common carp

Common carp are one of the world’s most widely introduced and invasive species of fish. Currently, they dominate the fish biomass of many shallow lakes, rivers, and wetlands in North America and around the world, including many lakes in central and southern Minnesota. Carp degrade water quality and destroy waterfowl habitat by rooting in the lake bottom while searching for food.

Current MAISRC research on common carp focuses on: 1) developing toxin-delivery systems and testing the limits of common carp biocontrol in hypereutrophic lakes; 2) determining abundance, seasonal movements, and recruitment patterns in Six Mile Creek subwatershed in order to develop carp control strategies; 3) determining the seasonal distribution and 24-hour movement patterns of common carp in an attempt to restore ecological balance to a Rice Creek watershed; and 4) developing eDNA and microbial techniques for detection of multiple carp species. Click here to download a factsheet about common carp.


About Common carp

Life cycle

Common carp mature at the length of ~ 30 cm when they are 2-3 years old.  Females can carry up to 3 million eggs. Once mature, adults of both sexes migrate into shallow wetlands to spawn in the spring. Once released by females, the eggs are immediately fertilized and stick to submerged vegetation. The eggs develop and hatch within a week. Each female can produce several hundreds of yearlings and carp can quickly become superabundant. However, this occurs only in habitats that lack native predators, such as marshes that winterkill (when fish die in winter due to a lack of oxygen). In most lakes in Minnesota, young carp survive poorly because abundant panfish populations can decimate carp eggs and larvae. Marshes that winterkill are key nursery habitats for carp in Minnesota.

In addition to panfish controlling carp eggs and larvae, there are two other factors in carp’s life cycle that can be targeted for control. The first is that adult carp aggregate together (shoal) under the ice, during which time they can be located using telemetry and removed with seine nets. The second is their migrations from lakes to marshes to spawn, which can be blocked or targeted for removal. 

What they affect

Common carp degrade water quality and destroy habitat for waterfowl, fish and amphibians. They are voracious feeders that forage primarily on plant seeds and insect larvae that live in lake sediments. While searching for food, carp burrow into lake sediments and in the process they uproot aquatic vegetation, increasing water turbidity and releasing large quantities of sediment-bound nutrients, which stimulate algal blooms. It is estimated that over 70% of lakes in southern Minnesota have lost their plant cover and suffer from excessive algal blooms due to carp’s foraging activity. Tens of thousands of hectares of waterfowl habitat have been devastated by common carp.

Where they're found carp

Common carp have large populations in North America, Australia, and New Zealand. They are native to Eastern Europe and Asia. Currently, common carp are established in 48 states in the U.S.

In Minnesota, they have become superabundant in some lakes, primarily in central and southern Minnesota, but have not become established in others – for example the Boundary Waters.  Research at the Minnesota Aquatic Invasive Species Research Center has established that two simple ecological filters – lake productivity and abundance of bluegills – control the success of carp.

Carp become invasive in regions with productive lakes that also have low abundance of bluegills, which eat carp eggs and larvae. In all other lakes, those that are clear and oligotrophic or which have high densities of bluegills, carp are not invasive because their eggs and larvae do not appear to be able to survive the critical developmental period.

How they spread

Common carp are renowned for their fast growth, large size, high fecundity, and physiological resiliency, all of which contribute to their large numbers in many Minnesota lakes. They spawn in shallow lakes and wetlands, which enhances their ability to spread. They also have a natural tendency to move through interconnected rivers. They can also be spread through the accidental inclusion and later release of live bait. 

What they look like

Common carp can live over sixty years and can reach a length of 1 meter. They resemble some native fish, such as the bigmouth buffalo, but can be distinguished by two sets of small whiskers near the mouth. Carp are golden-brown and have large scales.



common carp



common carp

Common carp research at MAISRC

Researchers carp

Completed efforts

  • Determined that the success of carp populations can be explained by a combination of lake productivity and abundance of native predators (Bajer et al. 2015a)
  • Identified several weaknesses in carp's life cycle that can be targeted for control (Bajer and Sorensen 2010, Bajer et al. 2012)
  • Demonstrated that native predators, such as bluegills, can control carp reproduction in most lakes in Minnesota by consuming carp eggs and larvae (Bajer et al. 2012, Bajer et al. 2015a)
  • Demonstrated that up to 90% of adult carp can be removed from lake using winter seining that targets carp aggregations (Bajer et al. 2010)
  • Demonstrated that carp can be trained to aggregate in specific areas of lakes using food (Bajer et al. 2011).
  • Determined a biomass threshold at which carp become damaging to lake ecosystems, which allows for setting clear management goals (Bajer and Sorensen 2015)
  • Developed rapid-assessment methods to estimate carp biomass in lakes using boat electrofishing (Bajer and Sorensen 2012).
  • Determined how the partial migrations of carp lead to their success (Bajer et al. 2015b)
  • Developed mechanistic model that explains the success of carp in complex systems of lakes and marshes which can now  be used to affect carp control (Bajer et al. 2015b)
  • Implemented a successful control plan in the Riley Chain of Lakes and the Phalen Chain of Lakes; including seining fish once they are aggregated, using bluegill sunfish to consume carp eggs and larvae, and using aeration to prevent winterkills.
  • Used common carp as an assay to optimize techniques to capture and extract environmental DNA for detection and quantification of fish (Eichmiller, Miller, and Sorensen 2015)
  • Established that eDNA concentrations were very high where common carp densities were high, but dropped precipitously in time and space, suggesting eDNA decays very quickly (Eichmiller, Sorensen, and Bajer 2014)
  • Discovered that common carp regenerate their reproductive organs approximately a year following gonadectomy – an unexpected finding following efforts to develop the Judas fish technique for Asian carp

Current efforts

  • Developing selective toxin delivery systems to enable control of common carp populations in especially challenging ecosystems where biological control is weak (winterkill-prone prairie lakes)
  • Testing the limits of common carp  biocontrol to determine if biocontrol works in hypereutrophic lakes
  • Determining abundance, seasonal movements, and recruitment patterns in Six Mile Creek subwatershed in order to develop carp control strategies
  • Determining the seasonal distribution and 24-hour movement patterns of common carp in an attempt to restore ecological balance to a Rice Creek watershed
  • Developing eDNA and microbial techniques for detection of multiple carp species

Projects

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