In search of river giants

Rushing across a temple parking lot, British angler Rick Humphreys yells, “We’ve got a fish.”

He jumps into a small motorboat on the Mae Klong River in time to see Wirat Moungnum bring the prize to the surface: a rare giant freshwater stingray that weighs as much as 44 pounds.

It bursts through the murky water exposing a soft, white underbelly the size of a trash can lid. The crew scrambles to string a rope through its gill-like slits and wrap a towel around its 5-foot-long tail, which has a venomous barb.

“It’s a start,” Humphreys says almost apologetically. The specimen is a tenth the size of the largest rays. “There are a lot bigger ones than that.”

Humphreys is serving as a guide for American biologist Zeb Hogan, who is on a worldwide quest for the largest freshwater fish.

Hogan, 34, has heard the stories of Cambodian fishermen catching rays that weighed more than 1,100 pounds with wingspans of 14 feet. But so far they are just stories. If he can confirm them, his find could eclipse the world record now held by the Mekong giant catfish: a 646-pound specimen caught in 2005 in Thailand.

“It could be the largest fish in the world and we know next to nothing about it,” Hogan says. “I’ve spent five years on the Mekong looking for rays and only saw two or three. They were nowhere near the size I’d heard about.”

Hogan’s quest is part of the Megafishes Project financed by the National Geographic Society.

The three-year project, which started in 2006, aims to document and protect freshwater giants that weigh at least 200 pounds or measure at least 6 feet long. It will take Hogan to 14 freshwater systems on six continents, including the Mekong, Nile, Mississippi and Amazon rivers.

Time is running out for many of the species. The Chinese paddlefish and the dog-eating catfish in Southeast Asia are on the brink of extinction because of pollution, overfishing and dam building. In the Yangtze, where the Three Gorges Dam is a serious threat, Chinese paddlefish haven’t been caught since 2003.

“Of the two dozen or so species of giant fish, about 70% are threatened with extinction,” says Hogan, an assistant research professor at the University of Nevada, Reno.

Hogan dresses like a tourist, with a baseball cap and shorts, and has the boyish enthusiasm of an explorer. He spends much of the year searching for these large fish.

He has focused mostly on Asia, where he once traveled 36 hours by road to catch the taimen in Mongolia. He just returned from Bhutan, where he scoured river canyons for mahseer.

Hogan said he was drawn to the freshwater ray, known scientifically as Himantura chaophraya, because so little is known about it.

Listed as vulnerable by the International Union for Conservation of Nature, it is believed to be found in rivers from Thailand to northern Australia. Scientists discovered it only 18 years ago, and its population is unknown.

“I have so many questions about this stingray,” Hogan says. “Is it truly a freshwater species? Where does it breed? What are its migratory patterns?”

Hogan spent the last few years on the Mekong in a futile effort to catch rays because the nets of Cambodian fishermen were no match for them. Rays also are nearly impossible to spot because they spend much of their time scrounging for small fish, shrimp, crabs and mollusks that live on the bottom of muddy rivers.

A few months ago, Hogan got wind of big rays being caught and released by Humphreys’ company FishSiam in Thailand. Unlike the Cambodian fishermen, FishSiam uses modern rods and reels used to catch other big game fish. At first he was skeptical, then excited.

Humphreys seems an unlikely partner in Hogan’s quest. He has no scientific training. But he knows how to fish, and his team’s success in catching stingrays is almost unmatched in Thailand. Just in the last year, Humphreys and his partner, Wuttichai Khuensuwan, have caught 40 rays on the Bang Pakong and Mae Klong Rivers, with the largest weighing in at 485 pounds.

Humphreys, who got his start catching carp in West London gravel pits, says he prefers stingrays because of their fight. They routinely break fishing lines, he says, and one took 15 of his men about six hours to bring to the surface.

“Their strength is legendary,” he says. “When you see them in the flesh, it is quite humbling.”

Catching a ray can be dangerous, he says, especially before its tail has been neutralized. Wuttichai Kuachareonsri, a member of Humphreys’ crew, stopped fishing for a year after he was stung in the leg. “I never have felt pain like that,” he says. “It really frightened me.”

On his fishing trip with Hogan, Humphreys boasts about “monsters” below the tranquil river and insists that it is a matter of time before his team lands a world record ray.

The anglers head to the Bang Pakong and Mae Klong rivers just a two hours’ drive outside Bangkok, winding their way past office towers, Buddhist temples and busy highways. Fish farming pens dot the riverbanks, and sounds of construction and puttering boats echo across the water.

Both spots have given up rays in the past. But on the their first day on the Bang Pakong, the fishermen come up empty. Humphreys blames the heavy rains that have swollen the river.

The next day, they have better luck on the Mae Klong.

The rod bends almost into the water, and Wirat struggles for almost half an hour as the ray dives under the boat and across the bow.

It finally is brought to the surface, revealing its big bulging eyes and dark, coarse skin. Its tail alone is 12 feet long.

Hogan says catching such a big ray so close to a big city is a sign the species is thriving despite pollution. He is awaiting government permission to launch a two-year study to catch and tag 20 to 30 more rays to better understand their movements.

With the data, Hogan is hoping to do what he has done for the Mekong giant catfish, once almost fished to extinction. Hogan’s work helped establish its endangered status and prompted authorities in Laos and Thailand to limit total catches to four a year.

Chavalit Vidthayanon, a freshwater biologist at the World Wildlife Fund who discovered a smaller ray species in Thailand four years ago, agreed that more research was needed to better understand the health of the big fish.

“We need to know its exact population and habitat so we can work on conservation and find ways to better protect them,” he said.

For Hogan, the research could help end what has become an epic journey to find “the king of the river.”

“We’re getting close to the record and I’m very confident that a fish of record size existed,” he says. “The question is whether it still exists.”