The Gulf of Maine Times: Vol. 7 Num. 4

Maine to lose dams, gain fish

The announcement in October of an agreement between a coalition of conservationists and the power company that operates dams on Maine’s largest river continues to be hailed as one of the most creative and historic river restoration compromises in U.S. history. The agreement, many advocates believe, stands a good chance of saving the struggling Atlantic salmon, along with a dozen other species of fading fish.

Under the agreement, two dams on the Penobscot River are to be torn down, the Veazie Dam above Bangor and the Great Works Dam in Old Town, thus removing important barriers to fish returning from the ocean to the river to spawn. The Howland Dam on the Piscataquis River will be decommissioned, and a bypass will be built around the structure so the salmon can pass.

In exchange, the coalition will pay the power company, the PPL Corporation, about $25 million. PPL will be able to increase its power generation on six other dams on the Penobscot and one tributary, recapturing about 90 percent of the power it will lose when the dams are demolished. The coalition also agreed to drop legal challenges to the relicensing of the dams by the federal government.

For thousands of years sea-run fish migrations defined the Penobscot. But for decades their numbers have been dwindling, despite efforts to bring them back by banning salmon fishing, stocking the rivers with millions of fish and cleaning up pollution.

The dams were first installed in the lower Penobscot more than 150 years ago, blocking fish migrations and gradually degrading water quality and wildlife diversity. For more than a century, the Penobscot Indians have been unable to exercise their tribal fishing rights because the river is virtually devoid of native sea-run fish above Veazie Dam. This agreement, Chief Barry Dana said, “will restore our ability to obtain our sustenance, culture and identity from the river that bears our name.”

At least two years of behind-the-scenes negotiations led to the conceptual agreement between PPL and a long list of parties that include the state and federal governments, conservation groups and the Penobscot Nation tribe. Along with restoring fish and wildlife and improving water quality, those involved in the agreement predict the agreement will help foster economic revitalization of communities along the river, drawing recreational fishermen and kayakers.

The buzz in Cape Cod

It seemed inevitable. Last summer, mosquitoes in Cape Cod tested positive for the West Nile virus, Eastern equine encephalitis, and several birds across the Cape came up dead from West Nile as well. Now mosquito control experts in Massachusetts are trying to find innovative ways to cut down on the population of these potentially disease-harboring insects. Mosquito-eating fish may be a big help.

Scientists at the Marine Biological Laboratory in Woods Hole are collaborating with the state’s Cape Cod Mosquito Control Project to develop a manual for cranberry growers to raise large numbers of the banded sunfish, Ennecantus obesus, in often-fallow cranberry bogs. The native fish has an insatiable appetite for mosquito larvae, which typically live at the surface of stagnant water bodies. The long-term plan is for cranberry growers to sell the fish to hobbyists and gardeners with backyard ponds and to convince the state to stock some in larger bodies of water.

The glacial deposit that formed the Cape created more than 3,500 potential freshwater mosquito habitats, says Gabrielle Sakolsky, an entomologist with the Cape Cod Mosquito Control Project. Add to that a boom in water garden ponds and you have an area replete with prime mosquito breeding grounds.

In combating the mosquitos, the state agency faces an uphill battle. The bacteria that kills mosquito larvae must be reapplied every 12 to 14 days to larval habitats during the summer. This method of controlling mosquitoes, though effective, can be tough going. “When you apply that bacteria to a swamp, you need a crew to apply it and walk through the whole site,” Sakolsky says. Individual swamps range from less than an acre to about 20 acres. “A major advantage of using fish,” she says, “is that you can release them at one site, and they go find the problem.”

Scientists working on the sunfish plan have considered the potential impacts of introducing large numbers of captive-bred fish into the larger environment, even though they are native to the Cape and other areas in the Northeast.

The biggest concern is whether the introduced sunfish might escape their intended waters, overpopulate and wreak havoc on ecosystems. That’s unlikely, says Bill Mebane of the Marine Biological Laboratory (MBL). He explains that the sunfish require both low-mineral and highly acidic water to reproduce—water found in only a few natural settings, including cedar swamps and peat or cranberry bogs. There is little chance of the sunfish reproducing outside the acidic bogs where they will be introduced, and where they are found in small numbers today. “The chances are slim to none,” he says, that the sunfish will escape their intended habitat, swell in numbers, and compete with other species.

Even if a few sunfish were to find their way out of the cranberry bogs into waters where the project managers did not want them to go, Mebane says, the scientific consensus is that they would survive the winter, but not reproduce. The errant fish would have no heirs in their new environments, and would simply die off with time.

Large numbers of banded sunfish might also alter the ecology of the cranberry bogs where they will be reared. The MBL’s research, however, suggests that the cranberry bogs do not have many other fish to be crowded out by even large numbers of banded sunfish. Mebane says that his team pulled a 100-foot seine through flooded bogs near Wareham, and found “essentially no other fish.”

Mebane says that the banded sunfish may take some food away from other species of fish and possibly consume food other than mosquitoes. He hopes that the state will soon put some of these fish in a pond with no inlet or outlet and compare other fish populations before and after the introduction to see whether the sunfish displace, for example, local bass, by competing for food.

Big headache at Great Bog

One of the biggest challenges land trusts face is making certain the terms of a conservation easement are upheld. Typical scenarios include working with subsequent landowners to enforce restrictions on development or all-terrain vehicle use. But then there’s the story of the Great Bog in New Hampshire. Sandwiched between interstate I-95 and several local roads, the bog is an ecological treasure. In 2001, after a developer proposed to build two dozen homes in the bog, the city of Portsmouth bought 200 acres to stop the project. To ensure added protection, the Seacoast Land Trust became the conservation easement holder for the property.

But much to the trust’s chagrin, the land has for years served as a dumping ground for stolen or torched cars. “It’s by far our biggest headache,” says Danna Truslow, the trust’s president. Not only are the abandoned vehicles and motor parts and debris unsightly and hazardous to water quality and wildlife, she adds, they give the impression that the area is seedy and unsafe to walk around.

Tracking down the owners of these vehicles has not been easy. Some of the cars are burned to avoid detection and their vehicle identification numbers stripped. Apparent thrill seekers have torched cars just for fun.

But with the help of the state’s largest utility company, Public Service New Hampshire (PSNH), Portsmouth city officials and nearby landowners, the trust’s hopes of changing the image of the bog is making headway.

This past summer PSNH paid for a gate to close off the main access point large enough to drive a car through. The city is gradually blocking off other entry points. PSNH also extracted more than 14 cars from deep inside the bog that will eventually be hauled off to a recycling center.

To boost the public’s awareness, the trust has started posting signs on the property prohibiting wheeled vehicles. Truslow says an education campaign is ongoing. She adds, “We need to get the word out to the public that it’s not okay to dump cars.”

The trust is also working with PSNH to turn 43 acres of upland on the bog into grasslands. With the use of a “brontosaurus,” a rotary brush cutter mounted on an excavator, the utility company is removing non-native species such as buckthorns and Japanese barberry brought in decades ago to attract birds. In place of the invasives, the trust has dotted the upland with boxes for bluebirds and kestrals.

“We just want to make people feel comfortable being there,” Truslow says.

Radar detects pollutants

When in Halifax, Nova Scotia, watch for the green laser light beaming above Dalhousie University. The radar-like system called lidar has been measuring particles in the atmosphere to help scientists get a better understanding of climate change, ozone depletion and air quality. Just as sonar transmits sound waves in water to measure vibrations bounced off its target, lidar uses pulses of laser light to probe the atmosphere overhead. The small portion of light reflected back is measured using astronomical telescopes and sensitive detectors. The information is then analyzed by computers and used for research.

Tom Duck, a professor of physics and atmospheric science at Dalhousie, who developed the lidar with four of his students, says the technique is similar to sonar, “except that instead of pinging submarines with sound, we detect molecules in the air with a laser.”

Initially the work will examine cirrus clouds and contrail cirrus in particular. Halifax lies directly beneath a major flight corridor between North America and Europe, and the contrails that form behind commercial aircraft have the potential to induce regional climate change, Duck says.

The team will also use the “laser radar” to investigate the Earth’s stratosphere, where the ozone layer resides. Ozone depletion is particularly sensitive to the changing stratospheric temperatures. Waves occur in the atmosphere (just like on the ocean’s surface) and strongly perturb the stratospheric conditions. Duck says the inability to predict ozone depletion from year-to-year is due to a lack of understanding of atmospheric waves.