Long Lake Waters Association

Carp Removal in Long Lake Creek Watershed

Background:

One of the key drivers of the poor water quality in the Long Lake Creek Watershed is the overabundance of invasive carp. These large, aggressive, non-native fish drive out native species like walleye and bluegill, and destroy the habitat for beneficial aquatic plants. They stir up phosphorous that decreases water clarity and promotes algae growth. They move throughout the entire seven lakes and many streams of the Long Lake Creek Watershed (fun fact: carp can move in < 2 inches of water!) and damage the ecosystem wherever they go.

2019 and 2020:

Since 2019, Long Lake Waters Association has participated in a partnership with the cities of Long Lake and Medina to remove carp from Long Lake. This process involved electrofishing for carp, Radio tagging, RFID tagging, volume estimates, aging, tracking, and unsuccessful attempts at both summer and winter removals in 2019 and 2020. Specifically, in 2019, watershed district personnel tagged ~280 carp with micro tags in various lakes in the watershed (131 in Long, 97 in Tanager, 48 in Wolsfeld).

2021 and 2022:

However, in 2021, box-netting the carp proved successful, and that approach has proven successful in 2022 as well.

Carp Solutions removed a total of 1,107 adult carp in the summer of 2021.

In summer of 2022, Carp Solutions baited five box nets and had four hauls with excellent results. 1,056 additional adult carp were removed, with each fish averaging around ten pounds, and it appears these carp did not migrate from connecting lakes.

Overall, 2,240 carp were removed over the last two years, which is approximately 42% of the entire population of carp inhabiting Long Lake.

We are happy to report that as a result the carp levels are reaching acceptable thresholds within Long Lake.

Detailed Findings:

Among the carp captured in Long Lake in 2022 and 2021, 46 were tagged. All of those carp were tagged in Long lake, except for 2, which were tagged in Tanager. This suggests that not many carp move between Tanager, Long and Wolsfeld. Harvested carp were large (~ 9 lbs average), which suggests that production of young carp in the system has been low in the last decade or so.

Carp solutions estimates about 3,000 carp remain in Long Lake indicating the population is steady, and currently there is no evidence of juvenile carp in the lake. The recommended management goal for carp populations is 100kg/ha, or 90lbs/acre, which means fewer carp will disturb the lake bottom and therefore have minimal impact on the lake ecosystems.

Next Steps:

Approximately ~ 220 more carp should be removed in the future to suppress the population to a level that should not cause any significant impact on the lake, but the current carp biomass is already relatively low.

We are grateful for the support from the cities of Long Lake and Medina, to Dr. Przemek Bajer and Carp Solutions, to the Long Lake residents who provided lake access and to all supporters and donors that contributed to the success of the Long Lake carp project.

You can help!

Any size donation makes a difference – Please consider supporting Long Lake Waters Association in our quest to improve water quality!

We are on a mission to protect and enhance the water quality within the Long Lake Watershed!

Learn More:

Learn More at Lakeshore Weekly News!

About the Long Lake Creek Watershed:

The Long Lake Creek Watershed covers over 7,619 acres, and includes seven lakes (School, Holy Name, Mooney, Wolsfeld, Dickey's, Long Lake and Tanager on Lake Minnetonka), as well as all the surrounding streams and wetlands. It encompasses three cities (Medina, Orono and Long Lake) and over 6,000 households.

Long Lake Creek Watershed is also the headwater for Lake Minnetonka and Minnehaha Creek, which in turn flows into the Mississippi River.

Many Minnesota residents and visitors enjoy these lakes, streams and wetlands for fishing, boating, birding, swimming and hiking, but many don’t know that the Long Lake Creek watershed is seriously degraded, and its problems are impacting the downstream water bodies.

Seven Lakes * Three Cities * One Watershed

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