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Acid Rain

Poison Rain
In half a tragic lifetime, Nova Scotia has sacrificed 23 Bay of Fundy rivers to stock collapse and 34 Atlantic coast rivers to acid rain, with a further 16 rivers acid-damaged. In other words, within 30 short years, the vast majority of Nova Scotia salmon runs have been destroyed. Only a handful of short, fall-run streams remain healthy in a Canadian province that was not long ago celebrated as a three-season salmon destination.

Equally tragic is the sobering reality that the government department legally responsible for the management and protection of migratory fish in Canada (DFO) seems content to simply sit back and watch it happen.

Acid rain is formed when fossil fuels are burned, sending sulpher oxides (SOx) and nitrogen oxides (NOx) into the atmosphere. A chemical reaction takes place in the atmosphere resulting in these compounds becoming sulphuric acid (H2SO4)and nitric acid (HNO3) which fall as rain or snow.

The major soucre of acid rain causing emissions are the U.S. Midwest and Central Canada.

Nova Scotia is unfortunate in that it lies in the path of the prevailing winds from these areas. Nova Scotia's poor buffering soils in the southwest section of the province prevent it from effectively buffering or neutralizing the effects of acid rain.

Decreased pH levels resulting from acid rain have many negative affects on salmonids. The acid leaches metals from the soil, some of which accumulate in the fish, particularly the gills resulting in physiological stress. The end result is poor reproductive ability. If eggs are successfully layed, the acid results in either death of the eggs or to the emerging fry.
Anyway you look at it, acid rain has been devastating to salmon populations in Nova Scotia.


An Unprecedented Loss
THE UNENVIABLE DISTINCTION of being the most heavily impacted area of North America in terms of percentage of fish habitat lost due to acid rain is held by Nova Scotia.

Atlantic salmon are particularly sensitive to acidity, more so than Brown or Brook trout, and fully one third of salmon productivity has been lost in a province that only half a lifetime ago prided itself on rivers teeming with this priceless natural resource.

The enormity of the problem is identified by drawing a line all the way from Digby, on the western tip, to Canso, on the Eastern tip of the mainland of Nova Scotia. With few exceptions, the area south of this line, almost half the entire mainland, is ultra-sensitive to the effects of acid precipitation. (See map.)

Bear in mind that in general terms, Atlantic salmon often have difficulty reproducing in water of pH 5.5 - and that pH 5.0 on the logarithmic pH scale is toxic to them. Currently, 14 rivers in Nova Scotia have a mean annual pH of less than 4.7 and their salmon runs are extinct. These include once celebrated salmon streams like the Jordan, Clyde, and Sable to name but a few. A further 20 rivers have a mean annual pH of 4.7 to 5.0 and have only remnant populations in one or two tributaries. Rivers such as Bear, Nictaux, Mersey, East River Sheet Harbour and Tusket (the latter four having been further damaged by hydro dams) are included in this list. And finally, a further 16 rivers have mean annual pH values of 5.1 to 5.4 and have salmon stocks depleted in some tributaries, but in the main stem and less affected tributaries production appears normal. Rivers in this category include such well-known streams as the Gold, LaHave and Medway on the South Shore; and Moser, St. Marys and Liscombe on the Eastern Shore.

The impact on the province of the loss of these rivers has been severe. Salmon angling licence sales have declined dramatically with resulting loss of outfitting operations and reduction in the number of guides as people seek other sources of income. Granted, all of this cannot be solely attributed to acid rain: the mysterious decline of salmon globally (including the collapse of salmon runs in an additional 23 Nova Scotia rivers draining into the Bay of Fundy) has provided a double dose of tragic news for Canada's "Ocean playground" whose Department of Tourism no longer bothers to promote angling.

Since 1989, salmon angling licence sales in the province have plummeted by 70 per cent. It goes without saying that the area with the lowest resident salmon licence sales is the area most impacted by acid deposition.

Several rivers have maintained artificial angling opportunities during this period. The Clyde River, for example, has had a put-and-take salmon fishery in the estuary for several years where hatchery-raised smolt are released in the lower section of the river and returning adults are targeted in the estuary upon their return. The river is so acidic as to be toxic to salmonids, thus getting the fish to the headwaters would be pointless. It is especially depressing to see those river-lake systems in the area made famous by the timeless book "The Tent Dwellers", a historic tribute to Nova Scotia's once prolific salmonid resources, now completely unable to sustain salmon, while only tiny remnant populations of trout still exist in pockets of higher pH water.

For years, as the effects of acid rain were being monitored and understood, the federal government was able to maintain river specific stock genetics through the hatchery system. In fact, some of the early work on mitigation techniques was conducted at these facilities. Hope existed that these river specific stocks could be maintained until acid depositions decreased as a result of the Clean Air Act.

But in 1997, the hatcheries were divested by the government into private hands as a cost-cutting measure and the federal Department of Fisheries & Oceans appeared to walk away from its constitutional mandate to conserve fish stocks. This was especially frustrating given that the British Columbia hatcheries appeared not to have been touched. The same government department that finds funds for hatcheries to support a massive commercial fishery on one coast has "divested" its ability to preserve distinct stocks of a species that in some areas is heading for the endangered list. For reasons that remain obscure, an offer by the Nova Scotia Government to assume responsibility for federal hatcheries was declined.

While DFO assured that nothing would change and the hatcheries were divested with the agreement that stocking would be maintained for the public good, most of those involved in fisheries conservation in Nova Scotia harbor reservations that, notwithstanding the fine efforts of those now involved in the privatized hatcheries, sufficient funds can be raised outside government to operate these facilities. The loss of accumulated years of in-house expertise leaves very serious questions about the long term outlook and Nova Scotia's ability to "hold on" until acid conditions eventually improve. The agreements under which the private groups run these hatcheries are for five years. What happens after that is unclear, and certainly no-one expects the pH problem to self-mitigate in that time frame.

During the decline in pH and fish stocks, governments were involved in monitoring the scope of the problem and working on ways to mitigate for acid rain. But budget cuts resulted in this section of DFO being shut down and programs devoted to solving, or even monitoring, the problem simply abandoned. With the signing of the Canada/United States Clean Air Agreement in 1990 came a prevailing public perception the acid rain problem was resolved; and in fact the very effective Acid Rain Coalition was disbanded. The reality, however, is that the problem is far from resolved and we have little current knowledge of its extent.

In the absence of government involvement, several conservation groups in Nova Scotia have taken to liming headwater lakes. This is expensive, labour intensive, and potentially dangerous, as volunteers drive all-terrain vehicles towing lime spreaders across (hopefully) frozen lakes. The available weather window for this activity can be quite small as the thickness of the ice is a determining factor. The winter of 1998/1999 was so mild that ice was not sufficiently strong to allow any lime to be spread. To effect the desired impact, lime must be spread each winter for a period of five to 10 years or until residual buildup of neutralizing capacity is achieved in the lake. The effect of missing last winter is unknown.

Widespread frustration with government's perceived lack of concern has turned to outright anger as the pH problem now becomes a convenient rationale for pulling back in other areas. For instance, low stock numbers and low pH are being used as an excuse to allow a hydro dam to be rebuilt on the East River Sheet Harbour, in this day and age, without a fishway. The worry now is that this excuse will be used elsewhere, to the detriment of already terribly low numbers of salmon.

There is no shortage of resolve that we must find the way to neutralize the impact of acid rain, claw back the habitat we have lost, and continue to demand that the responsible authorities do everything possible to reduce emissions at source.