Dozens of Amazonian fish glided overhead in an aquarium as scientists and policymakers from around the world sat below, discussing the future of migratory species that cross borders and continents.
ҹɫÊÓƵ graduate student Zach Bess sat in the glow of Brazil’s Bioparque Pantanal — the world’s largest freshwater aquarium — and watched as research he’d worked on was presented on a global stage. Bess was part of an international team presenting the “Global Assessment of Migratory Freshwater Fishes,” a United Nations report released at COP15, the shorthand for “15th Meeting of the Conference of the Parties to the Convention on the Conservation of Migratory Species of Wild Animals.”
“It was a cool place to see the work come to life,” Bess said. “A chance for the work we had done to really shine.”
A global assessment with urgent findings
The report, co-authored by Bess, his adviser, biology professor Zeb Hogan, and a team of researchers, marks the first comprehensive review of migratory freshwater fish in more than 15 years. It draws on datasets and conservation assessments covering nearly 15,000 species and its findings point to a severe biodiversity crisis: migratory freshwater fish populations have declined by approximately 81 percent worldwide since 1970.
Their report identifies 325 migratory freshwater fish species that may qualify for international protection because they depend on rivers and lakes that cross national borders.
Many of these species are essential to healthy systems and fisheries, yet do not receive the attention terrestrial and marine species do in international conservation agreements.
“Many of the world’s great wildlife migrations take place underwater,” Hogan said in the Convention on the Conservation of Migratory Species’ assessment materials. “This assessment shows that migratory freshwater fish are in serious trouble, and that protecting them will require countries to work together to keep rivers connected, productive and full of life.”
Connecting science and policy
Even as a graduate student on the team, Bess contributed to extensive data analysis for the report. He analyzed information from global species databases, scientific literature and expert input.
“It highlights the need to bring more countries, especially in Southeast Asia, into CMS if species are going to be protected,” Bess said in an interview with Mongabay, which was also published by .
For Bess, attending COP15 in Brazil was professionally and personally formative.
“I was a little nervous about the language barrier going there,” Bess said. “But I was surprised by how many people spoke English, and how easily you could get by just communicating in simple ways.”
Inside the conference, Bess said the scale was striking: more than 1,000 participants representing countries from around the world, all working toward shared conservation goals.
The most defining moment for Bess came during the official launch of his team’s assessment at Bioparque Pantanal. As collaborators presented the findings, fish swam overhead, offering a visual reminder of the ecosystems at the center of the discussion.
“Watching the fish swim from one side to another, while the team presented was a neat chance to see the work I’d done really shine,” he said.
Looking ahead
Now back in Reno, Bess is working to translate the assessment into peer‑reviewed scientific publications. He will also continue his research on food web ecology in Lake Tahoe and Donner Lake, as well as conservation status assessments for Nevada’s native fish species.
As global attention to freshwater biodiversity grows, Bess’s work reflects how ҹɫÊÓƵ graduate students are contributing to research with implications far beyond the region and helping inform policies that may shape the future of rivers, fisheries and communities around the world.
