Jack Jennings, an outdoorsman, grew up catching crayfish in the streams around this popular lakeside resort area. He hasn't seen a crayfish in years.
David Hatch, a contractor, replaced an 18-year-old canvas deck on a local boathouse. Now, three years later, the new deck is deteriorating rapidly - pocked with holes that look like cigarette burns.
The contractor's wife, Sheilah, noticed that the metal window screening on their home was rotting away. She was not alone: Last spring, she says, there was such a demand for screening at the local hardware store that the owner could hardly keep it in stock.
To these citizens of the Muskoka Lakes region, these three problems have one explanation: acid rain.
In the past decade the question of acid rain - where it comes from, and what damage it does - has grown from a pet peeve of fringe environmentalists to a major topic of scientific research.
And over the past several years it has taken yet another turn - into an issue of international proportions. It has become, in the words of Canada's minister of the environment, John Roberts, ''the single most important issue or irritant'' in Canadian-American relations.
Most significantly, however, it has led Canadian diplomats in the last six months into the uncharted waters of so-called ''public diplomacy.'' In their attempts to negotiate an agreement on acid rain with the United States, they are bypassing the typical diplomatic channels. Instead, they are mounting a lobbying effort on Congress and the American public.
In a Toronto hotel last month, the youthful-looking environmental minister articulated the Canadian view to a group of American journalists. He observed:
* That acid rain, thought by a number of scientists to result when air pollutants mix with moisture in the upper atmosphere, is ''killing'' millions of lakes in eastern Canada and the northeast corner of the US, and may be damaging forest growth.
* That a growing body of evidence suggests that the worst pollutants - sulfur dioxide and nitrous oxides - are generated by coal-burning utilities and factories.
* That if acid rain does indeed come from power plants, then the worst offenders are most likely in America's industrialized Ohio Valley, which allegedly ''exports'' its pollutants northeastward for hundreds of miles along prevailing winds.
The message from the Canadians is blunt: The US should impose tough controls on its polluters, aimed at reducing the ''atmospheric loading'' of harmful compounds by 50 percent in 10 years.
''We are extraordinarily concerned,'' says Mr. Roberts, noting that the damage falls most heavily on Canada's lucrative tourist and sport-fishing businesses. The added acidity also, he says, may impede tree growth - a serious concern to the nation's forest industry, which has sales running to $24 billion per year and employs one out of every 10 Canadians. He notes that Canada has reduced its stack emissions by 25 percent in the past decade and is scheduled to cut another 25 percent.
But the message seems to be falling on deaf ears. Relations between US Secretary of the Interior James G. Watt and his Canadian counterpart are said by Canadians to be extremely poor. Canadians feel that further meetings with Anne M. Gorsuch, the director of the US Environmental Protection Agency (EPA), would be fruitless.
As a result, the Canadians have undertaken an intensive and sophisticated lobbying effort:
* They issue scientific studies, slickly printed booklets, and singing radio ads for use by US news media.
* They have played host to several carefully designed visits by US journalists and congressmen - especially those from the Northeast, which also suffers from acidified lakes.
* Their ambassador in Washington, Allan E. Gotlieb, hops across the US to tell the Canadian side, while federal and provincial ministers accept numerous invitations to speak to conferences south of the border.
* The Washington office of the Canadian Coalition on Acid Rain - officially funded by $150,000 in contributions from 39 Canadian citizens' groups but in fact supported by materials, personnel, and another $200,000 from Canadian government sources for its Toronto office - works closely with the embassy to push the issue.
"It's a landmark in the degree and intensity of involvement in the internal affairs of the United States by a foreign country,'' says James M. Friedman, a Cleveland attorney who represents utilities. A US State Department official, taking a dim view of the lobbying efforts, notes, ''We've told the Canadians that we didn't think they were helpful and could be harmful'' to bilateral negotiations.
Ambassador Gotlieb admits to ''a change in style in diplomacy.'' While noting that some sensitive issues must be negotiated between nations in secret, he says: ''You don't deal with Congress secretly - Congress is a public body.''
''I see public diplomacy as the normal condition for diplomacy between our two countries,'' he says, ''We are not two societies that deal simply through the channels of two governments.''
Out in America's industrial heartland - the region including Ohio, Kentucky, Indiana, Missouri, Tennessee, and West Virginia - the view is predictably different. With the cost of pollution control to run into the $20 billion to $30 billion range, says Mr. Friedman, a requirement for a 50 percent reduction would be ''a real body blow to the Midwest.'' Utility companies foresee rate increases of up to 50 percent to pay for such investments.
So the Midwesterners, parrying the Canadian thrusts of public diplomacy, have hit back with full-page newspaper ads. Their aim is to poke holes in the Canadians' ''scientific'' evidence.
They don't dispute the fact that coal-burning plants send pollutants up their stacks. And many agree that acidity in vulnerable areas - where thin soils provide little ''buffering,'' as is the case in much of Ontario, in New York's Adirondack Mountains, and in most of New England - rises dramatically after heavy rains.
But no one has yet traced sulfate ions from furnace to forest. Craig Weidensaul, head of the Laboratory for Environmental Studies at the Ohio Agricultural Research and Development Center, notes that ''the definitive link has yet to be drawn'' between the Midwest's tall stacks and the rain falling 1, 000 miles away. Nor, he says, have adequate studies been done on other possible sources of acidification closer to the impacted areas - such as automobile exhaust or oil-burning plants.
A. O. Courtney, director of Air Quality for the Commonwealth Edison Company of Chicago, agrees. There is ''no discernible trend'' toward acidity in lakes where records have been kept over reasonable periods of time, he says. He calls the linkage of acid rain to air pollution ''a simplification,'' noting that ''the interactions and transformations that occur between an emission point and the impact area are very difficult to understand.''
What is needed, he and many others say, is more research. Kathleen M. Bennett , assistant administrator of the EPA's Air Programs Office, says her agency is pursuing a 10-year, $100-million study of the problem that began in 1980.
The EPA is also going forward under the terms of a 1980 bilateral ''memorandum of intent'' with Canada that recognized the seriousness of the problem and committed both nations to reach an agreement. She also notes that funding for acid rain research has been increased 70 percent since Ronald Reagan became President.
And she disputes the Canadian claim that the US has made no special effort under the memorandum of intent to combat sulfate emissions. The 1970 Clean Air Act, she says, is already addressing the problem. She cites figures showing a 5 million ton per year drop in sulfate emissions from the 31 Eastern and Midwestern states since the mid-1970s - although she looks for a slight increase in emissions by 1985, before some aging plants are replaced at the end of the decade.
''I don't feel we need to wait until every i is dotted'' before taking further action, she notes. But she resists pressure to take immediate steps, such as those called for in a recently passed Senate bill that would require a reduction in SO2 emissions of eight million tons (from a 1980 estimated level of 22 million tons) over a 12 year period - at a cost to private enterprise, estimates Mrs. Bennett, of between $5 billion and $7 billion a year. ''We can't demonstrate that it would save a single lake,'' she says.
So far, observers on both sides agree, the Canadian approach has been effective in raising public concern south of the border. Although there are numerous bilateral friction-points between the two nations - including Canada's new National Energy Policy and its Federal Investment Regulatory Act (FIRA, the body that tightly oversees all foreign investment in Canadian business), both of which could have serious consequences for American investors - the Canadians have focused intently on acid rain.
Why such an intense pursuit of the issue?
Some Americans point out that Canadian politicians who fight acid rain are not likely to lose at the polls. If they bring the US to heel on the issue, they will be heroes - and if they fail it will be Washington's fault.
Still others note that, in a nation that otherwise seems divided over everything from energy taxes to French on the backs of cereal boxes, concern over acid rain brings all sides together.