Lake Management Planning (LMP) Targets Carp Removal

The LMP Team which includes representatives from 10 local, state and federal organizations has identified the restoration of the Highway K Estuary as a top priority project in 2017. The K Estuary is located on the south side of County Highway K bridge just east of Highway 73. The 200+ acre K Estuary is an extremely valuable shallow water filtering system feeding Big Green Lake. Three of Big Green Lake’s seven tributaries–Wurchs, Spring and Roy Creeks—flow into the K Estuary before their tributary water ultimately makes its way into our lake.

We want our property owners to understand the connection between this project and the “Carp Die-Off” from last summer. In order to restore the K Estuary to its native state (revegetation of this waterbody with emergent and submergent aquatic plants along with native game fish and wildlife), the major hurdle in this restoration project requires us to begin by removing the carp from this waterbody. Carp removal will allow us to revegetate the K Estuary and recapture the valuable water quality filtering benefits of a restored shallow water system. Once this Estuary is revegetated, the restoration won’t last unless we continue to maintain a low population of carp moving forward.

The carp barrier structure—built by the LMP Team on the South side of the K Bridge—is needed to keep carp from moving into the K Estuary from the lake in order to spawn. The carp overwinter in the lake because the main lake becomes more suitable to these nuisance fish as water temperatures turn much colder during the winter months. As water temperatures warm in the spring, carp migrate back to the shallow water systems to spawn because these shallow water systems warm up much faster than the main lake. Furthermore, the water depths (2 feet) and features (muddy and turbid) of the shallow water systems like K Estuary are much more conducive to successful carp spawning, and therefore, create ideal conditions for growing our overall carp populations in the main lake and Estuaries (Silver Creek and County K).

There is strong evidence to support our K bridge carp barrier caused the “Carp Die-Off” from last summer. We tested multiple carp and confirmed that the dying carp showed signs of great stress and physical deterioration, both of these conditions are consistent with fish confronted by a structure such as the carp barrier. The dying carp displayed the characteristics of fish trapped under a bridge for several weeks trying to get back into a desirable spawning area. The carp tested showed no signs of any type of virus, disease or bacterial problems.

Avoiding A Carp Die-Off IN 2017
In order to avoid the carp problems of last summer, we are taking several proactive steps to eliminate most, if not all, of the dead floating carp problems from last summer. The proactive steps outlined below will make carp removal invisible to our property owners and the general public:
• A new and improved carp commercial fishing contractor has been hired to aggressively harvest the carp from under the K bridge beginning in April and continuing throughout the summer for as long as carp continue to show up at the K bridge
• The GLSD will be much more proactive and aggressive in monitoring the carp die-off as well as making daily trips around the lake during the die-off period (early to mid-June)
• Depending on die-off conditions, we are putting backup plans in place to enlist more groups and volunteers to assist in the dead carp collection if needed
• It’s important for property owners to understand that there may be short-term negative consequences from a carp die-off; however, the long-term consequences to
our lake greatly outweigh the short-term problems. Carp are an invasive species and are not good for our lake. Less carp equate to an improved lake in the short-term and long-term. Good science strongly supports removing carp from our main lake and
connected Estuaries.