Migratory Fish Are Disappearing
21 May 2024This post comes to PBS Nature from World Wildlife Fund (WWF). WWF and Nature are collaborating on a series of blog posts from WWF conservation scientists that will share the stories and motivations behind cutting-edge conservation research.

©Jeremy Shelton
Have you thought there might be fewer butterflies fluttering around your garden this spring? You’re not wrong. Eastern migratory monarch butterflies have been making headlines this year because their populations have decreased by 59% in 2024 alone. But there is another major group of migratory species facing striking declines that are rarely in the news—freshwater fish.
Freshwater fish, particularly those that migrate through oceans, rivers, and streams, are often overlooked in conservation initiatives despite their vital roles in providing food and livelihoods to millions of people and as valuable species in and of themselves. Nowhere is the world’s biodiversity crisis more acute than in freshwater ecosystems. Around 35% of wetlands have been lost in the past 50 years and only 1/3 of the world’s large rivers are still free flowing. Overall, monitored freshwater animal populations have declined by an average of 83% since 1970, more than any other species on land or sea. The 2024 Living Planet Index (LPI) update for migratory freshwater fish signals an 81% average decline in migratory freshwater fish populations over the last 5 decades, a 3.3% loss every year. This dramatic drop sounds an urgent alarm for conservation efforts to protect these crucial species and preserve freshwater ecosystems. It is not just about protecting nature; it is essential for human survival too.

©Petteri Hautamaa- WWF Finland
You might be thinking, “why didn’t I know this?” Many of the benefits that freshwater fish provide people often go unseen. The lives of freshwater fish proceed underwater – often “out of sight and out of mind”. Freshwater fish are also not the most charismatic or photogenic ambassadors for the wildlife conservation movement. Their big eyes are more glaring than gazing, and, typically only making an appearance in the lives of the average American when on our plates, hopefully covered in a meuniere sauce.
Just in the US, recreational anglers have turned weekends spent casting into the rippling rapids in hopes of hooking a trout, into a thriving industry bringing in hundreds of billions of dollars to the US economy and creating nearly one million jobs. Around the globe, millions of people depend upon access to fish as a significant source of protein. Declines in freshwater biodiversity destabilize the intricately constructed web of life that makes up our planet. At the extreme, losing freshwater fish means millions of people losing access to food, fishery-based economies suffering, and a devastating extinction cascade effect that will leave healthy waters barren.

©Chris Bowser
The most reported cause of the decline found through the 2024 Living Planet Index update is habitat loss, seen in 50% of reported cases, followed closely by resource exploitation like overfishing. The hope in this crisis lies in its cause. We have the tools to act now and reverse the declines. Although many of the actions needed are large-scale and require concerted efforts, there are things that individuals can also do. For example, many local organizations host clean-up initiatives, efforts to re-connect or restore the flow of rivers, and native plant restoration for local streams and rivers. Volunteering for these initiatives is a great way to familiarize yourself with local waterways and be hands-on in their conservation.
Studies also show that spending time outdoors for at least two hours per week has long-term health benefits. So, while you’re improving the health of your river, you can improve your own health as well. If volunteer opportunities are limited, explore fishing, rent a kayak, or just take a stroll along a local waterway. Any time spent connecting with the rivers that sustain us is well-spent. As you gaze upon the surface of your local river, you may expect that there is a whole other world of life below the surface. It is up to us to maintain or restore the waters so that life is able to survive.
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