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Entries in exotic species (166)

Tuesday
Jul012014

Loss of Access Threatens Future of Fishing

Anglers are losing access to their favorite fisheries.

Sometimes, it’s because of development or budget cuts. Other times it’s because government bodies or even private groups have shut down public launch areas.

The latter is happening with increasing frequency because of a fear that invasive species such as zebra mussels and Eurasian watermilfoil will be accidentally introduced via contaminated boats and trailers. Sometimes the concern is legitimate. Other times, it’s simply an excuse to keep out the public.

This threat has grown so severe that one in five anglers surveyed by AnglerSurvey.com reported having to cancel or quit fishing a particular location in 2011 because they lost access to it. Most were able to shift their fishing to another location, but a third of affected anglers said that the loss caused them to quite fishing altogether.

“While access issues can often be overcome by fishing somewhere else, we are still losing some anglers each year due to problems with fishing access,” says Rob Southwick, president of Southwick Associates, which conducts the surveys at AnglerSurvey.com.

“When we add up the anglers lost year after year, whether as a result of marine fishery closures or dilapidated boat ramps, access remains a major long-term problem for sportfishing and fisheries conservation.”

You can help slow down this loss of access and possibly even reverse the trend.

First, be a responsible angler by making certain that you do not allow invasive species to hitchhike on your boat and/or trailer, and encourage others to do the same. When fishermen set good examples, those in power have less reason to try to deny access. Additionally, if you belong to a fishing club, encourage it to work cooperatively with lake associations and government bodies on plans to keep out invasive species.

Also, familiarize yourself with access issues, both locally and nationally. Attend public meetings when access issues are on the agenda. Write letters, send e-mails, and make phone calls to officials, emphasizing that quality access is important.

Solution: Make sure you leave every area better than you found it, be committed and vocal about preventing the spread of invasive species, and get involved locally so that angler interests are represented when decisions on access are made.

Check out five more threats facing fishing at Recycled Fish.

Thursday
Jun052014

Snakehead Numbers Decline

Maryland DNR photo Good news from the snakehead front, as the Maryland Department of Natural Resources (DNR) announced that catch and distribution of the exotic predator in the Potomac River was lower in 2013 than in 2012.

In announcing the finding from the Tidal Bass Survey, biologist Joe Love said, “The 2013 observations represent the first decrease in catch and distribution since the species was first discovered in the Potomac River (2004). It is not clear whether the cause of the decline is increased angling effort or other factors.”

But angling effort has increased considerably in recent years, aided by initiatives from both DNR and the U.S. Fish and Wildlife Service.

Additionally, the state is providing more incentive for catch and harvest of snakeheads by instituting a state record program and including an invasive species category for awards in the Maryland Fishing Challenge.

Not all the news regarding snakeheads is good, however, as two adults were captured by electrofishing for the first time ever in the Wicomico River. Anglers had reported catching them there as early as 2011.

“It appears that it takes two years between angling reporting and collection by Maryland DNR’s Tidal Bass Surveys,” Love said.

Additionally, adult snakeheads were collected from the Patuxent, in numbers similar to 2012.

“Based on suitable habitat for northern snakehead and the population estimate, we calculated that there were about five per acre of suitable habitat,” the biologist explained. “Reports for Little Hunting Creek and Anacostia River ranged from four to nine northern snakehead per acre.”

The invasive fish also was collected “in relatively small numbers” from the Rappahannock, Rohde, Blackwater, and Nanticoke Rivers.

A small snakehead was captured in a trap from a ditched area that connects the Blackwater to the Little Choptank. This suggests that the fish could use this pathway to also colonize the latter, the biologist said.

Wednesday
May282014

How About Hippos?

If you think that we’ve made a mess of our lands and waters through intentional and unintentional import of exotic plants and animals, you are correct. For example, we now spend billions of dollars annually to control and mitigate the damage done by just four recently introduced species: bighead carp, silver carp, quagga mussel, and zebra mussel.

And in attempts to minimize problems, the government often has made them worse. During the 1940s, the state of Louisiana touted the South American nutria as a way to control water hyacinth, a fast-growing exotic that was crowding out native vegetation in wetlands. Today, the nutria is eating away those same wetlands, contributing to saltwater intrusion and coastal erosion.

In the early 1960s, the states of Alabama and Arkansas allowed import of grass carp to control aquatic vegetation in aquaculture ponds. By 1970, escapees had established populations in the Missouri and Mississippi Rivers. Today, these troublesome grazers are established in at least nine states and have been sighted in more than 40. Ask just about any bass angler, and he will tell you that the grass carp is public enemy No. 1.

And speaking of carp, we have the federal government to thank for one of the worst management decisions ever in regard to our fisheries. In 1877, the U.S. Commission of Fish and Fisheries began intensively cultivating and stocking common carp. In fairness, it was prompted to do so both by public pressure and by overharvest of native fish stocks. By the turn of the century, however, it already was regarded as a nuisance.

“Moreover, their rapid spread appeared to threaten both water quality and native species, as commissioners nationwide noted a deterioration of formerly clear and fertile lakes and waterways upon the arrival of carp,” says the National Park Service.

But you don’t know the half of it. Actually, things could be worse. Much worse. Instead of nutria eating away those Louisiana wetlands, we could have hippos. And who’s to say that these massive “water horses” which can weigh up to 4 tons and eat up to 100 pounds of vegetation a day, wouldn’t have spread east, west, and north?

They are “relatively tolerant of cold conditions,” says the Glen Oak Zoo, which also points out that “many individuals live to 40 years.”

Oh yeah, they also are generally believed to have killed more people in their native Africa than another animal, including lions and crocodiles.

All things considered, I’ll take the nutria, thank you. It tops out at about 12 pounds and is not as likely to charge me at the launch ramp.

But in 1910, Frederick Russell Burnham, a famed American scout and world adventurer, proposed replacing our nation’s depleted wildlife population --- we had hunted deer, turkey, and buffalo nearly to extinction --- with animals that he had encountered in southern Africa.

His proposal lined up nicely with the search for a solution to the growing problem of water hyacinths in Louisiana waters, as well as America’s need for more meat. Writing about this little known piece of American history, Jon Mooallem in American Hippopotamus, says that Rep. of Robert Foligny of New Iberia “liked to plug up problems with big solutions.”

Thus, Foligny introduced H.R. 23261, also known as the “Hippo Bill,” to “appropriate $250,000 for the importation of useful new animals into the United States.” The Washington Post assured readers that they would see shipments of hippos within a few years.

Fortunately for all us, a boatload of hippos never docked in New Orleans. But it wasn’t because of the unexpected discovery of good judgment in Congress. Rather, one representative said that the beasts should not be introduced because unscrupulous hunters would sneak onto the farms and hunt them for trophies.

Yeah, that’s the reason not to import aggressive animals that boast 20-inch teeth and can run at speeds of more than 20 miles per hour.

What turned the tide, though, was that the Department of Agriculture decided to transform swamps and other undeveloped areas into agricultural land to grow more beef cattle.

Thank goodness. Otherwise, we might we watching “Hippo Die-Nasty” instead of “Duck Dynasty” on television.

(This column was published originally in B.A.S.S. Times.)

Monday
May262014

Zebra Mussels Benefit Lakefront Property Owners

The damage done to fisheries and water supply infrastructures by zebra mussels has been documented for decades.

But now one researcher has discovered that these exotic shellfish are benefiting a few lucky waterfront property owners, even as they wreak havoc on ecosystems.

“We find that property values generally are higher on lakes with zebra mussels,” said Martin Meder, a University of Wisconsin economics student who decided to analyze state data for 400 lakes.

With the assistance of Marianne Johnson, a College of Business economics professor, he looked at property assessments for sale of houses on lakes known to be infested with zebra mussels.

Meder added that his research doesn’t address the causation, but “with statistical certainty, I can say that zebra mussels are associated with an approximately 10 percent increase in lakefront property prices.”

He theorized that the increased water clarity that comes with a zebra mussel infestation is one reason for the increase.

And, he added, “Some research has shown that they (zebra mussels) disadvantage some unpopular fish species. They blanket the bottom of the lake bed so carp can’t feed . . .

“They also seem to be advantageous to fish species that people like, like smallmouth bass.”

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.)