Something is Fishy:

December 6, 2019

Why Fish Removal Can be Necessary and How it Works

By Joseph J. Berg,
Aquatic Field Biologist, Fisheries Specialist

Fish treatments/removals are a part of common management practices for fisheries throughout Wisconsin and the United States. You may ask why “killing” fish is necessary. In nearly every case, the targeted species found their way into the pond unintentionally and are causing problems for the goals or uses for a particular waterbody. For example: invasive or aggressive species can out-compete or eradicate desirable gamefish species which does not allow for a healthy fishery. Fish treatments/removals can also be performed to eradicate problematic species that can cause damage to pond structures. For example: A recent treatment was performed on a sanitary lagoon in Wisconsin to eradicate carp that were causing non-compliance with discharge regulations.

To complete a fish treatment and removal, a number of necessary steps must be completed. First, you should consult with a professional to determine if a treatment is right for your lake or pond. Waterbodies are not all suited for this type of treatment. In addition, most problems with fish populations can be controlled by other fishery management or stocking strategies. Consider other methods prior to a treatment. If treatment is the right option for you, we work with clients to gain state approval with fisheries biologists from the state DNR and proper permitting. Once all necessary approvals and documentation is completed, we schedule a treatment for your waterbody. Our staff utilizes metered injection of a water and product mixture to distribute throughout the pond. Once injected, the product acts fast by blocking oxygen pathways utilized by fish. Removals can often be completed after a handful of minutes (especially in warm water) to a couple days (when water temperatures are cold). If a treatment is performed, most waterbodies should be restocked in the coming months with desirable species to achieve desired results and to prevent unwanted introduction of other species in a “new” environment. Careful planning must be done prior to treatment same problem being treated or to achieve the desired goals.

Other Notes & Considerations:

For the vast majority of lakes and/or ponds, adjustments can be made to a stocking plan to create a more ideal and balanced ecosystem and fishery. We occasionally recommend fish treatments/removals but consider other methods prior. However, sometimes they are the most practical solution to accomplish goals for a waterbody or fishery. If you think a treatment and removal may be right for your waterbody, please do not hesitate to contact us to discuss with a professional if it is a potential solution. WLPR offers treatment services in addition to planning and completion of your fish (re)stocking plan to make your fishery the best it can be!