Martin Lake South Inlet Carp Barrier

This project will protect and improve aquatic habitat through installation of a strategically placed carp barrier, with benefits to connected lakes including Martin, Typo, Island, and Linwood. It is part of a network of four planned carp barriers. Funding for the other three is sought through a traditional DNR CPL grant application. The two applications should be considered a linked package. The carp barrier network will: (a) Prevent seasonal carp migration between favored spawning areas (Typo Lake and tributary creeks) and overwintering areas (Martin Lake), thereby reducing their population. (b) Make commercial carp harvests more effective by preventing escape to surrounding waterbodies and recolonization after harvest. Carp have significant impacts on these lakes by degrading aquatic habitat, replacing game fish biomass and reducing water quality. Martin and Typo Lakes are most strongly impacted and largely devoid of aquatic vegetation. Martin, Typo and Linwood Lakes are all impaired for excess nutrients. Their TMDL plans* cite managing carp as important to lake restoration. Downstream waterbodies including the Sunrise River and St. Croix River are degraded and high priorities. The one barrier requested in this application is located between Martin and Island Lakes, and will prevent carp movement between the two. While carp do not commonly travel this route now, they may do so when other travel routes are blocked by barriers. In this way, this barrier is important to the overall management approach. An ideal carp barrier location exists: a six foot diameter road crossing culvert in the stream connecting Island to Martin Lake. This constriction point assures a reliable barrier. It is within 50 feet of the largest carp source (Martin Lake) and affords protection to the greatest possible upstream area.