Leaky barriers could launch carp invasion

Looming over the Great Lakes is the threat of an invasion: Asian carp have colonized nearby rivers, and these voracious fish are now practically at the lakes’ doorstep. Electric barriers are keeping most of the carp out for now, but a few have already been found in Lakes Michigan and Erie.

While some people have argued that hundreds of carp would need to infiltrate the lakes to establish a population, a new study suggests otherwise. Fewer than a couple dozen adventurous fish could be enough to launch a successful invasion, the authors predict. If the invasive carp do take over the lakes, they could harm native fish populations.

The researchers ran computer models of Asian carp population growth, including processes such as spawning and maturation. If a small group of fish — say, 20 or less — reach the lakes, the likelihood of establishment is more than 75 percent under certain conditions, the authors predict. “[T]he most hazardous containment breach scenario is if barriers are continually leaky, and a small number of fish are introduced into the lake basin each year,” they write in Biological Invasions. Roberta Kwok | 17 September 2013

Source: Cuddington, K., W.J.S. Currie, and M.A. Koops. 2013. Could an Asian carp population establish in the Great Lakes from a small introduction? Biological Invasions doi: 10.1007/s10530-013-0547-3.

Image © Doug Lemke | Shutterstock