Global biodiversity in freshwater is under pressure. Fish and humans have been connected since ancient times. Still, we know relatively little about how these animals fare underwater. "Studying the behaviour and ecology of fish enables us to become spokespersons for these valuable animals", says Prof. Dr Tom Buijse, in his inaugural address as a professor, by special appointment, Freshwater Fish Ecology at Wageningen University & Research.
Freshwater ecosystems hold the highest levels of biodiversity. Hundreds of millions of people across the globe depend upon these ecosystems for their nutrition. Vulnerable communities even more so. Freshwater fish are crucial to the health of many different ecosystems and support food webs. At the same time, the World Wildlife Fund (WWF) estimates that the world's freshwater biodiversity has decreased by over 80 per cent since 1970.
What fish need
"What happens below the surface often still is a mystery", says Buijse. "Thus, what fish need is not visible and calls for research. By meeting the fish's requirements, we can contribute to the conservation and recovery of the ecological resilience of inland waters."
This is one of the reasons why Buijse values research such as that conducted by Twan Stoffers, which maps how different species of river fish use the Dutch floodplains. To improve the ecological functioning of inland waters for freshwater fish, their connectivity and habitat diversity must be enhanced. Easier said than done, according to Buijse. "Climate change has rendered research results from the past less reliable for present-day scenarios, not to mention predictions for the future."
Linking freshwater research to the marine domain
The professor also strives to link freshwater research to the marine domain, particularly as a new bachelor's in Marine Sciences is to launch at WUR in September. There are, after all, many similarities between the issues within the marine and freshwater environments.
Moreover, migratory fish, such as the Atlantic salmon and the European sturgeon, require both the marine and freshwater environment to complete their life cycle. Buijse: "And these are precisely the species that are threatened. What they need are so-called swimways , similar to flyways for birds."
Joint research with stakeholder groups
Precisely by virtue of its invisibility, policymakers and the public at large frequently lack knowledge about underwater conditions. That is why Buijse aims to collaborate with stakeholder groups and other interested parties. There are over 700 thousand recreational anglers in the Netherlands, a potentially fine-meshed network of observers. Additionally, professional fishers may serve as the eyes and ears for researchers throughout the year for what happens in and on inland waters.
