Course Toolkit

Loon Decline in Kejimkujic National Park

1. Issue

2. Scientific Information

In United States, areas such as Idaho and Washington have only a few breeding pairs left. In other states, just one or two dozen are hanging on.

Mercury

Immune suppression (i.e. unable to fight infections and diseases) is a known side effect of mercury poisoning. Scientists have been studying Kejimkujik's mercury-laden loons to see if they are suffering from abnormal levels of infections and diseases (i.e., related to immune suppression), reduced genetic diversity, and endocrine disruption. These are all known mercury side effects. So far, the data indicates that all of these signs are present in the Keji loons.

Loons seem to be acquiring mounting levels of toxic metals, such as lead and mercury. In aquatic systems, mercury that has traveled through the air from U.S. smokestacks is taken up by bacteria in N.S. lakes. The mercury then works its way up the food chain. The mercury in the bacteria are eaten by larger organisms, and eventually by fish. The fish acquire higher and higher levels of mercury, (i.e. bio-accumulation). Mercury can be passed on by a mother loon to her chicks.

Young loon chicks are born with mercury in their muscles and bones, and are then fed fish containing more mercury.

Mercury use in industry has dropped dramatically. Coal-burning power plants are the largest single source of mercury pollution. (American power producers say it would cost US $10 billion to install scrubbers to get rid of the mercury. Meanwhile, countries like China burn mountains of coal, and the resulting mercury emissions are carried around the globe in the jet stream.)

*All fish in the eastern half of North America contain mercury; and people have been advised by health authorities that eating too many poses serious health risks. While we can choose not to eat the fish, loons and other fish-eaters have no choice.

Acid Lakes

Even slightly acid lakes can eliminate key components of the food chain for loons. Keji's lakes are very acidic, a product of years of air pollution from acid causing emissions, particularly sulphur dioxide from smokestack industries from the US. On top of that, nitrous oxide emissions (smog from cars and trucks) are increasing, which is making the acid problem worse. Before the 1970's, the park's lakes were very healthy and many loons used the lakes for breeding and nesting.

Kejimkujik's bedrock is made of granite. This type of rock cannot buffer against the acidity. (Other areas in the Maritimes, where the bedrock contains limestone, the lakes have been able to buffer somewhat against the acid rain, making them less acidic.)

Chicks need tiny fish, and invertebrates like dragonfly larvae, leeches, and other insects. In acid lakes, the key potential food items for young chicks decline and the young loons die of starvation.

Acid lakes usually kill food which fish depend upon, meaning fewer fish for both adult loons and chicks.

While adult loons can fly to more productive lakes, they cannot bring back fish for their offspring. Chicks are completely reliant on the food found in their natal lake. Acid rain will not be fixed unless we have tighter restrictions on emission controls. Joe Kereks, a retired CWS research scientist who was the first Canadian to study the problem of acid rain, recalls visiting a small Nova Scotia lake and watching a loon look for fish in the clear waters. "I knew the lake was dead. But it was there for some time before it gave up."

Cumulative Effects

Some elemental mercury is already contained in rocks when they were formed. This does not constitute a threat to ecosystems in the past. However, acid precipitation leaches this mercury from soils and rocks, which ends up in rivers and lakes.

Recreational Fishing

Entanglements in fishing line and nets are significant causes of loon deaths. (Garbage, such as beer can six-packs, plastic shopping bags are also significant killers.)

Although loons have been known to take a small fish off a fisherman's line, more often the fish has broken the line. Attracted to a fish swimming awkwardly, a hunting loon swallows the prey, hook, line and lead sinker. Death is slow but inevitable as the lead is gradually absorbed into the bird's brain and bones. Even the smallest split-shot sinker will prove fatal. Lead poisoning is probably far more significant than we know.

Scientists estimate that 500 tonnes of lead sinkers and jigs are lost in Canadian lakes and rivers every year. The vast majority of victims are never found. (As with many wild animals, loons hide when they fall ill, and we rarely see them.)

Human Disturbance Habitat Loss

Human disturbance: recreational watercrafts (particularly motorized water craft) cause significant disturbance to feeding and nesting loons. The wake of passing boats can swamp the eggs in the nests which are very close to the water edge. Some loons die each year from collisions with boats.

While Kejimkujik National Park does not allow motorized watercraft, many tourists rent or use kayaks and canoes on the extensive lake system. This recreational activity is what the Park is most noted for: a Park for canoeists.

Outside the park, there is now a new monster on many lakes, the jet ski. This personal watercraft can follow loons into the shallows where they once had sanctuary.

Cottages built around lake shores very often take up what was once loon nesting habitat. Loons are secretive birds and will try to avoid areas of human habitation. On the large Kejimkujik Lake, the Park allows visitors to camp on some islands.

By the late 1970's, the state of New Hampshire had lost half of its nesting loons because of human disturbance. For example, people fed raccoons that ate loon eggs. Gulls, drawn inland by newly opened cottage garbage dumps, feasted on loon eggs, too. Loving loons can be just as fatal as despising them: Campers, who were eager to be close to the birds, set up their tents on islands where the loons nested.

Instructor Notes

The Canadian Lakes Loon Survey believes there are between 250 000- 500 000 common loons in Canada.

It is a non-game species, so it was not economically important. In the 1970's, it was almost impossible to get funding to study them. Now they generate more money than ducks or any other bird.

The loon is a mystic symbol of the Canadian wilderness.

Many native peoples, (Cree, Inuit, and Ojibway) have tales about loons bringing sight to the blind. In one, a boy also receives the gift of being able to see things as they really are. In return, he places a shell necklace around the loon's neck. You can clearly see the necklace today.

"I'll never see 60 of them on a lake again", Jack Barr, (elder statesman, Canadian loon research community).

Fishermen viewed loons as a competitor- "the only good loon is a dead loon".

Nest close to the shore line. A drop or rise of less than one metre can mean that the nest becomes too hard to reach, or the eggs get swamped. Even the wakes of passing boats can have a negative effect.

* We now know that low levels of mercury in seafood eaten by human mothers has an effect on the cognitive abilities of their children. A 1997 Danish study showed that when pregnant women ate seafood with mercury levels well below the current World Health Organization safety limit, their children showed deficits in learning, memory, and other skills.

72 % of autopsied loons from 1993-1996, died as a direct consequence of human activities. Most were victims of lead sinkers (in Ontario 25% of deaths stem of lead sinkers), but some died from collisions with boats or cars, and entanglements with fishing line or nets. 7 were shot. Now there is a new monster on the lake, the jet ski. This personal watercraft can follow loons into the shallows where they once had sanctuary.

Scientists estimate that due to human impact biodiversity is being lost at its fastest rate ever-possibly 1000 to 10 000 times its natural rate.

There is no doubt that loss of biodiversity is gravely affecting fisheries overall.

The loon is an example of biodiversity in crisis. Human disturbance has led to the elimination of loons.

Even if emissions ceased tomorrow, decades of mercury and sulfur dioxide depositions would remain in soils and sediments.

Due to the interdependence of life, all creatures are equally important to maintain.