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Entries in invasive species (223)

Thursday
Oct292015

National Policy Needed to Help Stop Spread of Grass Carp

This grass carp was illegally stocked in a lake where it wasn't needed, and the health of the fishery has suffered as a consequence. Photo by Robert Montgomery

Although grass carp have been found in every one of the Great Lakes except Superior, resource managers don’t believe that the exotic fish have established a self-sustaining population.

But the Mississippi Interstate Resource Association (MICRA) recently warned that “state grass carp regulations are varied and inconsistent, and a national policy strategy is needed to effectively minimize the risks of additional fertile and sterile grass carp introductions into the Great Lakes.”

MICRA reached that conclusion as result of a study funded by the U.S. Fish and Wildlife Service (FWS) to look at grass carp use, production, and regulations. It also made recommendations to help minimize risk not only to the Great Lakes, but other waters not yet infested by unintentional introductions of this aquatic invader.

Those recommendations include the following:

  • Production, shipment, stocking, import, and export of diploid (fertile) grass carp should be prohibited except by licensed facilities.
  • States that allow production of triploid (sterile) grass should develop a set of minimum standards, permit requirements, and recordkeeping for diploid broodstock.
  • States that allow importation of triploid carp should adopt consistent regulations that allow only FWS-certified fish.  Also, increase random inspections and enforcement of regulations in these states.
  • FWS should work with states, producers, and other partners to develop testing procedures for quality controls and law enforcement in support of random inspections.

Grass carp, a species of Asian carp, were first imported into the U.S. in 1963 as a tool to manage nuisance aquatic vegetation, including exotic hydrilla, in ponds and impoundments. But flooding allowed many to escape into rivers and streams and, by 1970, they were reported in the Mississippi River basin.

Sunday
Oct182015

Banning Fishing Won't Save Coral in Biscayne National Park

Too many in this country, especially anglers, fail to recognize that the anti-fishing movement is strong and going stronger, not only in private organizations such as PETA, but in federal government. Right now, anti-fishing elements in both groups are strategizing together about how to establish National Marine Monuments that would prohibit recreational fishing off the New England coast

The National Park Service (NPS)  already has closed portions of Cape Hatteras National Seashore, and now it's going after a recreational fishing ban on part of Florida's Biscayne National Park, under the pretense of protecting coral.

 But because its decisions affect just one part of the country at a time, outrage regarding its actions usually is limited to those personally affected by the loss of access and the fishing industry in general, which tries its best to awaken anglers to this threat.

U.S. Rep. Ileana Ros-Lehtinen exposed how anti-fishing proponents have corrupted NPS management in her recent critique of its proposal.

"Putting a no-fishing zone at the forefront of Biscayne’s coral-protection strategy would seem to suggest that NPS believes fishing is the primary threat to our reefs," she said.

"But scientists have determined that poor water quality and periodic extreme water temperatures are responsible for most coral losses in Biscayne over the last two decades. Furthermore, overfishing is just one of five major threats to Biscayne’s coral reefs that NPS has identified, including reduced freshwater flows into Biscayne Bay, invasive species, water quality/pollution and climate change.

"Knowing this, how can NPS propose that eliminating fishing in 7 percent of park waters will vastly improve the state of park reefs?"

She also correctly contrasts that political move to impose an preservationist ideology with how NPS managers at Everglades National Park properly developed a management.

" Everglades’ GMP (general management plan) has gone through the same tortured process that Biscayne’s has, yet when the final plan was recently released, it was rightly praised by fishermen and environmental groups alike because it was grounded in a consensus-based plan that balanced ecological protection and public access. The plan vastly expands pole/troll zones across Florida Bay to protect vital seagrass beds from boat motors while allowing folks to enjoy fishing and boating in their public waters via dozens of new, marked access routes."

That plan, she correctly pointed out, supports both fish habitat and fishing.

"In Biscayne, the plan lays out a false choice between fish habitat or fishing," she said. "It’s not too late for the Park Service to develop a GMP for Biscayne that can actually deliver the conservation benefits it’s designed to provide, and do so with the support of all stakeholders in our community — the type of GMP that neighboring Everglades National Park recently proposed."

Thursday
Oct082015

Snakeheads Growing Bigger, Spreading Farther Up the Potomac

Dan Moon caught this monster snakehead on a Booyah spinnerbait.

As state and federal resource managers revealed that the northern snakehead has spread into the Upper Potomac River, a local angler provided yet more evidence that these exotic predatory fish grow larger here than anywhere else in the world. That's a potential double whammy for bass and other native species.

"Part of the reason we should be worried about it is we don't really know what the impacts are going to be," said Joe Love, tidal bass program manager for the Maryland Department of Natural Resources (MDNR). "We do know that, in some cases, invasive species cost millions of dollars in damage to the ecosystem."

With the population of snakeheads in the tidal Potomac now an estimated 20,000, one concern  is that  aggressive snakeheads will outcompete bass for food, a fear that is heighted by the fact that they are growing to world-record proportions. In late June, Dan Moon boated the latest giant, which weighed 18.8 pounds on an uncertified scale.  The official world record checked in at 17-12, and was caught last year within two miles of where Moon caught his fish.

With both adult snakeheads and fry confirmed in the C&O canal above Great Falls, it seems almost certain that the invaders will spread up the non-tidal Potomac, as well as into its tributaries.

"Eradication is not possible once these fish become established in an open river system such as the Potomac," said MDNR biologist John Mullican. "We expect that these fish will eventually become a permanent part of the Upper Potomac fish community. Confronting snakeheads in the canal system is the best way to mitigate their emigration into the Upper Potomac.

Consequently, Maryland is working with the U.S. Fish and Wildlife Service and the National Park Service to develop control strategies.

MDNR emphasized that the snakehead can be caught legally in any season and at any size. "We'd like it to be harvested if anyone catches it," Love said. "We'd like it if they took it home and possibly ate it. Anglers and archers enjoy fishing for them, which is great. And they enjoy eating them, which is great."

Monday
Sep212015

Hydrilla Creeps Closer to Great Lakes

Hydrilla is creeping ever closer to Lake Erie, the warmest and shallowest of the Great Lakes. Most recently, it has been found about 20 miles away in Lake Pymatuning, a 17,000 -acre impoundment on the Ohio/Pennsylvania border.

"It is a serious situation," said Brian Pilarcik of the Crawford County Conservation District. "It can grow very fast, almost an inch a day and forms large, dense masses that can and will impact water sports and will have a negative impact on tourism in the county.

"We are very concerned that the plant could eventually reach Lake Erie."

An environmental educator at Pymatuning, Linda Armstrong added, "The lakes here get quite a bit of use and people will go from one to another, so it is critical to clean all equipment as well as boats."

Already Pennsylvania resource managers have talked with their counterparts in Florida about the discovery, with the latter promising assistance in containing the invasive plant.

Long a problem for many fisheries in the South, hydrilla was first reported in Pennsylvania during the mid 1990s, according to Pennsylvania Sea Grant (PSG).  It's also now established in Bucks County and the Schuylkill River in Philadelphia. The next closest infestation to Pymatuning is Lake Arthur, about 60 miles to the south.

"Hydrilla is a federal noxious weed that continues to spread to new regions in the United States," PSG said. "It is unknown exactly where hydrilla originated, but Asia, Africa, and Australia are all mentioned in the literature as native ranges.

"Currently, Antarctica is the only continent without records of hydrilla."

Monday
Sep072015

Asian Carp Spawn Raises Threat for Barkley, Kentucky Lake Sport Fisheries

Can an Asian carp invasion destroy a world-class sport fishery? We're about to find out. And, no, it won't be in the Great Lakes.

Ground Zero will be Kentucky and Barkley Lakes, where anglers and commercial fishermen now are seeing millions and millions of young-of-the year silver carp.

Commercial fisherman Ben Duncan sent me these photos that he recently took at Boswell Bay, where he caught about 500 of them.

"I've seen similar schools in Cypress Bay, Eagle Creek, and Blood River," he said. "My conjecture is this year's mid-summer flood has made the 2015 spawn one for the record books."

And Paul Rister, a Kentucky fisheries biologist, confirmed that assessment. "Yes, we are aware of the tremendous spawn of Asian carp in the tailwaters and lakes this past spring," he said, adding that the state recently implemented a nickel a pound subsidy to encourage commercial harvest.

He also said that the numbers of carp likely will be far more than commercial fishermen can harvest, especially since nets can capture only larger specimens.

"So, what is the answer?" he continued. "There is not one yet. The good news is that it is still very unlikely that the carp have impacted sport fish in the lakes."

They may have displaced them, though, meaning anglers might find the fishing tougher as they are forced to fish new areas. Also, with so much forage, bass and crappie might be more difficult to catch on artificial baits--- at least immediately after the carp spawn. But within a few months, the fast-growing carp are too large for sport fish to eat.

Those impacts are short term. What's going to happen during the next year? Or five? Will the invasion overwhelm the sport fishery as carp occupy so much water that there's no room for other species?  That's happened in portions of major rivers, including the Missouri and Illinois.

Will commercial fishing contain carp numbers? Will scientists develop a chemical or biological control?

We will just have to wait and see.