Thursday, December 17, 2015

The Cherry Creek Effect: Cutthroat comeback in the Lower Madison

Photo by Liz Juers
Have you noticed a change in your Lower Madison River catch?

For as long as I've fished the Lower Madison - about 10 years - it's been a rainbow and brown trout fishery. Nary a whitefish, much less a brookie or cutthroat. It's never been a place to catch native fish, save for the extremely rare arctic grayling or Utah chub.

But now you can actually expect to catch Westslope cutthroat in the Lower Madison (below Ennis Dam), thanks to the reintroduction project on Cherry Creek, a major tributary. While the Cherry Creek project has had its issues, it now appears to be thriving, so much so that the reintroduced trout are apparently overflowing into the Madison River about eight miles downstream of the stocking site. Reports of pure (in appearance anyhow) cutthroat trout began last spring, and in the past month, have become commonplace from Bear Trap Creek to Greycliff. Anglers have reported as much as 20 percent of their catch being cutthroats or cutt-bows.

"Typically resident populations of westslope cutthroat trout above fish barriers have a very slow rate of emigration, maybe 2 percent a year," said Dave Moser, Fisheries Biologist from Montana Fish Wildlife and Parks. But empirically at least, they seem to be pouring in a little faster than that. Three of three queried anglers agreed that the cutthroat tallies have been way up.

"I’ve noticed that when westslopes are introduced to historically fishless habitats they initially exceed carrying capacity of the stream – over time these populations will self regulate and less fish may out-migrate," Moser added. "Cherry Creek holds enough fish (>25,000 fish) that, if out-migration is greater than 2 percent it would be quite noticable. Cutthroat in general are more catchable than browns, rainbow trout, and brooks. Also, since these fish are entering new habitat this may enhance their catchability."

Anglers are psyched about the new possibility.

The "Lower" has traditionally been, and still is, a rainbow-dominant fishery.
"It is an awesome development and good to see a project on private lands benefiting the general public," said angler and friend Ben Pierce. 

Beyond the opportunity to again catch a native trout in the Madison River, the influx of cutts should be relatively innocuous to the fishery. 

"These excess or migratory fish would likely have little impact on the current fishery," Moser said. "There is some overlap with spawning of rainbows but they hybridize – so no net loss of biomass there. Smaller westslope would likely be prey items for browns. Competitively, browns and rainbows would have the advantage. Also given the populations sizes compared to outmigration from Cherry Creek – it is really a drop in the bucket."

Related story: Do native fish pay? (page 30)
Related: Reintroduction goes awry
Related: Climate change and native trout


Lester Kish said...

Josh, I've also noticed an increase in the number of cutthroats in DePuy Spring Creek in the past couple of years. Perhaps they're indicative of increased numbers of cutthroats in the Yellowstone as well.

Coincidentally, I was looking through some old (1980) slides over the weekend. They were taken at Cherry Lake. As I recall, the fishing was quite good for nice healthy cutthroats way back then. It was, and still is, quite a haul by foot or horse.

Josh Bergan said...

Interesting about Cherry Lake. I had plans to get up there, but lost the motivation when I learned it's something like 8 or 9 miles by foot. I'd also gathered that the fish were nothing special, but if you say they're nice fish, maybe I'll reconsider... Thanks for the tip.

Lester Kish said...

Hey Josh, if those fish are still alive they'd have beards and look like the guys in ZZ Top. I was up there 35 years ago. Let me know if you go, and do take a picture of those bearded trout.