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Entries in invasive species (202)

Tuesday
Mar102015

Corps Suspects Anglers, Hunters of Spreading Hydrilla at Kerr lake

Kerr Lake hydrilla

A management plan for hydrilla control at Kerr Lake (Buggs Island) incorporates a “get tough” approach to those who intentionally introduce the fast-growing exotic plant. The U.S. Army Corps of Engineers is offering a $1,000 reward for information leading to the arrest and prosecution of violators.

That’s because rangers and biologists suspect that anglers and waterfowl hunters are intentionally spreading the invasive.

“It is a crime to knowingly or unknowingly spread noxious and invasive vegetation like hydrilla,” said Mike Woman, project manager for the reservoir on the Virginia-North Carolina border.

He added that the notion that introducing the plant is a good idea is “short-sighted.”

Yes, hydrilla attracts bass and ducks, but it rarely can be contained or controlled. It smothers native plants, as it diminishes oxygen levels and water quality with its biomass. Additionally, recent research has revealed that it can play host to an alga that is deadly to waterfowl and predatory birds that eat them, including eagles.

Hydrilla coverage in the 50,000-acre fishery increased by 230 acres to 1,116 in 2014, puzzling biologists. But then a Corps staffer happened upon internet blogs that extolled the benefits of hydrilla for anglers and hunters. That discovery prompted the agency to conclude that a small number of misguided sportsmen are spreading the plant.

In addition to pursuing these violators, the Corps also has incorporated public education, herbicide application, and sterile grass carp into its strategy.

With assistance from the Virginia Department of Game and Inland Fisheries and the North Carolina Division of Parks and Recreation, the agency stocked 13,320 carp during 2013. Another 4,200 were added in 2014, to make up for an estimated 30 percent mortality with the initial stocking and to address the increase in hydrilla.

The Corps also intends to plant colonies of native, beneficial plants. They will be started in cages to prevent predation by carp and turtles.

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

Thursday
Mar052015

Cue the 'Jaws' Theme and Take a Look at What These Florida Anglers Caught

Florida great white shark

Thinking of heading down to Florida to escape this never-ending winter? Maybe do a little sunning and swimming at the beach?

I’d confine my swimming to daylight hours, and, even then, I might think twice about doing it. That’s because a nearly 10-foot great white and a nearly 11-foot mako shark were caught from shores of northern Florida during the past two weeks.

Appropriately enough, the mako was caught from the pier at Navarre Beach, where much of “Jaws 2” was filmed during the 1970s. The great white came from the surf off Panama City Beach to the east.

And, oh yeah, Joey Polk and his cousins caught an even larger mako at Navarre back in April.

The trio who caught the great white tagged and released it. Polk usually does as well with the sharks he catches.

"We're definitely more on the conservation side of everything," Gabriel Smeby said. "We use big tackle and mainly circle hooks so it puts as little stress on the fish as possible and we can get a tag in them and get them on their way.

"I would say we probably release between 95 and 98 percent of all the sharks we catch."

Florida mako shark

Polk usually releases his sharks as well. But scientists wanted a closer look at a large mako. Anglers kept the meat, while researchers took the backbone, organs, and stomach contents.

No bathers or boats were found inside.

Bighorn River northern pike

Meanwhile, up in Montana . . .

A  Kansas City man caught a 38-inch, 16-pound northern pike while fly fishing for trout on the Bighorn River.

Northern pike are rare for that stretch of the river, especially ones that big. For about 30 miles below Yellowtail Dam - the stretch where the pike was caught - the Bighorn flows cool and clear, making it a productive and popular trout fishery, well-known around the world for rainbows and brown.

How did the non-native pike get in the river? Learn more here.

Tuesday
Feb242015

Mussels Could Be Contributing to Toxic Algae Blooms

Proposed reductions in phosphorous runoff from agricultural lands might not be enough to counter Lake Erie’s increasing susceptibility to toxic algae blooms, according to University of Michigan researchers.

"Our results suggest that current phosphorus loading targets will be insufficient for reducing the intensity of cyanobacteria blooms to desired levels, so long as the lake remains in a heightened state of bloom susceptibility," said lead author Daniel Obenour of the university’s Water Center.

That “heightened state” led to nearly half a million Ohio and Michigan residents being deprived of drinking water for several days in early August because of a cyanobacteria bloom containing the toxin microsystin.

The problem seems to be that the blooms are becoming more sensitive to phosphorus, according to the scientists.

But what has caused this and the corresponding increase in size of cyanobacteria blooms since the mid 1990s? That’s not so easy to explain.

Computer modeling revealed that a special form of phosphorus, DRP (dissolved reactive phosphorus) is more readily absorbed by algae, but it did not explain increased bloom susceptibility. Also, late-summer surface water temperatures did not increase enough to exacerbate the problem.

Exotic quagga and zebra mussels, however, could be a factor. The filter-feeding shellfish gorge on many species of phytoplankton, but avoid those that produce toxins. In other words, the latter now have less competition for nutrients, including phosphorus.

"We tested to see if the increase in the DRP fraction could be the cause, and it did not pass the test. It also does not look like water temperature is driving the increased susceptibility,” said Don Scavia, co-author and aquatic ecologist. “We're thinking it may have been the increase in mussels.

"As long as the lake remains in this heightened state of susceptibility, this problem is likely to persist,” he added. “That means we need to better understand what is driving the increased susceptibility and whether it can be controlled, or if deeper phosphorus reductions are needed.”

Wednesday
Feb182015

How About a Nice, Cold Beer Brewed With Zebra Mussel Shells?

Slowly but surely, the public is awakening to the value of Asian carp as food.

And what possibly could go better with a carpburger than mussel beer?

More specifically, a Milfoil Lakehouse Saison Ale, brewed with zebra mussel shells and Eurasian watermilfoil by Excelsior Brewing Co. on Lake Minnetonka. The beer with the “exotic, invasive flavor” is promoted as a way to heighten public awareness about the problems caused by exotic species.

This past fall, Grumpy’s Limited Action Beer Fest challenged breweries to develop beer using only Minnesota ingredients, and Excelsior decided it wanted to push the envelope. It blended Minnesota wild rice, Minnetonka honey, and local hops with a small dollop of aquatic hitchhikers.

“We thought, ‘We’re going to take this to the extreme,’” said Paul Awad, a spokesman for the brewery. “It ended up being a really great beer.”

He explained that only tiny amounts of milfoil and mussel shells were used, and filtering prevents beer drinkers from finding a trace of the ingredients in their glasses. “Neither of them adds a lot of flavor. It’s more the novelty of it,” he said, adding that the brew tastes like many Saisons, with fruity, spicy overtones.

Ryan Anderson from MNbeer.com wasn’t particularly surprised by the mussel/milfoil beer. “There are some breweries out there trying some crazy things,” he said.

For example, seaweed as an added ingredient is becoming more common, while other micro breweries are trying things like fish bladders and oyster shells.

“It’s definitely a kind of interesting thing,” he said of the Excelsior beer. “But stranger things have happened.”

Meanwhile, a spokesperson for the Department of Natural Resources said the exotic brew “sounds really unusual.”

Before this latest offering, Excelsior already created beers that honored its lakeside location, including Big Island Blond Ale. Additionally, 1 percent of its profits support the popular fishery via donations to organizations such as the Freshwater Society.

Meanwhile, in the Cafeteria . . . 

The University of Missouri is testing recipes and gathering reactions as it considers adding the invasive Asian carp to the menu in its dining halls.

About 40 students tried different recipes using the fish during recent taste tests at the Sabai Culinary Development Kitchen on the Missouri campus, and their reactions will help the culinary staff decide whether to serve the fish.

Monday
Jan192015

Divers Capture Another Invader in Florida Waters

Surgeon fish photo by Deb Devers

Congratulations to two divers who had the good sense to report and then capture an exotic fish. Their actions might have prevented its establishment in Florida waters.

The two first noted the small, bright yellow fish while SCUBA diving beneath Palm Beach County’s Blue Heron Bridge, and realized that they never had seen one like it. They took photos and later reported what they had seen to the Reef Environmental Education Foundation (REEF), a non-profit that keeps track of exotic marine fish species.

According to the Miami Herald, REEF identified the fish as a mimic lemon peel surgeonfish, also known as a chocolate surgeonfish. It’s native to the Indo-Pacific, and this was its first sighting in Florida waters. Upon learning that, the divers returned to where they had first seen the fish and captured it.

"We don’t know what the effects would have been if the fish had become established and began reproducing,” REEF said. “But if we wait to find out, then it’s too late.”

Taking out the surgeonfish could prove to be the fourth preemptive strike against a non-native marine fish species in Florida coastal waters, according to the organization.

In 1999 and 2002, REEF staff and volunteers captured four large Indo-Pacific batfish from Molasses Reef in Key Largo. In 2009, they removed a whitetail dascyllus damselfish from the east side of the Blue Heron Bridge. In 2012, Miami divers Greg Caterino and Wayne Grammes speared an exotic humpback grouper on a reef off Biscayne National Park and turned the carcass over to REEF. None of those three species are known to have reappeared in Florida waters since their removals.

“Some people might say, ‘Oh big deal, we took this little fish out of the water,’” REEF said. “But that’s the way the lionfish got started. If only we could have taken the first few lionfish out of the water in the first place. We’re relying on divers, snorkelers and fishermen to be our eyes and ears on the water. It’s a perfect example of how early detection and rapid removal can be successful in stemming an invasion.”

Anyone who spots a strange-looking fish that they suspect is invasive is advised to take a photo and report the sighting to REEF.