Grass carp in Lake Erie system 'ominous' sign that more damaging species could invade Great Lakes

In July, the Obama administration unveiled a $50 million plan to keep invasive silver and bighead carp out of the Great Lakes, where they pose a threat to native species and the fishing and tourism industry. This week, scientists announced that another type of Asian carp have begun to reproduce in the Lake Erie watershed, which The Associated Press called "an ominous development in the struggle."

Researchers with the U.S. Geological Survey and Bowling Green State University analyzed four small grass carp caught last year in Ohio's Sandusky River, which runs into Lake Erie, and determined that they had spent their entire lives in the water, "were not introduced through means such as stocking" and "could become spawning adults."

The grass carp "are less worrisome because they eat larger plants instead of plankton and don't compete with native species, although they could harm valuable wetland vegetation where some fish spawn," AP reports. "Of greatest concern in the Great Lakes region are bighead and silver carp, prolific breeders that gobble huge amounts of plankton — tiny plants and animals that are vital to aquatic food chains. Scientists say if they gain a foothold in the lakes, they could spread widely and destabilize a fishing industry valued at $7 billion." (Read more)

Grass carp, which are used to keep ponds clean, cannot be legally sold unless they are sterile. There are several ways fertile grass carp could have been introduced into the Sandusky River, but the only one that is really worrisome when it comes to silver and bighead carp is that an angler who bought minnows for bait in the Mississippi-Ohio River system got some carp minnows (which look like minnows of other fish) and released them into the river or Lake Erie, Duane Chapman, a USGS biologist on the project, told The Rural Blog. “These findings are significant because they confirm recent USGS research indicating that shorter rivers, like the Sandusky, are potential spawning sites for grass carp and other Asian carps as well,” Chapman told Matt Markey, outdoors editor of The Toledo Blade. (Read more) Read more on Asian carp here, here, here, and here.