A collaborative effort between fishermen and scientists to obtain conclusive data about the effect spraying for Brown Tail Moths has on Maine’s lobster population was thwarted this winter due to equipment failure at the Department of Marine Resources (DMR) in Boothbay. The problem occurred when a filter system broke down in tanks holding 100 lobsters that were part of the research project. While the lab waited for installation of a new filter, unfiltered sea water clogged the circulating system and the tanks ran dry overnight, causing the demise of 95 percent of the lobsters.

Even so, Patrice Farrey, executive director of the Maine Lobstermen’s Association, says she feels the experiment produced important positive results because of the “historically unprecedented” cooperative effort between fishermen and scientists at DMR. “Carl Wilson (a scientist at DMR) gave the experiment priority despite not having funding or staff for it,” she says. “He bent over backwards to get it going because he knew it was important to the fishermen, and they appreciate his willingness to work with them, to listen and take their concerns seriously.”

Fishermen and Wilson had placed juvenile and fourth stage lobsters in cages in Casco Bay next to areas that would be expected to have runoff from spraying for Brown Tail Moths in towns abutting the bay. The experiment included fourth stage lobsters to determine if these younger, more sensitive lobsters would be affected. Wilson hoped to observe them through several molts. He says that previous experiments with juvenile lobsters placed in spray areas have not shown any discernible difference in their ability to grow new shells.

Wilson says that since so many of the control lobsters were lost in the tank failure, there could not be any conclusive evidence from the experiment. He still needs to correlate data from cards which were placed in the water near spray sites to measure if any spray drifted beyond the 150 foot buffer zone along the coast where spraying is not permitted. Although this data will be of interest, he cautions that it also will not be conclusive since droplets on the cards will not be analyzed by a specialized lab to determine their chemical makeup – if they are pesticide or something else. However, he notes that he and fishermen were on the spot collecting cards immediately after spraying was completed, and says that therefore the cards should give some indication of drift.

A second experiment, conducted by Brian Tarbox, a lobsterman who is an adjunct professor teaching fishery science and aquaculture techniques in the Marine Science Department of Southern Maine Technical College, also fell prey to equipment failure.

On May 20 of 2002, Tarbox and his colleagues put 20 fifth and sixth stage lobsters raised at SMTC in a 100 ml jar and placed them in an area where Dimilin was being sprayed by a plane. They returned these young lobsters, which were just past the larval stage, to the lab. He says they appeared to be healthy, ate well and successfully molted about four weeks later. However, between July 4 and the end of the month, clusters of the treated lobsters began to die, whereas at the same time, control lobsters that had not been exposed to Dimilin had shown random, smaller mortalities.

Tarbox is reluctant to make too much of these findings because by September 12, all of the lobsters had died from stress caused by high water temperatures. “Near the end of July, temperatures in the lab skyrocketed,” he explains, “and the cooling systems were overrun. We started losing everything. By Sept. 12, everything had died. That the treated lobsters tended to die in clusters before the temperature rose is intriguing, but it’s hard to draw firm conclusions.”

Coastal towns infested by Brown Tail Moth populations, which include Brunswick, Harpswell, Freeport, Yarmouth, Cumberland and Falmouth, have been debating whether or not they will fund spray programs this year. Dick Bradbury, an entomologist with the Maine Forest Service, has not been recommending that towns adopt an aerial program. One reason, he says, is that last year, so many people who live along the coast exercised their option not to have their properties sprayed that it weakened the effectiveness of the spray program. Also, since the moths have moved inland where the oak trees they favor are more scattered and houses are spread out, it is difficult to treat those properties on an equal basis with more dense coastal property.

By mid February, all towns but Yarmouth had decided not to spray, and Yarmouth councilors were still debating the issue. “It’s hard for the councils,” Bradbury observed. “They may want to say no, but they also want to serve the needs of the residents.”

Residents can choose to hire an arborist licensed by the Maine Board of Pesticide Control to spray their property. The chemical can be applied up to the high water mark, but arborists are required to keep it out of the water. Individual spraying causes continued concern among lobstermen, who fear that Dimilin, which Wilson explains is a chitin inhibitor and could prevent lobsters from forming shells, may harm the lobster population.

Bradbury says Dimilin ties up well with organic matter and tends to stay put. “I don’t worry much at all about the stuff washing into the water,” he says. “As long as it is applied carefully, it should be a reasonably low risk exercise.”

The best case scenario, he adds, would be a widespread die-off of Brown Tail Moths due to this winter’s cold temperatures. “Right now, even if you bring them into a warm place,” he says, “they remain dormant and it’s hard to tell if they’re dead or alive. In March, we’ll be able to go out and collect a bunch and see if there are mortalities. If so, we could tell people to stop spraying.”

Residents in moth-infested areas can obtain information on preventive measures at their town halls or visit the website to be found at .