Here in the Upper Midwest, one of the more notorious invasive species is the flying carp, and for residents of the Great Lakes, the enemy is at the gates.

The decade-old battle to keep Asian carp out of the Great Lakes may be over.

New research shows the super-sized fish likely have made it past the $9 million electric fish barrier on the Chicago Sanitary and Ship Canal

Now the only thing left standing between the fish and Lake Michigan is a heavily used navigational lock at Navy Pier.

Dave Dempsey at Planetsave quotes an official who points out that no actual carp body has yet been found beyond the barrior. Once that happens, of course, it’s pretty much too late.

Last-ditch efforts to stop the carp could include poisoning the entire canal. That’s an extreme measure, and there’s already reason to wonder if it could be done fast enough.

Invasive species that spread through water are always difficult to deal with, zebra mussels, flying carp, and millfoil are all well-known examples here in the Midwest. Imagine, though, an invasive species spreading through the ocean, taking advantage of changing conditions to ruin life for everything else.

No need to imagine it. They’re already here.

They’re known as “cockroaches of the sea,” and swarms of supersized jellyfish are growing even larger and more menacing as Earth heats up, the AP reports. The hardy scavengers benefit from almost anything that hurts other ocean dwellers — sort of bizarro-world canaries in the coal mine — and some scientists are worried climate change could be their key to world domination. Overfishing has already obliterated many of their top predators, and pollution has helped proliferate the plankton they eat, but marine biologists have also begun noticing strong correlations between warmer ocean temperatures and exploding jellyfish populations.

Florida is the center of a growing problem with invasive snakes.

Five giant exotic snake species already in the United States would pose high risks to the health of U.S. ecosystems if they become established here, according to a new U.S. Geological Survey report.

The USGS report details the risks of nine non-native boa, anaconda and python species that are invasive or potentially invasive in the United States. Because all nine species share characteristics associated with greater risks, none was found to be a low ecological risk.

Three of these species are documented as reproducing in the wild in South Florida, with population estimates for Burmese pythons in the tens of thousands.

It’s a classic situation, native species have no defenses against the invaders which quickly spread and establish themselves throughout the territory. The kicker here is that these snakes were almost all imported as pets, then either released or escaped in to the wild.

There’s an allure to exotic pets, but the consequences of letting them loose can be quite severe. Take, for example, what happened in Guam.

“We have a cautionary tale with the American island of Guam and the brown treesnake,” said (Dr. Robert) Reed. “Within 40 years of its arrival, this invasive snake has decimated the island’s native wildlife - 10 of Guam’s 12 native forest birds, one of its two bat species, and about half of its native lizards are gone. The python introduction to Florida is so recent that the tally of ecological damage cannot yet be made.”

Let’s hope these latest invading snakes are brought under control before the tally of ecological damage in Florida begins to resemble that of Guam.

When a predator moves into a new environment where there’s nothing to slow it down, it doesn’t take long before it starts preying on everything in sight, or, this case, swim.

In 1992, Hurricane Andrew smashed an aquarium tank in Florida. About a half-dozen spiny, venomous lionfish washed into the Atlantic Ocean, spawning an invasion that could kill off local industry along with the native fish.

They’re hard to miss with their red and white stripes and a tall row of venomous spines down their backs. The fan-like fins look like a lion’s mane. And like lions, they are ferocious predators. Last year, (Mark) Hixon co-authored a study with Mark Albins that showed a lionfish can kill three-quarters of a reef’s fish population in just five weeks.

Loking for good news? There just may be another predator around that can do something about the lionfish eating everything in sight.

Until marine predators or parasites learn to feed on lionfish, the best hope for slowing the spread may be humans. The fish are a delicacy in Asia, but not in the Bahamas, given the painful sting their spines can inflict. A few restaurants serve lionfish now, and there’s an effort to teach Bahamians how to catch and cook them.

I can see the ad campaign already: Eat a lionfish, save a reef.

The first quagga mussels were seen in Lake Mead about two years ago, and by all accounts the situation is already getting out of hand.

A big part of the problem is Lake Mead’s size, there’s no way anyone can monitor all the places available for boats to leave the water. That means any chance of halting the spread of quagga mussels throughout the west is going to depend greatly on boaters cleaning their boats whenever they transport them from one lake or river to another. Even one mussel can become millions, and just to highlight the problem, it’s already happening.

In Oregon, a new law prohibits the launch of any boat with any aquatic species on it. Randy Henry of the Oregon Marine Board said that’s an simple standard to enforce. A campground host or anyone else can “look at a boat and say, ‘There’s green stuff on your boat - please don’t launch it, or we’ll call the police,” he said.

Montana identified and decontaminated a boat coming back from Lake Mead just last week.

The usual story with an invasive species is the new species moves in, the natives are pushed out, people try to fight back but eventually settle for just trying to contain the problem, at best.

Every once in a while, though, the invaders are successfully driven out.

Alaska’s Rat Island is finally rat-free, 229 years after a Japanese shipwreck spilled rampaging rodents onto the remote Aleutian island, decimating the local bird population.

After dropping poison onto the island from helicopter-hoisted buckets for a week and a half last autumn, there are no signs of living rats and some birds have returned, according to the U.S. Fish and Wildlife Service.

Rats have ruled the island since 1780, when they jumped off a sinking Japanese ship and terrorized all but the largest birds on the island. The incident introduced the non-native Norway rat — also known as the brown rat — to Alaska.

The $2.5 million Rat Island eradication project, a joint effort between the U.S. federal government, the Nature Conservancy and Island Conservation, is one of the world’s most ambitious attempts to remove destructive alien species from an island.

And they didn’t even have to call in the Pied Piper.

Things have a way of balancing out. For example, if the federal government spends years ignoring a problem like the introduction of invasive species in the Great Lakes by way of ship ballast water, it shouldn’t come as to great a shock when states like New York start taking action themselves.

The New York State Supreme Court has upheld the state’s authority to require large ships dumping ballast water in state waters to meet a stricter standard than that of the federal government.

Ballast water is carried in unladen ships to provide stability. At the ships’ destination, cargo is loaded and the ballast water, carrying stowaway organisms, is pumped out. Untreated vessel ballast discharges have introduced more than 180 aquatic invasive species into the Great Lakes. Lake Erie and Lake Ontario border western New York.

The court rejected the arguments of a coalition of large shipping interests that claimed the state had illegally placed further restrictions on a U.S. Environmental Protection Agency nationwide discharge permit for these vessels.

Like California and greenhouse gas emissions, the Great Lakes states are moving farther than the federal government would like to go. Maybe that’s because they’re the one swho most directly live with the consequences of those problems, whether they be polluted skies of lakes filled with strange, alien creatures.

For much of human history, we have tended to think of the number of fish in the sea as an endless quantity. Unfortunately, that belief is looking more and more like an illusion.

Sharks and barracuda disappear on Caribbean coral reefs as human populations rise, endangering the region’s marine food web, its reefs and its fisheries, finds a new study by researcher Chris Stallings of the Florida State University Coastal and Marine Laboratory.

Stallings says overfishing is the most likely cause of the Caribbean’s present lack of big fish.

With far more detail at a greater geographic scale than any other research to date, Stallings examined 20 species of predators, including sharks, groupers, snappers, jacks, trumpetfish and barracuda, from 22 Caribbean nations.

“I found that nations with more people have reefs with far fewer large fish because as the number of people increases, so does demand for seafood,” said Stallings.

“Fishermen typically go after the biggest fish first, but shift to smaller species once the bigger ones become depleted,” he said. “In some areas with large human populations, my study revealed that only a few small predatory fish remain.”

When you get right down to it, the only thing that can be changed in this equation is human behavior. Either we learn to act with some restraint and manage the ocean’s resources responsibly, or face the consequences.

“Large predatory fish such as groupers and sharks are vitally important in marine food webs,” Stallings said. “However, predicting the consequence of their loss is difficult because of the complexity of predator-prey interactions. You can’t replace a 10-foot shark with a one-foot grouper and expect there to be no effect on reef communities. Shifts in abundance to smaller predators could therefore have surprising and unanticipated effects. One such effect may be the ability of non-native species to invade Caribbean reefs.”

A case in point, said Stallings, is the ongoing invasion by Pacific lionfish, which were introduced by aquarium releases.

“Lionfish are minor players on their native Pacific reefs, yet they are undergoing a population explosion and overeating small fishes in the greater Caribbean region,” said Professor Mark Hixon of Oregon State University, Stallings’ doctoral advisor at OSU.

Here’s some bad news for all of us who love the lakes and streams of the Minneapolis - St Paul urban area.

Zebra mussels may be infesting Prior Lake, which would make it the first recreational lake in the metro area to be invaded by the tenacious pest. The discovery is adding urgency to efforts to halt the spread of invasive species to other Twin Cities waters, including Lake Minnetonka.

The DNR is following a homeowner’s report of zebra mussel shells on a Prior Lake beach, and won’t make a final determination until the water warms and divers can explore the water, but “likely it’s infested,” said Luke Skinner, supervisor of the DNR invasive species unit.

If the mussels make it into Lake Minnetonka, it’s pretty much over. From there, creeks and streams connect to almost all the other lakes west of the Mississippi. There will be no stopping them.

The plight of salmon in the Pacific Northwest is pretty well known, dwindling numbers have forced the cancellation of entire fishing seasons. But an article published today by the American Institute of Biological Sciences suggests that the salmon may be suffering from more than the usual suspects of dams, water-pollution, and over-fishing. It’s our old friend, the invasive species.

That conclusion by itself might not be so surprising, but from the perspective of the Midwestern U.S. it’s interesting to note what, in this case, the invading species are.

(Beth L.) Sanderson and colleagues therefore assembled reports of predation by 6 of the 60 nonindigenous fish species found in the region: catfish, black and white crappie, largemouth bass, smallmouth bass, walleye, and yellow perch. These aggressive, introduced predators consumed hundreds of thousands to millions of juvenile Pacific salmonids at just a handful of sites, and, for some of the species, salmonids constituted a large fraction of their diet.

Walleye, bass, perch, crappie, in the Midwest these are what most people are trying to catch, and eat. It goes to show that almost any species can become a nuisance when it gets into a new environment. In a wrld of global travel and shipping, that’s a problem that’s not going away any time soon.