Overview
The cutthroat trout are a native species to Yellowstone National Park. The trout are originally a Pacific drainage species, their travel into the Yellowstone area was likely through the Two Oceans Pass. In addition to being a native species to the park, the cutthroat trout are very important to the parks ecosystem. They feed on macroinvertebrates and are eaten by mammals and about 20 different species of birds. Cutthroat trout usually reach maturity at about 4 or 5 years old and once they have reached this point they spawn from February to May. The cutthroat trout can live for about 10 years, but they generally only live long enough to spawn once or twice.
In addition to the park having cutthroat trout, the park was also home to a deadly parasite that at one point in time lead to the death of thousands of fish, including the Cutthroat Trout. Tetracapsuloides bryosalmonae was a parasite that would cause the fish to get proliferative kidney disease, which would lead to abdominal swelling and also pale gills. This parasite in fact was so dangerous to fish that almost all fish obtaining the disease from the parasite would end up dying. In addition to the parasite killing off a large majority of the fish population, this also lead to the closure of an 183 mile long stretch of the Yellowstone River. When a section of a river that large gets cut off from human use, more than just the wildlife ends up getting affected too. Businessmen have said that during the couple of weeks that the river was closed, they lost upwards of $100,000, due to the lack of expeditions that were allowed during that time.
The increased presence of lake trout in Yellowstone National Park has been a problem people have been trying to solve since their introduction. The lake trout can live through two or three generations of the cutthroat trout and can grow to weigh four times more than the cutthroat trout. The lake trout spawn eight to ten years in a row whereas the cutthroat trout only spawn once or twice during its lifetime. The lake trout are overpopulating the cutthroat and making them go extinct. The lake trout produces 1,000 eggs per kilogram of their body weight. Some lake trout can produce 20,000 eggs. Once the lake trout are born, they are competing for the same food sources as the cutthroat trout. When the lake trout reaches four years old, they also begin to eat the cutthroat trout, which becomes half of their diet. An adult lake trout can eat about fifty of the cutthroat trout within a year.
The removal processes of the lake trout is the main effort to repopulate the cutthroat trout. One of the processes of removal for the lake trout is through deep water and spawner netting. This process involves dropping nets with the intent of catching lake trout to remove them from the environment. The deep water netting is used to catch younger lake trout before they reach sexual maturity. Spawner netting is used to catch the trout as the fish gather to spawn. In 2007, 63,776 lake trout were removed, but the lake trout population still continued to increase. We are looking to find out how the people who live in the areas near Yellowstone feel about the removal of these lake trout and whether they would want to contribute to their removal or any additional repopulation of the cutthroat trout.
Get Involved!
If you would like to contribute to our conversation about the repopulation of cutthroat trout or the removal of lake trout feel free to comment on our blog or use the hashtag #laketroutout on Twitter or Instagram. We will be continuing to gain and add information to our blog, so we welcome you to share any information you may find!
Additional Sources
“Yellowstone River Fish Kill Fact Sheet”
http://fwp.mt.gov/news/newsReleases/closures/waterbodies/nr_106.html
“Native Yellowstone Cutthroat Trout in Wyoming Need Your Help!”
http://wyomingtu.org/2014/01/27/native-yellowstone-cutthroat-trout-in-wyoming-need-your-help/
“Yellowstone Lake Cutthroat Trout Threatened by Non-native Lake Trout”
http://www.yellowstonepark.com/yellowstone-lake-cutthroat-trout-threatened-by-non-native-lake-trout/
“Preservation of Yellowstone Lake Cutthroat Trout”
https://www.nps.gov/yell/planyourvisit/upload/fishar9-18.pdf
“After thousands of fish die in the Yellowstone River, officials lift boating bans”
“Persistence of Tetracapsuloides bryosalmonae (Myxozoa) in chronically infected brown trout Salmo trutta”