Idaho Moves to Constrain the Impact of Rainbow Trout on Native Cutthroat
IDAHO FALLS- Since 1982, fisheries
biologists from the Idaho Department of Fish & Game (IDFG) have been
monitoring the numbers of the different types of trout found in the South Fork
of the Snake River outside of Idaho Falls, Idaho. This monitoring has tracked
the impact non-native rainbow trout are having on native Yellowstone cutthroat
trout populations. Rainbow trout can interbreed with cutthroats and produce
fertile offspring. The resulting generations of hybrids become more and more
like rainbows, and less like cutthroats. While a variety of efforts have
yielded some success, 2009 counts showed a dramatic increase in the number of
rainbows that were spawned in 2008, prompting the need for some serious action.
IDFG hopes its South Fork Snake River Angler Incentive Program will increase
the harvest of rainbow trout, reduce their numbers, and help to protect native
Yellowstone cutthroat trout.
The goal of these management efforts is not to eradicate the non-native rainbow trout, but to reduce their numbers to what was seen on the South Fork in the 1980's and early 1990's. Monitoring in 2009 showed for the first time since 1982, that rainbow trout outnumbered Yellowstone cutthroat in the South Fork of the Snake River. The major focus area is the stretch of river below Palisades Dam down to Heise. This portion is important, because it includes the four main spawning tributaries used by Yellowstone cutthroat trout. More information will be forth coming on the important work being done to protect these vital creeks.
Ongoing efforts to reduce negative
impacts by removing size and bag limits for rainbow trout have been proven to
work during normal years, but 2008 was not your typical year. The timing of the
spring flows was such that it did not scour away rainbow spawning beds created
in the main river channel. Education efforts and modified regulations helped to
decrease the number of fish being released to 50%. Unfortunately, this still
resulted in too many rainbows being released to be able to go on and reproduce.
According to Fishery Biologist Brett High, "We think that if we can
decrease the percentage of fish released, then we will be able to make a
difference on the rainbow trout populations in the South Fork."
In order to obtain such a target, IDFG joined forces with Trout Unlimited to design a project that would get anglers to want to harvest every rainbow that they landed. The South Fork Snake River Angler Incentive Program hopes to change the way anglers respond whenever they catch a rainbow, ultimately helping to prevent the native Yellowstone cutthroat trout from disappearing.
Humans love a challenge and they enjoy being rewarded. Combine the two and you hopefully have the recipe for success. The challenge is the aquatic equivalent of finding a needle in a haystack. In this case, 575 rainbow trout of varying sizes have had tiny wire "tags" implanted in their snouts. These tiny wires are etched with microscopic markings to indicate their value. No state dollars are being used for this program, only money from Federal sources. The reward breakdown is as follows: 300-$50, 200-$100, 50-$200, 20-$500, and 5-$1,000.
competitive aspect is that the tags are invisible to the eye and cannot even be
detected by a standard metal detector. In order to tell if a fish is a winner
it must be killed and brought into the Idaho Falls IDFG headquarters to be
checked. Because the rainbow trout is a sport fish, it cannot be wasted!
Anglers can keep the meat and turn in the head if they desire or they can turn
in the whole fish. IDFG has worked out an agreement with the Eastern Idaho
Community Action Partnership (EICAP) who will distribute the donated fish to
the needy. Because all of these fish are destined for human consumption, it is
critical that they are treated in a manner that will preserve their freshness
and cleanliness. All fish need to be killed immediately and then cleaned. After
being cleaned, they need to be stored in an appropriate manner for consumption.
Heads can be separated from the bodies and both frozen until they are turned
It is important for anglers to be aware the process to determine whether a fish is a winner and receive a check will not happen overnight. Fish can be dropped off during business hours at the IDFG regional office located at 4279 Commerce Circle in the St. Leon Business Park in Idaho Falls, or later in the spring and summer at freezers placed at the Conant and Byington Boat ramps. Anglers may also bring fish to the IDFG regional office on the first Friday of each month. Biologists will then use an ultra-sensitive metal detector to determine if a fish has a winning tag.
Once tags are located and removed they will need to be examined under a microscope to read the code indicating the reward amount. "People won't just be able to bring in a fish and get a check; the whole process will take about a month." said High. Anglers will receive receipts for fish they drop off. If they would rather see with their own eyes if they have a fish with a wire tag, then they will have to come to the regional office on the first Friday of each month when fish are checked. "Again, even if their fish is a winner, the process to locate and then issue a reward check will take some time." said High. IDFG policy prohibits employees from taking part in the program that will run through the end of 2011.
To learn more about this program, please call the regional office at 208-525-7290. A brochure will soon be available about the program or you may view a short YouTube video about the program at http://www.youtube.com/user/idahofishgame .