now grow shorter, and with the change of season, the salmon begin to transform too. In the Adams River, one of the largest remaining wild sockeye runs on the planet, heads for home.

As they get ready to spawn, their colour changes from silver to bright red and green, signalling to potential mates that they are the same species.

Salmon stop eating once they return to freshwater. Swimming upstream to their spawning grounds, they will rely only on the body fat they’ve stockpiled for this very reason. Against the current, they swim hundreds of kilometres, often overcoming elevation increases as high as 600 metres or higher.

Returning salmon will often face the uphill battle – literally – of a waterfall or a hydroelectric dam

Fish ladders are sometimes built to help them over obstructions. A series of cascading pools, the fish ladders still require the salmon to leap upwards from one pool to the next to overcome the hurdle.

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While fighting the current on this part of their journey – and sometimes each other – salmon also face a whole new set of predators.

The odds are stacked against salmon at every stage of their lives. Select from the tiles below to see some of the hazards they face, and how many salmon will make it through to the next stage in their journey.


The salmon that make it this far have accomplished a round trip lasting thousands of kilometers through salt and freshwater, overcoming obstacles and avoiding perils on every leg of their journey.


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