Wisconsin Invasive Fish Rule

Under the previous rule, anglers who caught invasive species like the round goby had a daily bag limit of zero and were only permitted to kill and possess one fish for the purpose of transporting it to a Department of Natural Resources (DNR) office for identification. The new regulation marks a significant departure from this, now allowing for the unlimited harvest of these fish. This change specifically targets species classified as "detrimental fish" under Wisconsin's administrative code. This category includes all fish species that are not native to the state's waters. The rule aims to empower anglers to actively participate in controlling the populations of these harmful non-native species. The list of invasive fish threatening Wisconsin waters is extensive and includes well-known species such as the round goby, sea lamprey, and multiple types of Asian carp (bighead, silver, black, and grass carp). These species are often introduced through channels like the ballast water of oceangoing ships. The ecological damage caused by these invaders is severe. Round gobies, for instance, are aggressive bottom-dwellers known for eating the eggs of native sportfish, while Asian carp consume vast quantities of plankton, disrupting the foundational food source for many native fish. This competition and predation can lead to a decline in native species and a reduction in overall biodiversity. Economically, the impact is staggering. Invasive species threaten the Great Lakes' sport and commercial fishing industry. The costs associated with managing these species and the damage they cause to industries like power generation and municipal water plants run into billions of dollars annually. The rule change is part of a broader strategy for managing invasive species outlined in chapters of the state's administrative code, including NR 20 and NR 40. While the unlimited-kill rule is a new tool, long-standing regulations that prohibit the transport of any live invasive species remain firmly in effect to prevent their further spread. Anglers choosing to remove detrimental fish must kill them immediately upon capture. The DNR specifies that the fish must be dispatched in a way that ensures they cannot be revived, such as by evisceration or decapitation, before being transported. This new regulation reflects a shift towards more direct control measures by engaging the public. The DNR aims to align public action with management goals, turning anglers into a key component of tracking and controlling the spread of these detrimental fish populations throughout the state's waterways.