by Ward Mullens, Published March 30, 2010
YPSILANTI - In a March 22 ruling, the United States Supreme Court blocked a second request for an injunction ordering Chicago to close two navigational locks in an effort to keep Asian carp from invading the Great Lakes.
“The worst case is that the Asian carp establishes a population in the Great Lakes, like it did in the Illinois River,” said Ulrich Reinhardt, professor of biology at Eastern Michigan University. “If it does, it would displace many native species and we would lose our recreational fisheries.”
It is estimated that fishing and tourism revenues in the Great Lakes generates nearly $7 billion annually.
Although Reinhardt is not optimistic about the Asian carp situation, he is fighting on the front lines against another invasive species – the sea lamprey.
Lamprey are eel-like parasitic fish that attack native fish such as lake trout and white fish, and feed on their blood and guts. A single sea lamprey can kill 50 pounds of fish in less than two years. They have been a threat to the Great Lakes since the 1950s.
An estimated $15-$20 million dollars a year is spent to control the sea lamprey population.
Various control measures have been used, including dumping a poison in waterways to kill young sea lamprey in streams. The latest measure to be tested now involves dumping a pheromone in waterways that attracts the adult fish to allow easier catching.
“The poison impacts native fish populations such as sturgeon as well,” said Reinhardt, who began working on the sea lamprey situation five years ago.
Reinhardt’s strategy involves using the sea lamprey’s poor swimming skills and gravity against it. He is designing ramps that would block sea lamprey migration routes in rivers without hindering migration of native fish species.
The ramps would look like damns but would have a passage on one end that would allow native fish to swim up the ramp.
“Sea lamprey are not strong swimmers,” Reinhardt said.
Thus far in lab experiments, Reinhardt said that native fish such as white suckers, creek chub and golden shiners were able to swim up the ramps.
Reinhardt won an initial grant from the Great Lakes Fisheries Commission to develop his strategy and is contention for a larger grant that would implement several test ramps in area waterways.
While Reinhardt and others are working to keep invasive species from spreading and potentially ruining the Great Lakes, other threats are looming.
“The Quagga mussel is replacing the Zebra muscle,” Reinhardt said. “It’s flying under the radar.”
Reinhardt said that some of the invasive species threats could be stopped by implementing changes in the way large ships use ballast water.
Reinhardt said that ships that draw ballast water from fresh water in other countries could help eliminate many invasive species by dumping the fresh water ballast in the ocean and then drawing saltwater before entering freshwater again.
“Precaution is not popular if it costs money,” Reinhardt said.