Cutthroat Trout Essay

In Yellowstone National Park, there are more than 11 native fish species in the waterways, with the Yellowstone cutthroat trout historically being the most abundant fish in the park (NPS, n.d.). The cutthroat has been the dominate fish species in this area for hundreds of years, being fished by both the Native Americans who lived in this area and the wildlife. This fish is an integral part of Yellowstone’s ecosystem because they are relied upon as a keystone food source for birds, bears, river otters, wolves and other mammals inhabiting Yellowstone. Because cutthroat trout spawn in shallow rivers upstream like salmon, they are easy to catch and consume by mammals and birds. This food source is crucial to ensure the continuation of other species. Bears, wolves and large prey birds are less likely to hunt for smaller prey or juvenile animals if there is an abundance of cutthroat trout available. With the introduction of non-native fish, specifically lake trout which prey on native fish, cutthroat trout have been decimated for over a hundred years to the point of almost extension (Duncan & Zale, 2009). This has caused an imbalance to the ecosystem, causing other species to begin hunting other animals as an alternate food source. With the declining population in cutthroat trout, young elk, moose, and deer deaths have been on the rise in the park due to bear and wolf attacks (Schullery & Varley, 1995). This cycle has shown to decimate the younger animals, which in turn, is causing a chain reaction and lead to a breakdown of this fragile ecosystem. Since 1994, when lake trout was discovered in large populations, scientists have been coming together in workshops and conferences to determine the best mitigation measures for controlling lake trout populations and raising the numbers of native cutthroat trout back to acceptable levels. These workshops are allowing the scientist to see if their methods are having positive results in declining lake trout population and improving cutthroat number. Consistent methods that have shown encouraging results are gill netting. Gill netting allows fisherman to harvest lake trout while releasing cutthroat trout caught. By catching and monitoring lake trout, scientists and are seeing a positive comeback of the cutthroat trout. Yellowstone cutthroat trout had occupied a greater area than any other inland species of cutthroat trout in the United States with almost 18,000 stream miles being inhabited (Duncan & Zale, 2009). Cutthroat trout had no other predator fish species to compete with and was the dominate fish living in Yellowstone Park. In the late 1800s, park superintendents felt that the waters in the park was being overfished by the wildlife, so the US Fish Commission was directed to stock all waters with non-native fish to ensure tourists appreciated the abundant fishing opportunities and bring in more tourism (NPS, n.d.). Four species of trout, brook, brown, lake and rainbow, were introduced to the lakes and rivers around Yellowstone Park with a fish management program that planted over 310 million species from 1881-1995 (NPS, n.d.). There was no monitoring at the time to determine how the non-native fish would react to native fish or if they were compatible with each other. Because of the introduction of nonnative species, specifically lake trout, native Yellowstone cutthroat trout have …show more content…
They knew there would be no way to completely eradicate lake trout, but if no steps were taken for reducing the lake trout, it was estimated that cutthroat could be eliminated by up to 70% in 100 years (Duncan, Murphy, & Zale, 2009). They started to look at measures which could be taken for controlling the population. At a workshop in 1995, scientists determined that the use of gill netting as a method of gathering information that was needed for determining effective management in reducing lake trout population structure (Duncan, Murphy, & Zale, 2009). With gill netting, they could monitor how many lake trout was reproducing, what their diet consisted of and their habitat structure. Gill netting also provided a way of reducing the population, because when a lake trout was harvested they were killed instead of being released back into the lake. Gill netting has been the proven method for harvesting lake trout over 20 years (Ruzycki, Beauchamp, & Yule,