Outdoors

River Monsters Disappear

The fate of Montana’s freshwater megafauna is threatened by the same problems as the rest of the world’s giant fishes

The Missouri and Yellowstone rivers in eastern Montana support a self-sustaining population of paddlefish. While these ancient fish are blinking out of existence in waterways all over the planet, in Montana the paddlefish population remains healthy enough to support a snag-and-take fishery, though anglers are limited to one per season.

Paddlefish are the largest gamefish in Montana. The state record is 142.5 pounds, and a 198-pounder was speared in an Iowa lake. Since paddlefish are filter feeders and eschew bait, anglers have to snag the giants.

If you’ve ever foul hooked a 16-inch rainbow and were temporarily fooled into thinking you’d connected with the trout of a lifetime, you have an idea what the fight of a snagged 50-pound paddlefish must be like.

The news isn’t so good for an even larger cousin of Montana’s giant. In January, the Chinese paddlefish, last seen in 2003, was declared extinct. Unconfirmed reports suggest the Chinese variety grew up to 23 feet long, and it was once found in rivers across that country. But the usual suspects — dams, overfishing, diminished water quality and quantity — doomed what might have been the biggest freshwater fish on the planet.

The Chinese paddlefish is now gone, and it’s not the only freshwater giant struggling to survive. A research paper just published in Global Change Biology states that freshwater megafauna (freshwater animals that can reach 66 pounds) declined by 88% across the planet from 1970 to 2012.

There are 126 such species, including a few mammals and reptiles. But mostly freshwater megafauna are fishes: huge catfish, sturgeon and giant stingrays.

Montana has two additional freshwater megafauna, the white sturgeon in the Kootenai River and pallid sturgeon, which shares the Missouri and Yellowstone with paddlefish.

The Flathead’s great gamefish don’t quite measure up. The state record lake trout is 42.69 pounds. But lake trout are capable of growing to megafauna status elsewhere. The record is a 72-pounder caught in Great Bear Lake in the Northwest Territories. And an 83-pounder was also hauled from Great Bear, though since it was caught in a gill net by subsistence fishermen it didn’t qualify for the record books.

I don’t know if there are 66-pounders swimming in the depths of Flathead Lake, but I suspect a lot of Flatfish lures have been lost by anglers trolling the depths trying to find out.

The state record bull trout is 25 pounds and was caught in 1916. The world record bull trout is a 32-pounder caught in Idaho’s Lake Pend Oreille.

One other Montana fish is knocking on the door of megafauna status: the bigmouth buffalo. The state record is a 57.75 pound fish caught in 1994 in Nelson Reservoir near Malta. The world record for the species, the largest member of the sucker family, was a 70-pounder caught in Louisiana in 1980.

The fate of Montana’s freshwater megafauna is threatened by the same problems as the rest of the world’s giant fishes. Dams have altered much of the state’s waterways, though the paddlefish and sturgeon are hanging on in the free-flowing Yellowstone. In the Flathead, however, non-native lake trout are probably limited from achieving megafaunal status by the system’s limited food supply.

All of this megafauna decline is taking its toll on the television industry as well. “River Monsters” was a cable hit until it was canceled two years ago. The show was a not-so-guilty pleasure of mine. I often watched, but I found host Jeremy Wade’s antics a little silly. His shtick was to narrate in a hushed, grave tone that suggested he was about to engage in mortal combat, rather than go fishing.

Sadly, the mortal combat is reserved for the river monsters themselves. Their opponent is modernity and the continued industrialization of nature.