Species and Origin: The common carp is a large omnivorous fish. They have large scales, a long dorsal fin base, and two pairs of long barbels (whiskers) in its upper jaw. Native to Europe and Asia, it was intentionally introduced into Midwest waters as a game fish in the 1880s.
(Be aware of a native look-a-like: the native fish bigmouth buffalo looks like a carp without barbells)

Impacts:

• Common carp are one of the most damaging aquatic invasive species due to its wide distribution and severe impacts in shallow lakes and wetlands
• Their feeding disrupts shallowly rooted plants muddying the water
• They release phosphorus that increases algae abundance
• Carp induced declines in water quality causes declines of aquatic plants needed by waterfowl and fish

Status: They are established in 48 states. They are distributed in hundreds of waters in the southern two-thirds, and a few waters in the northern third of Minnesota. See US map.

Means of spread: The incidental inclusion and later release of live bait spreads common carp.

Plan

In 2009, the MCWD Board of Managers directed water quality department staff to create a work plan for a carp removal and research program. Water quality staff worked closely with the scientists and researchers from University of Minnesota to develop a carp removal and research program for selected MCWD Lakes. After further discussion and review, MCWD identified Pierson Lake and Lake Wasserman for the first round of carp removal. 

Feasibility

Annual budget for the Carp Removal and Research Program is $40,000.

Design

The MCWD took two typical approaches to carp removal: 

Ice Seining Method:

The commercial fishermen drill holes in the ice and use fish finding sonar to locate the school of carp. Then, a large hole is sawed in ice and a net is threaded under the ice and set into position using remote controlled submarines going in opposite directions. Holes are drilled through the ice approximately every 100 yards. The lead line is snagged at each hole and a winch is used to pull the net to that point. A large hole is opened at the far shoreline where the submarines meet. Winches are used to pull the two ends of the seine up through the ice. The game fish are removed from the seine and released back into the lake. The carp are kept in a contained area of the lake until the following day. Fishermen bring in their large trucks to sort, measure and weigh the carp. The live carp are then transported for resale to fish markets.

Open Water Seining Method:

The fishermen use fish-finding sonar to locate the school of carp throughout the lake. A seine with floats attached to the top of the net and weights attached to the bottom of the net is trailed behind the boat, encircling the fish. The rope is pulled using a mechanical pulley through the rings at the bottom of the seine preventing the fish from escaping the net. The fish are placed in a contained area in the lake until the following day when hauling trucks are brought in to sort, measure and weigh the carp. The live carp are then transported for resale to fish markets.

Narrative

• The Minnesota Department of Natural Resources conducted a Piersons Lake fish survey in 2007
• Blue Water Science conducted a fish survey for Lake Wassermann in October 2010
• In November 2010, the MCWD Board approved a plan for Lake Wassermann and Piersons Lake to remove and manage the carp population in an effort to reduce internal phosphorus loading
• Staff communicated with lake associations and cities and lakeshore residents to provided update on the project
• Ice seining of the carp took place mid February 2011on Lake Wassermann
• Carp barriers were installed on Piersons Lake outlet, Marsh Lake outlet, and Lake Wassermann outlet in April 2011 to prevent migration of carp to their breeding areas
• Open water seining of the carp took place in mid May 2011 on Lake Wassermann

Summary

On November 18, 2010, the MCWD Board of Managers authorized water quality staff to implement the carp removal and research program and construction of carp barriers at the outlets of Piersons Lake, Lake Wassermann, and Marsh Lake. The removal and management of the carp's spawning habits is an effort to help improve the water quality in Pierson Lake and Lake Wassermann by reducing the internal loading of phosphorus, as well as improve the water clarity. Carp can impact a water body by increasing turbidity, releasing nutrients in the sediment, and destroying aquatic vegetation and aquatic habitats during feeding activities. 

2011

Removal of the carp on Lake Wassermann was attempted by licensed fishermen in February 2011. The attempt failed due to the nets getting caught up in debris on the bottom of the lake when they were being pulled, allowing the carp to escape under the net. It was again attempted on Lake Wassermann in May 2011. While fishermen caught about 1,000 pounds of carp, nets continued to get caught on the bottom of the lake and several carp managed to escape. 

In April 2011, carp barriers were installed at the outlets of Piersons Lake, Wassermann Lake, and Marsh Lake. The barriers were used to keep the carp from entering into their spawning area where they have greater reproductive success. Marsh Lake is a shallow lake located between Piersons and Wassermann that tends to have a high percentage of fish die during the winter. The fish kill allows the carp to have less predation on their eggs. By preventing the carp migration to the breeding area, it forces the fish to spawn in the deeper lakes allowing a higher percent of the eggs to be eaten by pan fish.

Starting in May, the Area Partnership for Piersons Lake Enhancement (APPLE) trapped and removed approximately 36,000 pounds of carp from the Piersons Lake outlet. Vegetation surveys also were completed in both Piersons Lake and Lake Wassermann to provide information on plant diversity and density.

2012

MCWD staff are currently working on a partnership with Dr. Peter Sorensen from the University of Minnesota's Fishery department on a three year study to assess movement, abundance, and age structure of adult common carp in the Six Mile Creek as part of a comprehensive diagnostic study to better understand water quality issues and concerns throughout the Six Mile Creek subwatershed.  This information will provide basic information on carp in this system and allow for recommendations for possible control, as well as, provide further guidance for identifying and implementing future projects and initiative to improve the water quality along Six Mile Creek.

The prevention of carp migration with the use of fish barriers and removal of carp from the lakes has been placed on hold at this time.  The partnership between MCWD and Dr. Sorensen and his research team is currently pending with hopes of beginning a study soon.