Saturday, November 20, 2004
A new fish management strategy undertaken by the Colorado Division of Wildlife seems to be successful in managing trophy pike in Stagecoach Reservoir while maintaining a healthy supply of fat rainbow trout for the crowds of summer campers and anglers who visit the state park.
DOW biologist Billy Atkinson spoke about the new strategy during a small gathering at the Carpenter Ranch on Wednesday.
Although the DOW did not place pike in the reservoir south of Steamboat, the fish are there, and the possibility of catching pike in the 30- to 40- inch range in Stagecoach thrills many anglers. However, after the feeding frenzy of June, the big fish go deep in search of colder water, Atkinson said. By the time the park is at its busiest in July and August, the pike are no longer catchable for most anglers.
During the 1990s, the DOW stocked fingerling trout in Stagecoach, an exercise that amounted to feeding the pike, Atkinson said. In June 2001, he placed a series of six gill nets extending from the shore of Stagecoach into the lake to sample fish populations. The nets are 6 feet tall and 150 feet long. He places them in the same location very June. In 2001, the nets produced just two trout longer than 14 inches.
In November 2001, Atkinson tried a different strategy. He and his colleagues returned to stocking trout in Stagecoach, but this time used trout that were 12 to 13 inches long instead of stocking fingerlings.
Atkinson knows that by November, pike are feeding at just one-tenth of the rate they do in June. Atkinson also knows that pike are capable of eating other fish that weigh up to 45 percent of their own body weight. That means smaller pike can't victimize trout in the 13-inch range.
And by the time the pike resume their voracious eating the next June, the stocked trout stocked should have grown to almost 15 inches. It takes a 31-inch pike to eat one of those trout.
"We're able to manage for trophy pike, but stunt those under 30 inches," Atkinson said.
After just one winter, the fisheries biologist was beginning to see the results of the new strategy. In June 2002, he found found 70 trout longer than 14 inches in his nets. The number in 2003 dropped back to 65. Although the samples taken in the gill nets are just a small fraction of the total number of larger trout in the lake, they provide a good gauge of the reservoir's overall fish population.
Atkinson's research also has found signs that northern pike in the Yampa River upstream from Steamboat Springs are eating themselves out of a living. He recently found a 7-inch pike inside the stomach of a 30-inch pike.
"Cannibalism is a sign of very limited forage (small fish of other species) in that section f the Yampa," Atkinson said.
Atkinson recently sampled the stomach contents of the large pike as a result of an electro-shocking operation he conducted with volunteers along an 800-foot section of the Yampa upstream from Steamboat in the Chuck Lewis State Wildlife Area.
The purpose of the operation wasn't to kill pike -- electro-shocking when done properly, temporarily stuns the fish and doesn't harm them -- instead he was trying to gather data about the distributions of species, and age classes of fish in that small stretch of the river.
Atkins said he has learned that pike are faring well in the relatively quiet stretches of the Yampa upstream and downstream from Steamboat Springs. The prey fish within that small section of the Yampa encompassed by the Chuck Lewis Wildlife Area previously included fingerling trout stocked by Atkinson and his colleagues. He's learned it doesn't pay to stock small trout in the wildlife area because they just become food for the pike.
"More and more of my (fingerling trout) the last three to four years were not showing up," during annual electro-shocking efforts, Atkinson said.
Pike aren't having nearly the same effect in the swifter waters within the city limits of Steamboat, Atkinson said.
"We're seeing all age classes of trout, and the growth rate is good," Atkinson said. The browns are doing very well, as are the Snake River cutthroats."
Trout stocked as fingerlings stocked in the town stretch in 2001 can be as large as 15 to 16 inches now, he said.
One thing that is not happening in the town section of the Yampa is "recruitment," of native fish through natural spawning. The temperature of the river water gets too warm, too early, for spawning to succeed, Atkinson said.