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Entries in Mississippi River (40)

Thursday
Aug212014

Sky Isn't Falling, But Dead Zones Are Real

The Mississippi River dead zone is overloaded with nutrients from upstream sources. This photo shows the color change between the hypoxic (brown) and oxygen-rich (blue) waters. Photo courtesy of NOAA.

Climate change occurs naturally. It always has, and it always will vary from day to day, week to week, season to season, year to year, decade to decade, and century to century. Possibly humans play a role in that change in some way, but no verifiable evidence supports that. Even if it did, we, as one nation, could do little to nothing about it because our contribution is miniscule compared to what’s happening in China, India, and the rest of the world.

The billions of dollars wasted on this sky-is-falling hysteria could be far better spent on providing food and clean water to the millions who need it.

By contrast, dead zones pose legitimate threats to our fisheries and oceans and could be minimized if we changed our ways.

LiveScience.com reports the following:

“Agricultural practices are the biggest culprit for dead zones in the United States and Europe. Rains wash excess fertilizer from farms into interior waterways, which eventually empty into the ocean. At the mouths of rivers, such as the Mississippi, the glut of phosphorous and nitrogen intended for human crops instead feeds marine phytoplankton.

“A phytoplanktonic surge leads to a boom in bacteria, which feed on the plankton and consume oxygen as part of their respiration. That leaves very little dissolved oxygen in the subsurface waters. Without oxygen, most marine life cannot survive.”

In the United States, the most notorious dead zone occurs each summer in the Gulf of Mexico, spreading out from the mouth of the Mississippi River. This year, it consumes more than 5,000 square miles, slightly smaller than last year. On average, it is estimated to cost $82 million annually in diminished tourism and fishing yield.

More than 150 dead zones have been identified in this country, most of them along the coasts. A few occur inland, notably the Great Lakes.

Some of them have been cleaned up through improved management of agricultural runoff and sewage. But as fertilizer and factory farming both increase, LiveScience.com warns, “the United States is creating dead zones faster than nature can recover.”

More than 400 dead zones have been identified worldwide, covering about 1 percent of the area along continental shelves.  But likely many more than that exist, since portions of Africa, South America, and Asia have yet to be studied.

Wednesday
Mar122014

Asian Carp Eggs Found in Upper Mississippi River

 

Just when we think that we know what is going on with Asian carp . . . 

The U.S. Geological Survey (USGS) says that researchers found eggs, including late-stage embryos, in samples collected last summer from the Upper Mississippi River, as far north as Lynxville, Wisc. 

Here's more from the USGS:

"This discovery means that Asian carp spawned much farther north in the Mississippi than previously recorded," said Leon Carl, USGS Midwest Regional Director. "The presence of eggs in the samples indicates that spawning occurred, but we do not know if eggs hatched and survived or whether future spawning events would result in live fish."

The Asian carp eggs and late-stage embryos were discovered two weeks ago while processing samples that were collected in mid-May and mid-June, 2013. The samples were taken as part of a larger research project designed to identify Asian carp spawning habitats. The eggs and late-stage embryos were 250 river miles upstream of previously known reproductive populations in the river. Spawning would have occurred upstream from this site.

Once the scientists visually identified the eggs, they examined other samples taken from the Mississippi River and found Asian carp eggs at seven locations between Pool 19 near Keokuk, Iowa, and Pool 9 of the main channel of the Upper Mississippi River near Lynxville. Iowa, Missouri, Illinois, Minnesota and Wisconsin border the navigation pools where these samples were collected.

The eggs and late-stage embryos were identified as bigheaded carps — either bighead carp or silver carp — through visual analyses of specific features of the eggs and embryos. It is also possible that some eggs could be from grass carp, although no eggs were visually identified as such. The USGS attempted genetic analyses to definitively determine which species of Asian carp the eggs belong to, but the results were inconclusive. Additional steps are being completed to attempt genetic confirmation, and those results are expected in one to two weeks.

The research project that collected these eggs is being coordinated by the USGS in collaboration with Western Illinois University. Scientists plan to collect additional samples from the Mississippi River in 2014 as part of their on-going research project.

"Invasive Asian carp could pose substantial environmental risks and economic impacts to the Upper Mississippi River if they become established," Carl said. "Further research will help us to better understand their habitat requirements and inform integrated control efforts."  

Friday
Feb142014

Electric Barrier Is NOT Stopping Fish

Oh, yeah! That electric barrier is going to keep Asian carp from entering Lake Michigan via a manmade connection to the Mississippi River basin.

Or maybe not.

A video obtained by the Milwaukee Journal Sentinel shows small fish swimming through the electrified water, just 35 miles downstream from Chicago’s lakeshore.

And no one said that the invaders must be adult fish.

“The only thing holding back the Asian carp at the moment is the electric barrier, but few people beyond Illinois politicians, the canal-dependent barge industry, and the Army Corps are buying the idea that the barrier is doing its job. Many worry the agency's continued confidence in this leaky, last line of defense will take a tragic toll on the Great Lakes, the world's largest freshwater system,” said the newspaper.

Thursday
Feb062014

Invasive Species Threat Goes Both Ways

Mostly resource managers have been concerned about Asian carp invading the Great Lakes through a manmade connection with the Mississippi River basin. But exotics already in the lakes also could migrate out and spread into rivers throughout the Midwest, if the electric barrier separating the two systems is not 100 percent effective.

One of those is the Eurasian ruffe, a small perchlike fish that entered Lake Superior during the mid 1980s in the ballast water of European freighters. It then spread to Lakes Michigan and Huron, and, this past summer, researchers found ruffe DNA in Chicago’s Calumet Harbor.

“The Eurasian ruffe is a relatively small fish that produces a lot of eggs and reaches maturity very quickly,” said Lindsay Chadderton, Aquatic Invasive Species Director for The Nature Conservancy’s Great Lakes Project. “They feed from the bottom of the food chain, and they’re going to compete with native and introduced species dependent on the same fauna.”

On the positive side, Illinois officials emphasized that no live ruffe have been captured in the harbor. They said that the DNA could have come from a bait bucket or ballast tanks, not an actual fish.

Still, even the possibility that the ruffe could be poised to spread inland underscores how vulnerable both the lakes and the Mississippi River basin are to invasive species and the need for an effective two-way barrier, according to The Nature Conservancy and other conservation groups.

(This article appeared originally in B.A.S.S. Times.)

Friday
Dec272013

Electric Barrier Isn't Keeping Fish Out of Lake Michigan

 

You know that expensive electric barrier erected to keep carp out of the Great Lakes?

Uh, well, that isn’t working so well, according to a new report from the Army Corps of Engineers. That’s because small fish can ride in on the flow behind barges crossing the barrier.

In a new report, the Corps says the following:

"Initial findings indicate that vessel-induced residual flows can trap fish and transport them beyond the electrical barriers, and that certain barge configurations may impact barrier electric field strength. Additionally, the preliminary (sonar camera) findings identified the potential for small fish (between 2-4 inches in length) to pass the barrier array in large groups, or schools."

Crews dropped in a camera 10 minutes at a time to see what was happening. In 61 percent of the 72 samples, they saw entire schools of fish, “not believed to be Asian carp,” swimming through.

But not to worry:

"There is no evidence that Asian carp are bypassing the barriers. Nor is there any indication that Asian carp are in the vicinity of the barriers," states the report. "The closest adult Asian carp found in the Illinois River are about 55 miles from Lake Michigan, and no small Asian carp have been observed closer than 131 miles from Lake Michigan."

So . . . it’s okay that we are spending millions of dollars to maintain a barrier that doesn’t work because, well, it doesn’t have to work because the Corps says the invaders are far, far away and don’t pose a threat.

Gee, that makes me feel so much better. I have to wonder, though, if the Corps is as competent at estimating the threat as it is at defending against it.