Asian carp eaten by bass, but some carp are more vulnerable than others to native species
Silver and bighead carp both pose a risk to the Great Lakes, but new research suggests that the “flying” silver carp may be better at avoiding native predators.
Although they are often lumped together as “Asian carp” the bighead carp and silver carp are two distinct species. Bighead carp typically grow larger, are less abundant, feed more exclusively on zooplankton, and do not jump. Eric Sanft, a graduate student working under Dr. David Wahl with Illinois Natural History Survey and the University of Illinois, tested the vulnerability of both species to largemouth bass. Results were presented at the 75th annual Midwest Fish & Wildlife Conference last week in Indianapolis, Indiana.
Silver and bighead carp were placed in experimental pools along with native gizzard shad, bluegill, and golden shiner. Largemouth bass were also placed in the pools to determine which prey fish were most vulnerable. The bass ate more bighead carp than any other species including silver carp. This may help to explain why silver carp have been more successful at colonizing Midwest rivers. Their young appear to be a bit more “street-smart” than young bighead carp.
Although new research is confirming that native fish can and do consume Asian carp, this does not mean that all is well. In the LaGrange Reach of the Illinois River at least seven native fish are preying on Asian carp. Even so, this reach has one of the highest densities of silver carp recorded anywhere in the world. Native plankton-eating fish like gizzard shad and bigmouth buffalo have declined and the long-term effects on gamefish are still uncertain.
In the Great Lakes we already know that native fish are adapting to non-native prey items like quagga mussels and round gobies. We also know that predation has not been enough to eliminate these species or prevent their negative effects. The same is likely true for Asian carp.