Researchers successfully install electric fish guidance system to remove carp during spawning migrations
MAISRC researchers installed and tested a low-voltage electric fish guidance system in Rice Creek this month, as part of a larger, first-of-its-kind effort to remove thousands of invasive common carp during their spawning migrations. The barrier was installed now to test how carp react to it, including whether they challenge it and learn from it. An electric barrier is used in this large stream so that water and debris can still flow freely. This project is conducted in partnership with Rice Creek Watershed District and is led by Dr. Przemek Bajer.
This coming spring, about 20,000 carp will migrate from Long Lake through Rice Creek and into shallow marshes near Lino Lakes to spawn. When that occurs, researchers will use this same electric barrier to guide the fish through a chute, toward a trap, and into a technology called the Whooshh System. Whooshh was first developed to move salmon around dams in the western U.S. and is now being adapted for this purpose. (If you missed it at the Showcase, check out a video of Whooshh in action here.) When fish enter the Whooshh chamber, they are pneumatically pushed through a flexible tube and safely and quickly delivered around barriers – or in the case of invasive fish, into a cage for removal. This is the first time this technology has been used for invasive carp removal in the United States.
To make sure the barrier is working as desired, researchers tagged about 100 carp and tracked their movement electronically. They also tied small floating tags to a few of them to monitor their behavior visually – watch a video of this here. They found that nearly all carp followed the guidance system and entered the desired chute in the first 24 hours. No carp were able to swim through the barrier. Unlike other electric barriers, the system used in this study, developed by Procom Systems, uses a very mild electric field to guide the fish rather than to stun them, and is portable so that it can easily be modified to fit specific study sites and deployed within hours.
During their spawning run, carp are extremely determined to reach their destination. This migratory behavior is a unique characteristic that researchers can capitalize on for control. Although there are other options for removing common carp, such as winter seining and drawdowns, those methods are often unreliable or very expensive. This new technique developed by MAISRC researchers is significantly more effective, efficient, and sustainable.
Common carp are one of the world’s most widely introduced and invasive species of fish. They can degrade water quality and destroy waterfowl habitat by rooting in the lake bottom while searching for food. Learn more about common carp here.