The anticipated three-day legal showdown begins Tuesday in federal court as attorneys from Michigan, Ohio, Pennsylvania, Wisconsin and Minnesota will try to persuade U.S. District Judge Robert Dow that Asian carp pose such a grave threat to the Great Lakes that nothing short of an emergency shutdown of the system will stop them.

At a preliminary hearing last week, Michigan’s Assistant Attorney General Robert Reichel told Dow the U.S. has reached a “biological tipping point” for invasive species threatening the Great Lakes. He said closing the locks, which open to regulate water levels and permit the passage of boats and ships, is perhaps the only way to keep Asian carp out of the Great Lakes and protect its estimated $7 billion annual commercial and recreational fishing industry.

Attorneys representing the U.S. Army Corps of Engineers, which operates the locks, argued the federal government has spent millions of dollars to monitor and stop Asian carp on their march up the Illinois River. They say closing the locks may not be effective and could make the problem worse.

NEWS RELEASE -INTERNATIONAL LAKE SUPERIOR BOARD OF CONTROL

*****************************
Temporary closure of Gate 1 and update on Lake Superior outflow

The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission, has set the Lake Superior outflow to 1,560 cubic meters per second (m3/s) (55.1 thousand cubic feet per second (tcfs)) for the month of September, effective September 3.

This is the outflow recommended by the regulation plan for the month of September and is the same as the August outflow.

The September outflow will be released by discharging about 1,440 m3/s (50.9 tcfs) through the three hydropower plants and passing most of the remaining flow through the control structure at the head of the St. Marys rapids.

The gate setting of the control structure will be maintained at the existing setting equivalent to one-half gate open (four gates open 20 cm, or about eight inches each).

The International Joint Commission has granted authority to Brookfield Renewable Power to make temporary closures of Gate 1 that supplies the Fishery Remedial Works.

No one knew about the doughnut in southern Lake Michigan, much less the mollusk, until Michigan Technological University biologist W. Charles Kerfoot and his research team first saw it in 1998. That’s because scientists have always been wary of launching their research vessels on any of the shipwreck-studded Great Lakes in winter. But NASA’s new Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project was giving scientists a safer way to look at the lakes in bad weather. SeaWiFS satellite data showed Kerfoot’s team a roughly circular river of phytoplankton—algae and other tiny plants—that was drifting counterclockwise around the southern end of Lake Michigan, creating a doughnut.

The group determined that the doughnut was formed when big winter storms kicked up sediments along the southeastern shore of the lake. There, Michigan’s biggest rivers drain a watershed rich in phosphorus and other nutrients from cities and farms. Those nutrients settle in the lake’s sediments until storms stir them up.

Over the past few weeks, fisheries biologists for the Ohio Division of Wildlife have been looking for 5- to 7-inch walleye born last spring in order to rate the 2010 hatch. The experts may have been looking in the wrong places.

Lake Erie Supervisor Jeff Tyson said Thursday that levels of dissolved oxygen in the water around half of their survey sites were down to about 1 part per million, or less. The lack of dissolved oxygen, said Tyson, has chased walleye away from their usual haunts in and around the western lake islands and eastward into the Central Basin of Lake Erie, where the notorious oxygen-depleted “dead zone” has been studied in recent years.

“When you look at the category of wild or natural reproduction, it’s still pretty pathetic for Lake Michigan,” said study co-author Chuck Madenjian, a fish biologist with the U.S. Geological Survey’s Great Lakes Science Center.

“For all we know, it’s still close to being a goose egg.” he said. “Zero.”

Low stocking numbers, two invasive species and even a native fish are all to blame.

The study reports 14 years worth of lake trout surveys within the northern-most of the no-fishing zones.

Biologists looking for baby lake trout in this 860-square-mile Lake Michigan refuge where fishing for the species is banned found none in 14 years of looking.

Biologists dragged nets around the refuge scouting for wild lake trout less than a year old. Finding such a young fish means that it was probably born nearby. That helps measure the area’s productivity as a lake trout nursery.

But in 14 years of looking, they found none.

A 2008 survey turn up six adult wild lake trout, but biologists guess that they were already four years old. It’s less likely that they were born in the refuge because no two- or three-year old wild fish were caught in the years before.