From Madison to Mongolia: The crusade for a giant fish

Biologist David Gilroy rides horseback on the frozen Uur River, a pristine body of water in the remote reaches of northern Mongolia. In the wild silence that blankets him, Gilroy listens for faint radio signals from below the river’s surface.

A graduate student, Gilroy hopes this month to begin detecting signals from a legendary fish species, one that has captured the hearts of scores of anglers. The scientist is on the trail of the majestic taimen, the largest trout species in the world.

Alongside fellow UW–Madison biologists and other American and Mongolian researchers, Gilroy is part of a five-year, $2.3 million initiative – largely backed by the Global Environment Facility – that aims to protect the endangered taimen by encouraging sustainable fishing practices. To that end, the researchers want to learn everything about the giant fish, from its migration pathways to spawning locations and population levels.

Amidst a booming ecotourism industry in Mongolia – with wealthy anglers paying up to $7,000 a week to catch taimen – the scientists launched the research project last year, in partnership with local nonprofit organizations, private fly-fishing outfitters and the nomadic peoples of the Eg-Uur watershed. Spearheaded by the Taimen Conservation Fund (TCF), a Mongolian faith-based nonprofit group, the goal is to empower local people and simultaneously promote awareness about the threatened fish and taimen-preserving fishing practices.

“The biology of taimen makes it sensitive to poaching,” says Jake Vander Zanden, a UW–Madison limnology professor and co-leader of the taimen research effort in Mongolia. “The fish is vulnerable because it grows slowly, reproduces at a late age and is a top predator.”

“Taking the taimen out of the river is like taking the wolf out of the forest,” agrees Gilroy.

In fly-fishing circles worldwide, the taimen is shrouded in mystique. Known to locals as the “river god’s daughter,” taimen can reach up to six feet and weigh up to 200 pounds. The fish can literally “explode” out of the water, snapping up small mammals in its wake, says Gilroy. Once prevalent throughout Mongolia and Siberia, over-fishing and habitat destruction have hacked taimen populations. Now, Northern Mongolia’s Eg-Uur River basin remains one of the last strongholds of healthy taimen populations.

Following detailed biological observations of the fish, Vander Zanden and Gilroy want to create a scientific framework that supports the creation of a catch-and-release fishing reserve. In catch-and-release fishing, sport anglers who catch taimen are obligated to return the fish to their native waters.

“A taimen is too valuable to catch just once,” says Vander Zanden. “Why not return it to the river so that it remains a sustainable resource that will provide jobs to the local people and help tourism businesses earn profits [in the long term]?”

Vander Zanden says the approach is starting to pay off as people realize that TCF’s blend of cultural preservation, natural resource management and species protection can be a win-win scenario for all interest groups.

As it stands, eco-tourism travel companies pay local resource management councils for permission to fish in protected areas. The councils, in turn, work with local government agencies, advocating for anti-poaching practices and catch-and-release fishing.

To boost protection efforts, TCF also works to revive religious and cultural values that stress the importance of respecting nature. By recently helping to reconstruct a once-prominent monastery, for instance, conservationists hope that revitalized Buddhist practices can bolster taimen populations.

During the project’s first year, the science team set up a research station and radio-tagged 50 fish. This year, the researchers will track the tagged taimen to start gathering clues about the fish and discern where populations may be most vulnerable, says Vander Zanden. “Ultimately, it’s biology that will determine where the protection reserves should be,” he says.

Research quest for giant fish goes global

If you’re flying all the way to Mongolia to help save one giant freshwater fish, why not go on a global quest in search of all the others?

Zeb Hogan, a UW–Madison postdoctoral researcher and a member of the taimen research team, in April will kick off an epic journey that touches on six continents and reaches ten of the largest river systems, from Southeast Asia’s Mekong River to the Amazon River in South America.

The goal is to find the world’s largest freshwater fish and investigate for the first time population declines worldwide. “Giant” fish include species that weigh more than 200 pounds and stretch longer than six feet. Certain species of stingray, catfish, sturgeon and salmon, for instance, all make the list. Hogan plans to track up to 30 species in all.

“The very largest [freshwater] fish seem to be in decline around the world. That is worrying because the biggest fish usually serve as environmental indicators,” says Hogan. “Similar surveys have been carried out with marine species, but nobody has attempted this with the world’s largest freshwater fish before.”

Hogan wants to compare past population levels to modern levels to quantify declines and pinpoint threats to freshwater biodiversity. Historical population data is sparse, however, so the researcher says he will mine both published and anecdotal literature, consulting old fishing logbooks, conversing with local fishermen and networking with regional conservation agencies.

“The exploration of freshwater ecosystems, rivers and lakes is every bit as important as deep sea habitats and coral reefs,” says Hogan. “Certain areas of Africa, Asia and South America are virtually unknown and very few rivers in remote areas have ever been surveyed, filmed or photographed.”

Mongolia is Hogan’s first stop. After helping with the taimen work, Hogan will push on to China, Thailand, Laos, Cambodia and Australia, before visiting African and South American rivers this fall.