Recently whirling disease has spread to the waters of Yellowstone Lake, this comes to a huge blow to the protection of one of the greatest cutthroat populations in the world, which is already threatened by the illegal introduction lake trout. According to the national park service (2007) 11 of 41 yellowstone cutthroat sampled at mouth of Clear Creek in Yellowstone Lake tested positive for the disease. This disease is caused by a microscopic parasite and attacks the cartilage of the infected fish. While the diseases may not directly kill these fish, it affects their swimming ability and may lead to infected fish starving to death. Unfortunately for the cutthroat, the disease does not seem to affect lake trout.
Rainbow trout in Oregon with whirling disease: note the blackened tails (Photo Credits: Stephen Atkinson - Montana University System Water Center)
Another threat to a number of popular fisheries, such as the Madison River, Firehole River and South Fork of the Snake River is the New Zealand Mud Snail. This invasive snail compromises the food web by out competing aquatic insects and thus leads to declines in fish populations. Today the Mud Snail is found in fisheries across the western United States, in Idaho, Montana, Wyoming, Oregon and California and is having impacts on populations of Pacific salmon, cutthroat, redband, rainbow and bull trout.
These are just a couple of the many invasive species that are having impacts on our native trout and cold water fisheries in general, and what do they have in common?? They can be spread by anglers not cleaning their gear before traveling between fisheries. This may include boats, rods, reels, waders and boots. These are not the only invasive species that are spread this way either. Milfoil, zebra muscles and didymo are a few others that are spread this way.
In order to prevent the further spread of these invaders, it is up to each and every angler to be responsible and inspect, clean and dry their gear before traveling between fisheries. This is as simple as looking for anything attached to any of your gear, removing it and washing everything off before traveling to another stream or lake. To help remind anglers of the importance of these steps, the folks at the Center for Aquatic Nuisance Species have developed the Clean Angling Pledge, which states that you will inspect, clean and dry your gear before traveling to another fishery.
According to Bill Wiltshire the director of the Center for Aquatic Nuisance Species:
The Pledge is being widely supported by organizations, agencies and the fishing industry. Trout Unlimited and the Federation of Fly Fishers both encourage their members to take the pledge. Montana Fish, Wildlife & Parks has adopted the pledge as their primary means of getting individual anglers involved. We are working with Simms, Patagonia, Corkers, Dan Baileys and other wader manufacturers to incorporate the pledge into their marketing and communication efforts and many others in the fly fishing industry are promoting the pledge to their employees and customers.