As U.S. Fish and Wildlife officials determine whether the Yellowstone cutthroat is deserving of federal protection under the Endangered Species Act, a debate rages over whether a certain population of the fish are actually a separate subspecies.
Yellowstone cutthroat are the native species of trout in the Greater Yellowstone Ecosystem, which is roughly the size of West Virginia.
While they're on the rebound in some areas, they still occupy only a fraction of their historical habitat that encompasses the upper Snake River and Yellowstone River basins.
Some want the fish listed, while others, especially state Fish and Game officials, frown on a listing, largely because they don't want federal officials trampling on their turf and tweaking their efforts.
Complicating matters are visible and potentially genetic differences between some Yellowstone cutthroat, which is one of 14 subspecies of native Western cutthroat.
The Snake River, which forms in western Wyoming before flowing into eastern Idaho, is home to a native population of Yellowstone cutthroat. But there may actually be two different subspecies.
From Jackson Lake, the Snake River flows south before curling west, crossing the Idaho border and spilling into Palisades Reservoir. The Yellowstone cutthroat in this stretch of river are often referred to as Snake River fine-spotted cutthroat. In the Snake River above Jackson Lake and below the Palisades Reservoir, in what's known as the South Fork of the Snake River, the Yellowstone cutthroat have far fewer and much larger black spots. The spotting differences are easily detectable, as is another physical characteristic: the fine-spotted cutthroat is bulkier with noticeably larger shoulders.
Scientists claim there is no genetic difference between the fish, while others counter there is and the gene or genes just haven't been found yet.
"I'm sure one day someone will find the differences, we just haven't looked at the right genes to see the differences yet—there are a lot of genes to look at," said Lynn Kaeding, head of the U.S. Fish and Wildlife Service's Native Fishes Management program in Bozeman, Mont. "There are differences, I don't think we would argue otherwise."
Kaeding is so certain that the fish are different subspecies that he has taken to labeling the fine-spotted cutthroat the "Behnke cutthroat," after Dr. Robert Behnke, who is widely considered one of the premier authorities on trout and salmon.
Behnke feels the differences between the fish are so obvious that genetics have become a moot point.
"It's common sense without genetics," he told a room full of scientists and trout enthusiasts during a Yellowstone cutthroat symposium in Idaho Falls in October. "We often spend too much time on minor matters that aren't important at the time. When you get to the point of doing genetics just to do genetics ... you're getting on the wrong track."
But given the circumstances of the Endangered Species Act, the genetic differences may be important. The fine-spotted cutthroat is flourishing, while the rest of the Yellowstone cutthroat population is in the gray—some are on the comeback while others are suffering.
And environmental groups, which won a lawsuit against Fish and Wildlife in 2004 after the agency determined a listing wasn't warranted, didn't distinguish between the fine-spotted and large-spotted cutthroat in their petition, which Fish and Wildlife officials must follow in their current ESA examination.
"They lumped the large-spotted and fine-spotted cutthroat together; they didn't make a difference between the two," said Kaeding, who is largely responsible for determining whether the Yellowstone cutthroat will be listed.
Therefore, the overall population of Yellowstone cutthroat is stronger with the fine-spotted cutthroat in the mix, and the chances of a listing diminish.
But Keading concedes that it's probably better at this point to consider the two together.
"We probably would be headed for trouble if we looked at the large-spotted and ignored the fine-spotted," he said.