MAISRC researcher leads a collaborative team to explain the enigma of common carp invasions
Common carp are one of the world’s most invasive fish and have long been a problematic presence in many Minnesota lakes. But the destructive fish – which search for food on the lake floor, disturbing sediment and uprooting vegetation – have never become abundant in some parts of the world, such as the Boundary Waters, while becoming superabundant in others.
This enigma inspired MAISRC researchers to study why carp become so invasive in some ecoregions but not in others, thereby helping to explain their invasion patterns in Minnesota and beyond. The results of the study, led by MAISRC researcher Dr. Przemek Bajer, were recently published in Diversity and Distributions, a leading journal of invasion biology.
Researchers studied over 550 lakes throughout different ecoregions in the Midwest, looking at factors such as lake clarity and productivity, different species of native predatory fish, and abundance of adult carp. Ultimately, researchers found that two simple ecological filters – lake productivity and abundance of bluegills – can explain the success of carp. Carp can become invasive only 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 cannot survive the critical developmental period.
These ecological filters may help explain the different patterns of carp invasions among ecoregions – like the productive lakes of the Great Plains or Temperate Forest covering south-central Minnesota where carp are common, versus the oligotrophic Northern Forest of the Boundary Waters lakes, which are nearly void of carp.
By studying introduced species across different regions where they are or are not able to become invasive, researchers can better determine processes that facilitate invasions and also those that curb it.
“Before we can figure out how to control an invasive species like common carp, we need to understand what allows it to become so invasive in some regions and what’s holding them back elsewhere” said Dr. Bajer. “If we only look in areas where they are very successful, we may never find their weaknesses.”
Read the full paper, “Across-ecoregion analysis suggests a hierarchy of ecological filters that regulate recruitment of a globally invasive fish,” online here.
This collaborative work included other MAISRC researchers, the Minnesota DNR, and carp biologists from Iowa and Nebraska. Bajer’s research was funded by the Riley Purgatory Bluff Creek Watershed District and by Ramsey Washington Metro Watershed District; lake survey data and GIS resources were provided by Minnesota Department of Natural Resources, South Dakota Game, Fish and Parks, and Nebraska Game and Parks.