Week of February 9, 2009

Updated 2/12

Exotic fish pose threat to native species in Everglades

By Curtis Morgan, Miami Herald

The small pond six miles deep in Everglades National Park suddenly began bubbling like a pot aboil -- a telltale sign of air-slurping walking catfish.

Dave Hallac, the park's chief biologist, dipped a net into the muddy commotion and hauled up a mess of wriggling slime so hefty it surprised even him. He counted out 56 fish from a single scoop.

Walking catfish, along with other species originally imported for somebody's tank or table, outnumbered natives in this shallow, shady bayhead by an unhealthy margin. Unlike giant python, the Glades' most notorious invader, these dinky denizens don't draw attention to their presence by, say, swallowing an alligator and exploding. But for park scientists, their spread is no small concern.

''This is a problem that is 10 times worse than the python, but it's all under water, so nobody knows about it,'' Hallac said. Link

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Insect killing Pennsylvania's hemlocks

By Dan DiPaola, Daily American

RICHLAND (PA) TOWNSHIP - The hemlock population around the Quemahoning Reservoir is under attack by an invasive insect that could wipe out the tree within four years, according to Cambria Somerset Authority officials.

A harvester working in a large stand of hemlock along Que Dam Road found the hemlock woolly adelgid, an aphid-like insect from Asia, in downed trees in November, said manager Thomas Kakabar.

“We've been keeping an eye out for it and now we have it,” he said. “It's going to claim most of the hemlock in Pennsylvania.”

The small soft-bodied insect feeds on young branches, which results in premature needle drop and branch dieback, according to the state Department of Conservation and Natural Resources.

The insect was first reported in the state in the late 1960s and has been reported in 44 counties as of 2005, according to the site. “East to west, it's been moving this way for a while,” said authority Chairman James Greco. Link

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Invest in restoration, not Asian oysters

The Virginian-Pilot

EVERYONE AGREES on the need to restore the Chesapeake Bay's oyster population, both for the ecological effects and commercial possibilities. The disagreement - raging for years now - is over what restoration should look like and what its goal should be.

Maryland, Virginia and federal officials are now considering whether to introduce a foreign oyster species into the Bay in hopes of saving an industry that has been dying since the parasitic diseases Dermo and MSX arrived in the watershed.

Many of the remaining seafood processors want an oyster that will allow them to stay in business and provide jobs. The Asian oyster has shown significant potential. Watermen are more divided; some are already growing native oysters they fear would be crowded out by a foreign species.

Aside from the commercial considerations, there are ecological ones. The decline of the Bay's oyster population has coincided with the decline in its water quality. Restoring any oyster - along with the menhaden and other struggling species - could do much to make the Bay healthier.

The Bay's primary environmental watchdogs, after years of relative neutrality on the subject, are now lobbying to keep out the Asian oyster, preferring instead a greater effort to restore the native species. There have been encouraging signs, particularly in the Lynnhaven watershed, that the native species have potential to rebound if enough effort is put into restoration. Link

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Economics of Invasive Species

Oregon Invasive Species Council. Prepared for the Oregon Invasive Species Council by Oregon State University. Link

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Beach Vitex Task Force symposium

The Carolinas Beach Vitex Task Force will hold its annual symposium on Friday, March 13 at 10:00 a.m. at the North Carolina Aquarium at Fort Fisher, 900 Loggerhead Rd., Kure Beach, NC (near Wilmington). The symposium is open to the public. Link

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Tennessee Governor Proclaims Invasive Weed Awareness Week

Governor Phil Bredesen has issued a state proclamation declaring Feb 22-28, 2009, as Invasive Weed Awareness Week (IWAW) in Tennessee in conjunction with the 10th Annual National Weeds Awareness Week in Washington, D.C. The Tennessee Exotic Pest Plant Council (TN-EPPC), an all-volunteer, nonprofit organization, is working closely with various local, state and federal organizations and agencies to promote public education on the harmful impacts of nonnative, invasive plant species through several "pest plant removal events" around the state. Link

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Waccabuc Cove, NY, Brazilian water-weed removal plan presented

By Matt Dalen, LewisboroLedger.com

Four months after discovering a highly invasive aquatic plant in Lake Waccabuc, the Three Lakes Council is planning drastic measures to remove it. A plan presented at the Tuesday, Jan. 27, meeting of the Planning Board would essentially remove the top layer of the lake bottom over an area of nearly two acres, in hopes of capturing every fragment of Egeria densa, also known as Brazilian waterweed or Brazilian elodea. The plan would cover the entirety of Waccabuc Cove, a small cove on the north shore of the lake. So far, the plant has only been found in that cove.

“I want to start this as soon as possible,” said Janet Andersen, who represented the council before the board. “If this thing is out somewhere else, the game’s over.”

The proposal is likely to go to a public hearing in March before the Planning Board rules on the permit.

Because only male specimens of Brazilian elodea have been brought to the United States, the weed cannot reproduce with seeds. However, a fragment of the weed can grow into a full plant, and it grows at an extremely fast pace, which makes it one of the worst aquatic invasive species.

“This is something which, certainly, it appears we have one attempt to hopefully eradicate,” said town wetlands consultant Bruce Barber. “I’m not sure you have a real good second attempt at it if it starts to spread out in the lake area. We want to make sure we get this right the first time.”

The proposal would close off the cove and use “suction harvesting” to suck the lake bottom into containers, which would then be disposed of. It’s the hope of the council that this type of suction would be able to capture every fragment of the plant in the cove. This may be possible because the weed appears to be contained to just the cove, and wind and water currents both run into the cove, potentially isolating it.

Ms. Andersen said that an alternative — aquatic herbicide — had been considered, but that had run into several problems, the largest of which was residents of the lake community who use the lake for drinking water. At least 14 homes get their water supplies from the lake, according to Ms. Andersen, several of whom live on that cove. Aquatic herbicide would cut off the use of the water to those homes for at least two months, not only for drinking but also for showering and other uses.

The suction harvesting plan, which requires state approval in addition to town approval because the state owns the lake bottom, would cost at a minimum about $15,000 per acre just for the suction itself, Ms. Andersen said. Additional costs, which have not been measured, would be incurred for obtaining a 400-foot net to block off the cove during the work and capture any fragments of the weed that drifted away, educating the public on what the work entails, and disposing of the material harvested from the bottom of the lake. The money would likely be obtained by the council through a fund-raiser, Ms. Andersen said.

Assuming all of the permits are received and the council can find an experienced manager to oversee the harvesting, the hope is to complete the work before the Fourth of July and before extensive boat traffic begins on the lake.

Board members asked about the potential impact on the cove’s ecosystem. Ms. Andersen said that previous experience had shown that, after this kind of project, water plants repopulated the area quickly. She also said that, while a small number of fish might be caught in the suction harvest, they would likely flee from the commotion, and that there were no endangered or threatened fish in the lake. Link

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New aquatic invaders info available at the Central NY Boat Show

By David Figura, The Post-Standard

Boaters interested in how they can prevent the spread of fish diseases and aquatic invaders such as zebra mussels and water chestnuts that disrupt the food chain, clog waterways and cost millions of dollars annually in control measures across the country can check out a new exhibit this week at the CNY Boat Show at the NYS Fairgrounds.

The show begins at 1 p.m. Wednesday and continues through Sunday.

The Finger Lakes Partnership for Regional Invasive Species Management will be providing fact sheets and other resources for dealing with invasive species on the Great Lakes, inland waters (streams, ponds and lakes) at a booth in the Toyota Building.

The boat show this year will feature more than 500 power and sail boats, yachts, water recreation equipment and marine accessories on display. The show runs from 1 to 9 p.m. Wednesday, Thursday and Friday; 10 a.m. to 9 p.m. Saturday and 10 a.m. to 5 p.m. Sunday. Cost is $9 per person; children under 12 free. Free parking. Link

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To battle phragmites, Assateague calls in the torches

By Charlene Polk, DelmarvaNow.com

ASSATEAGUE ISLAND, DELAWARE -- The National Park Service intends to use controlled burns on Assateague Island to help control the spread of the invasive plant phragmites next month.

The park service plans to burn about 200 acres during one week sometime between March 10 and April 1 to remove the above-ground remains of Phragmites australis (common reed) that have been sprayed with herbicide. It will be the first time the park's staff has chosen to fight the rapacious cattail-like plant with fire.

"The goal is to reduce the biomass, the phragmites deadened down by aerial spraying," said Ted Morlock, chief ranger at Assateague Island National Seashore. "This will help re-vegetate areas." Link

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Invasive insects in our woods

7 p.m. Tuesday, Feb. 24, at the Thayer Memorial Library, Lancaster, MA. The news is full of stories about insects with exotic-sounding names we never heard about years ago — Emerald ash borer, Hemlock woolly adelgid, and right here in Worcester, the Asian long-horned beetle. Who invited these pests in and how are they able to cause so much damage once they arrive? Program presenter Laura Marx is the forest ecologist for the Nature Conservancy’s Massachusetts Chapter and an adjunct professor of environmental biology at Westfield State College. Laura will tell stories of invasive insects and describe how all of us can have a part in controlling these insects. Everyone will leave with the information needed to be a set of “eyes on the ground” and a better understanding of how important it is to work to prevent these outbreaks in the first place. Age 10 through adult. Link

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