"An Asian Bighead carp swims in the Great Lakes Invasive Species tank at Chicago's Shedd Aquarium." Image credit:Nancy Stone/ Chicago Tribune.
I hate it when lawyers end up managing shared environmental resources. So, it is with some pleasure that I share this breaking news, from the Chicago Tribune: "The Supreme Court turned back the Asian carp issue today, rejecting a request from Michigan and other Great Lakes states to force Illinois to stop the flow of water from its rivers into Lake Michigan."
Actually, the Trib wrote about this in a confusing way. The
Illinois Chicago River naturally flowed into Lake Michigan until, in the early 1900's, a series of man-made flow control structures were built to prevent storm water and sewerage from the City of Chicago from discharging into the lake and getting into Lake Michigan drinking water intakes. The diversion also provided for barge traffic connecting to the Mississippi River. (Chicago River waters were thus diverted into the Illinois River and on down to the Mississippi, via the Sanitary and Ship canal.) What Michigan wanted in requesting the lock-closing court injunction was to keep river locks permanently closed to impede the migration of Big Head carp toward Lake Michigan - which would eliminate one of the major benefits of the Federal project, as managed by the US Army Corps of Engineers.I'm with the leave 'em open and working side, as carried in the Tribune article:
"We're pleased with the court's decision, but we know the nuts and bolts of the case are still to be decided," said Darren Melvin, a board member with the Illinois River Carriers Association. "The real issue is, is the threat (of carp) real? To date, regardless of what certain writers have said, the (Sanitary and Ship) canal is not infested with carp. That's just not accurate. In all this talk about the threat there hasn't been enough talk about solutions."People seem to forget that the US Interior Department has operated river structure-based controls for sea lamprey in watersheds of the northern Great Lakes basin. Canada does the same on their side. Ultimately, many political jurisdictions are going to be involved in controlling the movement of Big Head Carp. A federal program that is more collaborative and which includes Canada's participation, is what is needed. One lawsuit between a few states is not going to do the job. Good call, Supremes.
Melvin said industry officials believe the underwater electric barrier built near Lockport has worked as intended, and that they would be in favor of erecting more fish barriers downstate. The U.S. Army Corps of Engineers, which operates the electric barrier, has looked at partnering with state agencies to build barriers that use sound or emit bubbles that could deter carp from advancing north toward Lake Michigan.
German Carp, incidentally are found throughout the Great Lakes watersheds, where they tend to concentrate in estuaries and in the shallower basins like Green Bay. To argue that the Big Head Carp poses a far greater danger to the ecosystem than German Carp begs the question of why? Can they thrive in the colder offshore waters? Will their feeding put them in competition with sport and commercial fisheries? Who says so? Show me the data and hopefully some peer reviewed publications. Until then, keep the lawyers away.
Barrister's wig. Image credit:CostumeBox
FAO has this nice summary of their biology:
Silver carp is a freshwater species living in temperate conditions (6-28 °C) and its natural distribution is in Asia. This species requires static or slow-flowing water, as found in impoundments or the backwaters of large rivers. In its natural range, it is potamodromous, migrating upstream to breed; eggs and larvae float downstream to floodplain zones. While it is fundamentally benthopelagic, as an active species it swims just below the water surface and is well known for its habit of leaping clear of the water when disturbed.Silver carp are typical planktivores, the gillrakers being the main means of filtration. Silver carp consume diatoms, dinoflagellates, chrysophytes, xanthophytes, some green algae and cyanobacteria ('blue green algae'). In addition, detritus, conglomerations of bacteria, rotifers and small crustaceans are other major components of their natural diet. Silver carp spawn in late spring and summer, when the temperature of the water is relatively high. From April to August, either because of the rainstorms or the swollen upper reaches of streams and rivers, its broodstock are concentrated in spawning locations where conditions are favourable, and the current swift, complicated and irregular. Spawning temperature is generally between 18 ºC and 30 ºC, with an optimum of 22-28 ºC. The eggs of silver carp, like all Chinese carps, are non-adhesive. After spawning, the eggs begin to absorb water through the egg membrane and swell until its specific gravity is slightly greater than that of water, so they can stay at the bottom (in the case of static waters) or float halfway in mid-water (in flowing waters) until the fry hatch.
More flying carp posts.
What Jumps In Peoria Today Is In The Human Food Chain Tomorrow ...
Flying Asian Carp, If You Can't Fight 'Em Eat 'Em :
Was it Worth It? One Asian Carp Found After Six Miles of River ...
Swimming to Chicago: Asian Carp
One more horrid example of environmental management by lawsuit.
North Dakota Threatens Suit Against Minnesota, For Even Thinking About Future Carbon Cost