UNR biologist, National Geographic Explorer helps tag rare freshwater monster fish in Cambodia

As Cambodians celebrated Independence Day on Monday, Nov. 9, fishermen near Phnom Penh made a very special catch befitting the occasion: a rare Mekong Giant Catfish, also known as the “royal fish” because of its enormous size.

“This is really extraordinary,” Zeb Hogan, a University of Nevada, Reno biologist and a National Geographic Explorer who has studied the Mekong Giant Catfish for almost 20 years, said. “It confirms that this incredibly rare and critically endangered freshwater species still occurs in Cambodia and it is still making its annual spawning migration out of the Tonle Sap Lake and into the Mekong River.”

It was the first reported catch in Cambodia this year of the elusive giant catfish, according to Department of Fisheries officials in Phnom Penh.

“At just under 7 feet in length, the catfish was larger than any catfish that has been caught in the U.S. in the last 100 years,” Hogan, a research assistant professor in the University’s College of Science and host of Nat Geo WILD’s Monster Fish show, said.

In 2005, a Mekong giant catfish was caught in northern Thailand weighing in at a whopping 646 pounds, still believed to be the largest freshwater fish ever caught.

This latest, special catch happened as Hogan prepared to commemorate the Nov. 14, 2015, opening of the National Geographic exhibition, “Monster Fish: In Search of the Last River Giants,” at the Terry Lee Wells Nevada Discovery Museum in Hogan’s hometown, Reno, Nev. The traveling museum exhibition’s six-month stay in Reno is sponsored by the University’s College of Science and follows its debut at National Geographic headquarters in Washington, D.C.

As word of the surprising catch in Cambodia spread, dozens of people gathered at the riverbank just north of the capital to sneak a peek at the seldom seen giant and snap selfies to capture the event. Hogan and officials from the Cambodian Department of Fisheries tagged the fish to track its future movement before guiding it to the middle of the river to be released. Hogan, who dove down about 10 feet with the fish to help its return to deeper waters, said the fish seemed to be in good condition.

“Swimming with the fish was incredible as always,” said Hogan, who has swum with dozens of huge fish as part of his research. “This particular fish was in better shape, not as injured, than most, so that makes me optimistic it will survive. What was really incredible is that I happened to be visiting at the time of the catch. It’s a one-in-a-million opportunity.”

The gigantic fish was tagged and released alive, just downstream of fishing nets as part of a research and conservation project supported by the Cambodian Department of Fisheries, the University of Nevada, Reno and National Geographic. The catch-and-release illustrates that fishermen can be valuable partners in conservation efforts.

“Without monitoring we have no way of knowing how the fish are doing,” Hogan said. "Just like elephants, tigers and polar bears, these fish are iconic animals that have an almost mythical status in the Mekong region.”

“The giant catfish holds a special place in Cambodian culture,” Thatch Phanara, a biologist with the Cambodian Department of Fisheries who assisted with the release, said. “Fishermen sprinkled water on it to wish it good luck.”

There are 3,000-year-old cave paintings depicting the giant catfish in Thailand and elaborate ceremonies have been associated with its capture for centuries. One fisherman involved with the catch blessed the fish by sprinkling brightly-colored flower water on the fish before its release.

“The Mekong Giant Catfish was once caught by the thousands,” Hogan said. “But it’s so rare now that the survival of every fish makes a difference; survival of migrating adults is especially important. With ongoing changes happening on the Mekong River that may cause the extinction of the giant catfish, measures to study and protect these fish are more important than ever.”

Hogan has been finding, studying and protecting the world’s largest freshwater fish for 20 years with his megafishes project, and chronicling the research with the Nat Geo WILD “Monster Fish” television series, now in its sixth season.

Of the National Geographic exhibition “Monster Fish: In Search of the Last River Giants,” Hogan said: “The exhibition summarizes the last 20 years of research; it's an educational tool that we can use to build momentum for the conservation of these extremely rare fish. The catch shows why the exhibition is important: to take what we learn in the field and share it with millions, including, now, people locally in Reno and the Western United States.”

“Lessons we learn in the Mekong are not all that different than challenges we face here at home in Nevada and across the United States,” he said.

In the photo: Biologist and host of the Nat Geo WILD “Monster Fish” show, Zeb Hogan, was on hand to assist Cambodian fisheries officials tag and release the rare Mekong Giant Catfish after it was caught Monday, Nov. 9 on the Mekong River.

— Mike Wolterbeek is the Communications Officer for the University of Nevada, Reno. He can be reached at mwolterbeek@unr.edu