A Parasitic Infestation is Killing Fish in Larimer County Lakes
A parasitic infestation is currently impacting fish in the Northern Colorado area, particularly at West and Dowdy lakes in Larimer County.
According to Colorado Parks and Wildlife, anchor worms have been detected in these lakes and are causing fish to die.
What happens, is that adult female anchor worms permanently attach to a fish, and when they do so, it results in severe inflammation. The inflamed area then turns into visible and open bleeding sores on the fish, and other negative impacts like stress, secondary infection, osmotic imbalance, and death can occur. In addition, the free swimming immature stages of anchor worms will also take the chance to feed on the gill tissue of fish, which is not only an irritant, but also causes significant damage to their respiratory systems and osmoregulation patterns.
Anchor worms are not new to West and Dowdy Lakes. CPW says the parasite has popped up in these same places before, and cited reasons such as slow-moving water and high densities of fish as some of the factors that can cause infestations.
Since anchor worms have the potential to spread to other bodies of water, CPW wants anglers to be aware of the current situation. It's suggested that anglers who have gone fishing at these two lakes decontaminate their waders and other equipment before throwing their line in at another location.
CPW explains that anglers should look for parasites attached to the body or fins of a fish, and in the gills. The anchor worms can be green, white, or red in color. Although it sounds kind of gross, wildlife officials note that people can still eat the fish after the worms are removed and it's cooked.
So far, anchor worms have been seen on both trout and suckers.
Both Red Feather lakes are stocked stocked annually with both catchable and sub-catchable fish. All remaining stockings at West Lake have been cancelled for the season.
Once the anchor worm population is fully removed, there shouldn't be problems unless it somehow gets reintroduced to the waters.