The Northern Pike

Written by Spencer Anderson, ESLLC 2017-2018

The Northern Pike is the most notorious invasive fish in Colorado. It’s a freshwater predator from Britain and Ireland. The introduction of this species to North America happened some time in the 1950s, and since then they have been migrating west. They can be found in a majority of U.S. states and most provinces of Canada. Sport fishing for Northern Pikes has become very popular in the U.S. since the introduction of the species because of its enormous size. Fisherman used to take juvenile Pikes from infested streams and lakes and drop them into secluded ponds. The Pikes would breed and grow in the new waters, and the fisherman could catch a 40 pound Pike easily in just a few years. This practice has been outlawed, but it has created irreversible damage.

Pikes are always at the top of their food chains and can reach up to 40 pounds in size. They’re aggressive, mean, belligerent, and territorial fish. They are ambush hunters, meaning they will lie on the bottom and wait for their prey to swim past them. This makes them deadly for native fish like salmon and trout that must continuously swim in order to survive, and this makes the Pike unreachable from predators like birds and bears. They eat everything from ducklings to fully grown salmon. One or two Northern Pikes in a lake won’t destroy the ecosystem, but once the fish manages to lay eggs, there is no stopping the damage. Northern Pike hatch a few weeks before most native fish. Once they reach a few centimeters in length, they go after trout and salmon fingerlings (baby fish). Because of their head start, a few juvenile Northern Pikes can kill an entire generation of native fish. Once the Pikes have grown bigger, they hunt larger native fish. In a few years the only thing left in the lake is the Pikes. The larger Pikes die off as their source of food disappears, and soon stunted Pikes are all that remains. When the U.S. Fish and Wildlife Service tries to restock the lake with the native fish, the same cycle happens again. So how do we get rid of the Pike?

Many states have different answers to this question. In California, if you catch a Northern Pike you are required to cut its head off. In Colorado’s Green Mountain Reservoir, game officials will pay you twenty dollars for each Pike you catch. In Alaska, transporting a live Pike or Pike eggs can earn you a 10,000 dollar fine. Game wardens in Alaska have even tried getting rid of the Pike with nets, but because Northern Pikes like to hang out in the mud those efforts are rarely effective. The only surefire way to kill all the Pikes in a lake is to drain the lake completely or poison the waters.

Poison the waters?!?! I know it sounds like a supervillain’s master plan, but it’s a safe practice if done correctly. Game wardens use a chemical called Rotenone. Rotenone is a naturally occurring compound that has been used as a pesticide since the 1800s. It has been used to kill invasive fish since 1930. Rotenone blocks oxygen from being absorbed by a fish’s gills, and the fish suffocate. In low doses, it has no effect on plants, birds, or mammals. The chemical is broken apart by sunlight in a few days and has an “antidote” that can neutralize the compound. Rotenone has been approved by the EPA for this use, and there have been no illnesses caused by Rotenone in this context. Poisoning waters sounds terrible, but the only things that are killed are the ugly freshwater mud sharks known as Northern Pikes.

Rotenone and other efforts have proven to be effective in many cases, but they cost millions of dollars and years to implement. We must protect our streams, rivers, ponds, and lakes is by educating the public on the dangers of the species. We can also implement and enforce laws that prevent people from spreading the species to new lakes and ponds. However, the best way to help is to show support for Northern Pike management efforts. The main roadblock in stopping this fish is public opinion. When a county hears that their reservoir is going to be drained or that a lake is going to be poisoned, the public outcry usually stops the Fishing and Wildlife Service from implementing the plan. The disapproval is understandable, but by showing support for these issues you help preserve the natural beauty of your country. Pikes are rude dudes. They are no good for the environment, and cast a large shadow on the future of our lakes and streams. Like any environmental issue, if we educate the public and show support for the issue we can make a difference.



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