Fishermen who on Tuesday and yesterday applied for permits to use their boats on Prettyboy and Liberty reservoirs this season will not be issued permits until a potential problem with zebra mussels is investigated, an official of the Baltimore City Department of Public Works said yesterday.
"There is a temporary delay in issuing boat permits," said public information officer James Kapplin. "We are concerned about zebra mussels getting into the reservoirs."
Zebra mussels are a European strain of shellfish that has infested the Great Lakes, some Midwestern rivers, the Hudson River and the Susquehanna River. Department of Natural Resources biologists are trying to determine whether the mussel also has established itself in areas of the Chesapeake Bay.
Zebra mussels, which presumably were introduced to the Great Lakes by ocean-going ships blowing freshwater ballast taken on in Europe, apparently have no natural enemies in North American waters.
The foremost danger posed by the zebra mussel is its infinity for colonizing intakes in reservoirs and greatly reducing the efficiency of water supply operations.
Prettyboy and Liberty reservoirs, as well as Loch Raven Reservoir, provide water for 1.5 million people in the Baltimore area, Kapplin said.
Loch Raven will not be closed to fishing, Kapplin said, but the public ramp will be closed and only the Fishing Center rental boats will be allowed on the reservoir for the time being. Kapplin said zebra mussel contamination of rental boats can be ruled out because the craft have not been exposed to other waters.
The Department of Public Works is concerned that boats that have been used in other waters, such as the Susquehanna River, might pose the danger of contamination. Fishermen counter, however, that reservoir rigs are of little use elsewhere and should present no danger.
As an example of how zebra mussels have been transported from infested waters such as the Great Lakes, Kapplin said that the Ohio River and the Illinois River now have populations of these mussels even though there is no direct connection with the Great Lakes.
"A town in Michigan, Monroe," Kapplin said, "had its water supply contaminated, and they spent $500,000 last year to keep the facility operating properly."
The Department of Public Works, which operates Liberty, Prettyboy and Loch Raven reservoirs, yesterday sent a staff member to Toronto to attend an international conference on the zebra mussel problem.
There are chemical treatments that might check zebra mussel populations, but, Kapplin said, these can produce foul tasting or smelly water.
"There seems to be no magic medicine, however," Kapplin said. "While we are not certain that we have them yet, we do want to be certain that we take every precaution."