In Somerset, Mother Nature Is Mosquito Control
The Daily Times
DEAL ISLAND, Md. (AP) — A complex geography system in the marshland near Deal Island explains much about the great outdoors humans from Delaware to Virginia enjoy in summer.
To say the lower Eastern Shore mosquito population is heading toward to extinction would be an exaggeration. But the Open Marsh Water Management project established in 1984 across Somerset County marshland has cut the population of the blood-sucking species on almost 400 acres in the Deal Island Wildlife Management Area.
That was not the case three decades ago, environmental scientist Daniel Schamberger told a group of ecology students at Frostburg University.
In the mid-1970s, the Maryland Department of Agriculture launched the open marsh project as a management tool to control mosquitoes in coastal salt marshes such as in Deal Island, building ditch systems and ponds as habitats for fish species as sheepshead minnows, Atlantic silversides, American eel and more. The ditch and pond systems are a sustaining habitat for fish that fed on mosquito larvae.
The man-helped ecological system rids the region of mosquito larvae and keeps fish wildlife plentiful and happy, he said.
“The program is designed to control mosquitoes and enhance habitat for wildlife,” Schamberger told a group of about 10 students who toured several acres of the Deal Island Wildlife Management Area. They walked the marshes, netted mosquito fish, common killifish, banded killifish, Atlantic silversides and four-spine sticklebacks, to name a few.
Students measured the salinity in the salt ponds. They collected marsh grasses including spartina patens, or salt meadow hay; distichlis spicata, or salt grass; and scirpus olneyi, or olneyi three-square.
Not a mosquito was in sight.
“Essentially, we created wildlife ponds on the marsh that are utilized by blue crabs and fish,” Schamberger said. “Then salt marshes will flood with a full moon tide or storm tide, triggering mosquito eggs to hatch out. Then, fish leave the ponds — there is excess water that allows them to — and feed on the mosquito larvae.
“This slowly drives down the mosquito population,” he said. “Then they return to the pond and stay until the next flood in a couple of weeks.”
Mosquitoes can travel up to 20 miles, and the Deal Island project means fewer of them as far as Princess Anne, Salisbury and other towns within the flying range. Before the preventative system, “there was marsh with mosquitoes and no fish,” because water was too shallow to attract fish wildlife with an appetite for larvae.
“Before the `70s, either fish didn’t come into the marsh, but instead, found refuge in depressions so they don’t dry out,” said Schamberger, who also studied saltwater marshes as a student at Frostburg in the 1990s. “Talk to the locals about mosquitoes, and they’ll likely tell you that mosquitoes are quite bad still, but imagine adding several 100 acres of them to the population.
“We would have to spray more insecticide to reduce the population,” he said. “Operational costs would be higher.”
Frostburg biology professor William Pegg, on his 41st trip to the Deal Island management area, noticed there were no nutria scrubbing about the marsh. A state agricultural control project captured many of the root-eating rodents that migrated to the lower shore years ago from regions around the Gulf of Mexico, were trapped and removed.
“Nutria and muskrats eat through the drain ponds,” he said, killing off habitat.
In all, 23,000 acres of saltwater marshes are part of the OMWM project established across the lower shore and in Dorchester County between 1976 and 1992. The Deal Island project was completed in 1984, and includes 76 ponds across 376 acres of marshland.
“We’ve sprayed about three or four times since the `80s,” Schamberger said, referring to insecticides for mosquitoes. “During drought times, when fish aren’t plentiful.”
Jake Blakely, a Frostburg student studying wildlife and fisheries, expected an onslaught of mosquitoes and sprayed himself with mosquito repellent before drugging through the stalk-ey, muddy marsh.
“I thought I’d be eaten, and I put on all this bug spray,” he said. “But there are no bugs on me.”
Ericka Randolph, a student from the Baltimore area, appreciated the hands-on experience touching the variety of fish in the ponds and marsh grasses. She also gained an appreciation of nature.
“This is cool,” she said. “Everybody should be exposed. Most people are scared of things they don’t understand.”
Information from: The Daily Times of Salisbury, Md., http://www.delmarvanow.com/
(Copyright 2013 by The Associated Press. All Rights Reserved.)