New Evidence of Mounting Asian Carp Invasion at Great Lakes

A new series of DNA analyses have revealed the possible beginnings of an invasion of Lake Michigan, with evidence of Asian carp showing up in a pair of Michigan tributaries.

Earlier this month, a single sample of silver carp DNA was identified in over 200 samples taken from lower Kalamazoo River in Allegan County, Michigan. This worries officials, who have never seen the carp's DNA in these waters before. However, it remains unclear where the sample came from.

According to the Michigan Department of Natural Resources (MDNR) and US Fish and Wildlife Service (FWS), genetic material could have simply entered Michigan waters through boats, fishing gear, or even bird droppings. However, if follow-up sampling finds more evidence, they may very much be looking at the beginnings of a long-feared invasion.

"Although not conclusive, this finding heightens our vigilance and sets into motion a specific response," MDNR Director Keith Creagh said in a statement. "We will work with our partner organizations and anglers on next steps to protect the Great Lakes and its tributaries against this significant threat."

The MDNR has already established a line of communication with local anglers, describing what kind of fish to keep a lookout for. Testing of additional samples taken from Kalamazoo River has also begun in the hopes that no more of the DNA is detected.

Worryingly, this isn't the only sample detected. Michigan officials told local media Tuesday that silver carp DNA was also found in Fox River in downtown Green Bay. Like with Kalamazoo, this came from a single sample among 200.

"It's important," Bob Wakeman, aquatic invasive species coordinator for the MDNR, told the Milwaukee - Wisconsin Journal Sentinel. "But we don't want to jump to conclusions that Asian carp are there."

So why all the panic over some fishy water? Invasive Asian carps like the bighead and silver carps have few predators and are voracious eaters, consuming large amounts of plankton - a crucial source for native fish and other aquatic life. Scientists fear that the spread of Asian carp will cause irreparable harm to the Great Lakes' food web.

The FWS estimates the net worth of the Great Lakes fishery is about $7 billion. That and other economic interests dependent on the Great Lakes and their tributaries have prompted a strong political desire to protect these waters from encroaching invasion. Just last month, US and Canadian organizations held a series of field exercises to experiment with strategies to prevent an Asian carp invasion of Lake Erie, which is expected to be the most vulnerable of the Great Lakes.