This area does not yet contain any content.
Get Updates! and Search
No RSS feeds have been linked to this section.

 

 

 

 

 

 


 

 

 


 

 

 

Entries in exotic species (162)

Monday
Apr142014

Strategies Improve for Controlling Hydrilla; Giant Salvinia Grows as Threat to Fisheries

Hydrilla has joined Eurasian milfoil as an invasive exotic plant that threatens northern fisheries. It now has been found in Kansas and Missouri, and the Nature Conservancy is reporting “a number of populations on the doorstep of the Great Lakes.”

Giant salvinia, meanwhile, has emerged as a significant danger to some southern waters, especially in eastern Texas and Louisiana.

Yet much of the news these days is good for anglers in regard to troublesome aquatic plants, particularly hydrilla. Resource managers assert that they have learned from past mistakes and now strive to control this fish-attracting invasive, rather than obliterate it.

“We’re not trying to wipe it (hydrilla) out anymore,” said Howard Elder, aquatic plant biologist with Texas Parks and Wildlife. “We’re trying to find a happy median.”

Bill Caton, leader of the Invasive Plant Management Section at Florida’s Fish and Wildlife Conservation Commission, echoed the sentiment, emphasizing that “spot treatment” is preferred.

“It’s like treating weeds in a flower bed,” he said. “It’s much better if you don’t let it get out of control. If you do, then it costs you more, you have to use more herbicides, and you have more dead vegetation to deal with.”

Caton acknowledged that sometimes the aftermath of a herbicide treatment for hydrilla and other invasives still “can look bad” to anglers.

“But the public is just looking at the immediate impact of the treatment and not thinking about the results,” he said. “Treatments are like prescribed fires. They can look bad, but they’re often the only alternative that we have for providing good fish and wildlife habitat and preserving places for people to fish.”

Mechanical harvesting, he added, “is too expensive and destroys everything,” including fish and invertebrates trapped in the plants.

Grass carp, meanwhile, are an option in some states, including Texas and South Carolina.

“We knock the hydrilla back with herbicides and then use grass carp for control,” Elder said.

For the massive Santee Cooper system, the exotic grass-eaters are the preferred primary tool, and Chris Page, manager for the aquatic plant program at the South Carolina Department of Natural Resources, believes  balance has been achieved with this method as well.

“We do maintenance stocking of one fish per eight acres,” Page said. “That’s about 20,000 fish. And we’re going to put in another 10,000 to manage an additional 400 acres of (hydrilla) coverage.”

Such a formula is a far cry from the 700,000 fish stocked in the 160,000-acre system from 1989 to 1996, he explained.

“I understand the problem that the public had with that. There were too many carp for several years.”

But as they better manage hydrilla, state agencies also are challenged with new threats to fisheries, including crested floating heart (see below) and giant salvinia.

Unlike hydrilla, giant salvinia has no redeeming value as fish habitat, and it can double in area in 10 days or less. It destroys primary productivity in a fishery and acidifies water until only a desert remains under its canopy.

In Texas, giant salvinia is established in 12 lakes. It also has spread to Louisiana, California, Arizona, and New Mexico, as well as other states.

“Hydrilla is a greater threat overall because it is so popular and so widespread,” Elder said. “Giant salvinia is not as easily distributed and it prefers acidic waters, which is why it is a threat in east Texas.”

This latest invader also is more difficult to control with herbicides than hydrilla, and carp won’t eat it. That’s why both Texas and Louisiana are raising weevils that will feed on the exotic plant.

New Invader

There’s a new bad kid on the block: crested floating heart. It’s been in Florida for awhile, and now is causing problems in South Carolina.

Chances are good that this native of Asia also is established in other states, but hasn’t yet been identified. With flat, floating leaves and white flowers, it resembles the native banana lily, according to the Center for Aquatic and Invasive Plants (CAIP) at the University of Florida.

“I think that this could be a bad one,” said Mike Netherland, an aquatic plants expert for the Army Corps of Engineers.

As with so many other exotic plants now degrading our waterways, it likely “escaped from a water garden somewhere,” according to Chris Page, program manager for aquatic plant management in the South Carolina Department of Natural Resources.

Within four to five years, crested floating heart spread from 10 to 15 acres to 2,000 in the 160,000-acre Santee Cooper system, he added.

“We’ve done some (herbicide) treatment in coves, where there’s no water movement,” said Page, adding that effective application is difficult in open water.

“It’s the most aggressive floating-leave plant that we’ve encountered on the lakes,” said Larry McCord, supervisor of analytical and biological services for the Santee Cooper power and water utility. “It is rooting in high-energy areas along the main shoreline and can grow quite successfully in 10 to 12 feet of water.”

In Santee Cooper’s lakes Moultrie and Marion, this invasive exotic has the potential to spread over 40 percent of the acreage, McCord explained. Plus, reports from Asia suggest that grass carp won’t eat the plant, not good news for a waterway where they are used to control hydrilla.

Once established, cresting floating heart blankets the surface, blocking light penetration to beneficial submersed plants.

In Florida, according to CAIP, the invader is considered a Category II ecological threat. That means it has increased in abundance, but has not yet altered Florida plant communities to the extent shown by Category I species (hydrilla).

(A variation of this article was published in B.A.S.S. Times a few years ago.)

Friday
Apr042014

Minnesota Politicians Get Tough on 'Asian' Carp

Congratulations to Minnesota politicians for serving as a shining example to the rest of the nation, as they deal with the most critical issue related to decimation of our waterways by Asian carp.

What is that issue? How can you ask such an inconsiderate question!

Of course it’s designating a new name for the exotic invaders so that no one is offended. During this utopian era of political correctness, when some want to ban the word “bossy,” what more noble endeavor could there be for those paid by taxpayers?

“Caucasians brought them to America,” said John Hoffman, a Democrat state senator who is sponsoring the bill. “Should we call them ‘Caucasian carp’? They have names. Let’s call them what they are.”

The executive director of the Council on Asian-Pacific Minnesotans added that the term “Asian carp” will cause people to “reflect negatively on our community.”

A spokesperson for the Minnesota Department of Natural Resources (DNR), meanwhile, testified that her agency was unaware of any comments from the public that “Asian carp” is offensive.

Those folks at DNR should be ashamed of themselves. They should have been on top of this months ago, as should legislatures in other states where these insensitively named invaders are destroying fisheries.

Don’t they know it’s not about whether people are offended? It’s about an obsessive need for government to eliminate the slightest possibility that people might be offended.

As soon as the enlightened Minnesota politicians force DNR to start referring to Asian carp as “invasive carp,” then they could get to work on renaming Eurasian watermilfoil, a troublesome exotic plant that has spread into many state waters. That threatens to offend people of not only Asian descent, but European as well.

And I don’t even want to think about how the zebras in Como Park Zoo in St. Paul must be suffering because of those inappropriately named mussels.

And here are some other offensive names of exotic species that we must get rid of, never mind that they simply are named after geographic areas from which they originated:

African honeybee, Brazilian pepper, Burmese python, Canada thistle, Chinese mitten crab, Cuban tree frog, English ivy, Japanese honeysuckle, and New Zealand mud snail, just to name a few.

Oh, yeah, and there’s Asiatic witchweed, Asian tiger mosquito, Asian lady beetle, Asian long-horned beetle . . .

Tuesday
Apr012014

Invasive Species Top List of Tourism Concerns in Michigan

Invasives species, including Asian carp, rank at the top of concerns by Michigan tourism professionals.

Tourism industry professionals in Michigan were asked to “identify key issues facing and threats to the integrity of Michigan’s tourism resources.” Since Michigan is a Great Lakes state, the results are not surprising: Invasive species rank as the top threat.

The tourism folks know what they’re talking about, not only for Michigan, but for much of the rest of the country as well.

As a matter of fact, I think that they correctly have identified the top four for many of the states, and they have appropriately placed climate change and increasing the number of wind farms where they belong--- at or near the bottom.

Sadly, a good number of them have bought into the environmental left’s hatred of fracking, when no evidence supports the notion that it poses a threat to our lands and waters. In fact the former head of the U.S. Environmental Protection Agency, Lisa Jackson, said unequivocally that her agency has found no evidence of contamination.

  • Spread of invasive species (aquatic & terrestrial) – 65.2 percent
  • Lack of/limited funding for resource protection/maintenance – 59.5 percent
  • Declining water quality of our lakes, rivers and streams – 42.7 percent
  • Declining water levels of our lakes, rivers and streams – 41.3 percent
  • Diversion of water from the Great Lakes – 39.3 percent
  • Reduction in historic preservation tax credits – 28.9 percent
  • Closure of Department of History, Arts and Libraries – 25.1 percent
  • Fracking – 24.5 percent
  • Need for better/faster adoption of technology at tourism sites – 20.8 percent
  • Under-appreciation of Native American history and culture – 20.0 percent
  • Climate change – 16.8 percent
  • Spread of infectious diseases – 8.5 percent
  • Increasing number of wind farms – 7.7 percent
Friday
Mar282014

Mapping the Invasion

This screen shot shows zebra and quagga mussel invasion as of 2006.

Nature Conservancy has produced some great interactive maps showing how invasive aquatic species have spread out across the country from their point of introduction.

Featured species include bighead and silver carp, zebra and quagga mussels, Eurasian ruffe, round goby, sea lamprey, and black carp.

Also, in late 2012, the organization released a report saying that aquatic invasive species “cost businesses and consumer in the Great Lakes region hundreds of millions of dollars annually in direct costs and even more from indirect costs related to removal, maintenance, and management of those species.

“Meanwhile, state and federal governments are currently forced to spend additional millions as they attempt to control the impacts and prevent the spread of AIS (aquatic invasive species).”

According to the report, the largest industry affected by AIS in the Great Lakes is tourism and recreation, which is responsible for employing more than 90,000 people in the region, generating $30.3 billion annually in revenue. Costs range from monitoring and controlling AIS to lost revenue from beach closings affecting hotels, restaurants and other tourism-related businesses.

Wednesday
Mar262014

Third Carp Species Also Threatens Great Lakes

Activist Angler caught this 30-pound-plus grass carp in a lake that has been damaged by illegal stocking of this exotic species. Photo by Robert Montgomery.

When people talk about Asian carp threatening the Great Lakes and its fisheries, they typically are referring to bighead and silver.

But a third species also potentially could damage this vast freshwater ecosystem if it becomes established in substantial numbers.

The grass carp was introduced into U.S. waters about 50 years ago, with the intent of using it to manage invasive aquatic vegetation. It has done its job--- and then some. Too often it has obliterated all vegetation in a water body, including beneficial native plants.

Additionally, it has escaped and established wild populations, as did the bighead and silver. Today the grass carp is believed to be in at least 45 states.

And now this invader poses danger for the Great Lakes.

Researchers recently documented that grass carp have spawned in the Great Lakes, specifically in Ohio’s Sandusky River, a tributary of Lake Erie. They also point out that 45 of them were caught in the Great Lakes between 2007-2012. That’s not a lot, but it’s 45 too many, especially since about half of those were capable of reproducing, meaning that an established population might already exist.

That does not bode well for bass, pike, and other inshore species that thrive in and around aquatic vegetation.

Read more here.

By the way, I have personal experience with grass carp. Years ago, ignorant property owners illegally stocked grass carp in the little lake behind my house because, they said, “they filter the water and improve the water quality.”  They did so, even though the lake contained little, if any, aquatic vegetation.

Somehow, the carp have survived and today some of them weigh 30 pounds or more. They’re the equivalent of big aquatic cows, degrading water quality, not improving it, as their wastes feed alga blooms during summer.

Also, hundreds of pounds of carp prevent growth of hundreds of pounds of bass, bluegill, and catfish. Like a farm field, a lake can sustain just so much biomass.