Sunscreen a suspect in river’s decline
COWICHAN LAKE — On soft, early summer mornings, Joe Saysell would get himself a cup of tea, settle back in his deck chair outside the small house he built for his wife, Gail, and enjoy nature’s free light show.
Shafts of sunlight, lancing through the numinous green beneath old growth cedars, Douglas fir and broad leaf maples arching over the Cowichan River, would glimmer on the wings of countless mayflies, stoneflies and caddis flies.
Each consecutive hatch of insects would struggle through the surface film on B.C.’s blue-ribbon heritage stream, flutter skyward, then drift upstream in gossamer clouds carried on the river of air that always runs counter to the current sweeping down through Willow Run about 50 kilometres upstream from the Island’s east coast.
“Whenever there’s a hatch, it’s magic,” muses Saysell, a long-retired logger and fishing guide. “It’s like shimmering snow flurries. You watch the flies whirling above the river and up into the tree branches looking for mates.”
But these mornings, he doesn’t watch. There’s no point. The insects have all but vanished. Hatches that once began in midApril and continued into July, he says, are now finished in a scant two weeks.
And science from as far away as Hawaii, Australia and the Caribbean, from the snow-fed streams of the Alps to the sewers of Barcelona, hints at commonly used sunscreens as a leading suspect in the insects’ disappearance.
There are other factors, of course. New property-holders who strip the willows that provide critical insect habitat from the banks to mistakenly improve cosmetics — mistakenly because soon they’re frantically replanting to prevent erosion of their river frontage. Logging that’s altered the seasonal flows of the river. Industrial water extraction for a pulp mill and use of the river to dilute municipal sewer effluents. Climate change.
The chief concern for Saysell, though, is the slick left on the water by swimmers who are widely advised to slather on sunscreen to protect themselves from harmful solar radiation. The precautionary advice is understandable. The U.S. National Cancer Institute reports that cases of melanoma, the deadliest from of skin cancer, have tripled since 1970, and the melanoma death rate for white men, the highest risk group, has more than doubled.
Might declines in aquatic insect populations that Saysell says he’s witnessing be an unintended environmental consequence of an important public-health effort to prevent skin cancer?
“Right now, we should be seeing a stream of caddis flies moving up the river. Mayflies. Clouds of midges,” Saysell says. “I went walking up and down the river this morning. I couldn’t find any caddis flies. Not one. There should be lots of them. It’s been like that for the last two or three years.”
Saysell, who has spent more than 60 years on the Cowichan and knows it as well as he knows his own skin, worries that the hatches of winged insects are vanishing because of sunscreen residues left by tourists who drift the river’s beautiful upper reaches during the summer on inflated inner tubes and air mattresses.
“Any hot weekend day I can see 1,000 to 1,200 tubers drifting past,” he says. “We call it the Tuber Hatch.”
In the U.S., researchers discovered that 1,200 swimmers would go through 76.8 kilograms of sunscreen a day and that the mist from aerosol sunscreen carries for 450 metres.
“When there are tourists in the water causing sunscreen pollution, a lot of it will be on the surface causing a sheen — where most of the insect adults will be exposed to high concentrations,” says U.S.-based Craig Downs, lead scientist on an influential 2015 paper published in the Archives of Environmental Contamination and Toxicology that outlined the alarming new risk for marine organisms.
“Trout fry will be especially exposed because of their feeding habits near the surface of the water, while in their embryonic forms they will be exposed from the source of sediment that is dependent on past contamination from sunscreen pollution.”
On the Cowichan River, there’s much potential for just such contamination. Tubing has emerged as such a popular pastime that entrepreneurs now rent inner tubes at the outlet on Cowichan Lake and retrieve them hours later when the drifters pull out at a small sandy beach kilometres downstream.
River is renowned
Fourteen years ago, the Cowichan was designated as both a national and a provincial heritage river in honour of its long history as B.C.’s most famous trout-fishing stream. For millennia, its salmon runs served as a feast bowl for the Cowichan Tribes.
It’s been renowned among sports anglers for more than a hundred years. Early in the last century, fly-fishing clubs in New York and London posted the daily action on their bulletin boards, catches were reported in the New York Times and it was a favourite of the Prince of Wales.
Paul Smith, who wrote nostalgically about the river for the Victoria Daily Colonist’s Sunday Magazine almost 70 years ago, began fishing the upper Cowichan in 1898 when a fly-fishing trip meant travelling by horse from Cowichan Bay.
“There were few fishermen and these mostly, as I remember, globe-trotting Englishmen of the old aristocracy. They had come from the ends of the Earth to fish in the Cowichan,” he wrote. These “frostyeyed” artists, he said, shamed him out of angling with worms. And it was the insect hatches in June and July that provided these connoisseurs of the dry fly with “the best fishing that was to be had.”
Those elite anglers made pilgrimage by steamship, train and stagecoach. Now they come by jet plane. Their angling on the Cowichan has served as a century-long mainstay in a provincial sports-fishing sector that today contributes more than $250 million to B.C.’s annual gross domestic product.
Today, the secluded pools, swimming holes and rapids — all flanked by a 20-kilometre trail — are no longer the exclusive preserve of angling gentry with split cane Hardy rods and delicate dry flies. Protected by its heritage status and a 1,414-hectare strip park, the Cowichan has evolved into a shared-use mecca for hikers, whitewater kayakers, campers, picnickers, swimmers and tubers. And most of them use sunscreen.
Saysell doesn’t blame the tourists for the plight of the insects. Nor does he object to the tubers’ desire to stay safe while they share the beauty of the river as it eddies through the forest.
He does worry about whether such a simple thing as the sunscreen that swimmers and tubers use — a large provincial government sign urges them to do so at the launch point — translates into an ecological hazard when it inevitably washes off in the river.
Nanoparticles in the food chain
Consider the aquatic life cycles of those caddis flies that Saysell couldn’t find. In their larval stage, caddis flies encase themselves in tiny suits of armour for protection as they crawl around the undersides of river stones. As pupae, they rise into the water column and wait to transform into winged adults that fly upstream in search of mates to renew their life cycle.
And like all the other insects that spend most of their lives in the water, they provide a crucial part of the food chain for the river’s prized game fish. Aquatic larvae provide up to 80 per cent of the diets of resident rainbow, brown and cutthroat trout and the transient juveniles of steelhead, chinook, coho and chum salmon. Their importance is evident from the many fly patterns devised by anglers seeking to mimic them in all their forms.
Scientific research increasingly suggests that Saysell’s worries have genuine merit.