Battle for the Blue: Colorado's "Jurassic Park" Controversy

A billionaire’s trout playground known as “Jurassic Park” may be Colorado’s first permitted float-fishery if a proposal by Blue Valley Ranch and the volunteer organization Friends of the Lower Blue River moves forward on the Blue River.

The 2,000-acre ranch, owned by billionaire Paul Tudor Jones II, gained public attention decades ago with its in-stream trout habitat improvements and its incredibly large trout, which grow fat on a diet of pellets.

Access to the ranch waters has always been restricted due to Colorado law that gives ownership of the streambed to private landowners. The public cannot wade on private land, but in recent years, fishermen have been using rafts to float the lower Blue River between Green Mountain Reservoir and a takeout near the confluence of the Colorado River. Social media influencers have been catching these “Jurassic-sized” pellet-fed trout for online clout, and the river has been become more popular for anyone with a raft.

Land Swap

In January 2025, the Bureau of Land Management completed a land swap with Blue Valley Ranch that traded nine parcels of federal land totaling 1,489 acres in Grand County for nine parcels of private land totaling 1,830 acres in Grand and Summit counties. The deal was promoted by the federal government as a way to reduce “checkerboard” land ownership and the ranch agreed to cover the costs of river restoration work for a three-quarter-mile stretch of the Blue River near its confluence with the Colorado River, pay for the creation of a new Confluence Recreation Area with more than 2 miles of new walking trails and wheel-chair accessible fishing platforms. All of this “new" public access is to water outside the ranch boundaries. The ranch itself improved its position in regard to contiguous ownership of the riverbed in the coveted area where the ranch stocks trout that grow surprisingly large.

Now that the land swap is complete, Friends of the Lower Blue River (FOLBR) has proposed a permit system that would apply only to floating fishermen.

“The Lower Blue River, long recognized as one of the greatest trout fisheries in the world, is at a crossroads,” explains the Friends of the Lower Blue River’s website folbr.org. “With increase in use, so have the fishing pressures on the river. … Fish populations are declining, and the river’s world-class trout fishery is quietly slipping away.”

According to FOLBR, the Lower Blue River has seen an increase in angling use that on peak days is as high as 30 to 45 boats per day. Trout quantity is presently at just 43 pounds per acre compared to what was once 400 lbs per acre (1,992 fish per mile). These numbers come from Blue Valley Ranch video surveillance and from Blue Valley Ranch fishery biologists.

According to FOLBR, the way to save the river's trophy-size trout is 10-year pilot program to limit floating fishermen on peak days. Nonfishing boaters would not need a permit, nor would anglers who have legal right to walk on the private property that ensconces the river. According to FOLBR’s proposal, the  goal would be 4 to 9 boats total on peak days.

By Blue Valley Ranch’s own numbers, float fishing on the Blue Peaked in 2020 with 1,202 total boats annually and has dropped in subsequent years, falling to 442 total boats and 358 total boats in 2024 and 2025 respectively.

Health Problems

Ben McCormick, owner of Cutthroat Anglers a fly shop in nearby Silverthorne, says that the dropping trout numbers have little to do with boat traffic and are indicative of larger water quality issue in the lower river.

"The ranch has finally admitted the river has a health problem, this is an opportunity for us to expose what is going on down there,” said McCormick. "With this whole permit proposal, there’s no recognition of the unnatural occurrences that are happening within the ranch.  There's mention of pellets, no mention of diverting water into side channels, no mention of all the weirs they have in the river. I believe the declining health of the river is almost entirely due to what the ranch is doing to the river.

“I find it kind of kind of funny that they are complaining about flows from Green Mountain Reservoir, when they have dug their own private side channels and a large pond. All these things affect water temperatures and water quality."

And McCormick argues that the repetitive V weirs and other manmade trout-habitat structures the ranch has deployed are bad for the overall health of the river.

“The structures they have built in the river provide holding water for large trout but give no consideration for spawning habitat or for small trout,“ said McCormick. In essence they have destroyed natural trout habitat and built a river suitable only for adult stocked trout. I’m tired of the narrative that Blue Valley Ranch is fixing the river... they are destroying it. They are constantly in there with heavy equipment... it’s not restoration, it’s destruction."

McCormick says Blue Valley Ranch has always stocked trout in their part of the Blue River, and their pellet-feeding program also creates biological and ethical problems.

"I’ve seen pellets floating on the river all the way down to the confluence with the Colorado River and I have videos of it,” he said. "Chumming is illegal in Colorado, so how are they allowed to do this? And if the ranch is chumming, are floating fishermen partaking in that? Who is breaking the law? I have heard of people bringing their own dog food with them to catch those big fish. It’s a horrific place in my opinion."

"The public should be angry that these landowners can put whatever they want into the river and get away with it," said McCormick. "It irks me to the bone because at the same time they are making it harder to float and fish the river, and what they are doing is ruining it for everyone.”

McCormick is gathering names on a petition titled “A Call to Safeguard Native Fish and Biodiversity by Prohibiting Fish Feeding in Waters of the State.” In the petition he states that it’s illegal to feed big game like elk and deer in Colorado because it’s unethical, and biologically leads to concentration of animals and disease. He believes the same rules should apply to Colorado rivers.

“By feeding fish, we are also introducing nutrients into watersheds that may violate the Clean Water Act. The excess nutrients may lead to increased algae blooms, which reduce invertebrates, juvenile fish, and spawning,” the petition states. The is a link to the petition on his blog at fishcolorado.com.

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Ross Purnell is Fly Fisherman's editor and publisher.

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