Freshwater wildlife face an uncertain future

January 23, 2019 by Andrea Jane Reid And Steven J Cooke, The Conversation

Pacific salmon are one of Canada's iconic creatures. Each summer, they complete their, on average, four- to five-year-long life cycle by returning from their rich ocean feeding grounds to the creeks and streams where they were born. Here, following in the "footsteps" of their parents, they will lay eggs, die and give rise to the next generation of salmon.

This transit from freshwater to the sea and back again is sometimes thousands of kilometres long. It can also be treacherous—the fish must navigate steep river rapids and avoid voracious predators.

But the trek is only being made harder by unnatural challenges. Humans continue to dam and pollute rivers, overfish and introduce invasive plants and animals. And this is just the tip of the iceberg in terms of how humans are profoundly reshaping fresh waters in Canada and around the world.

For our research on the migration and conservation of Pacific salmon, we have looked at how freshwater ecosystems—lakes, rivers, streams and wetlands—are changing around the globe. Society has its finger on the pulse of the oceans, but what about our too often forgotten fresh waters?

Lakes and rivers in crisis

While fresh waters make up just a fraction (0.01 per cent) of all the water on the planet, they are home to nearly 10 per cent of the Earth's known animal species, including one third of all vertebrates (anything with a backbone). There are even more species of fish in freshwater ecosystems than there are in the ocean.

This picture is, sadly, changing quickly. The World Wide Fund for Nature (WWF) recently published the "Living Planet Report 2018," showing that freshwater species loss is more severe than species declines on land or in the ocean.

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