Scientists Recruit U.K. Anglers as River Fly Detectives

James Owen in England
for National Geographic News

July 15, 2003

London's Natural History Museum is famous for its fossilized dinosaurs
and giant replica whales, but behind the scenes, museum staff are
focusing on organisms less likely to pull the crowds. Elm trees, mosses,
and river flies are among the plants and animals causing them concern.
And in looking at ways to conserve declining populations they're
appealing to 100,000 amateur naturalists for help.

"Sharing knowledge and expertise is essential for us to maximize our efforts to conserve the U.K.'s wildlife," said Johannes Vogel, who is coordinating the Natural History Museum's Amateurs as Experts project. "We want to bring the full wealth of amateur and professional knowledge together."

Backed by various government agencies, universities, and conservation groups, Vogel and his team are particularly keen to work with anglers.

Fly fishermen are recognized for their knowledge of the aquatic insects trout feed on. In fact, it was Victorian fly fishermen, not scientists, who first studied these insects closely in order to imitate them with artificial flies. This is reflected in the English names the flies are known by. Monikers like "pale watery," "turkey brown," and "Welshman's button" were all thought up by trout fishermen.

They were also the first people to notice these flies are vanishing from U.K. rivers. Their concerns were compiled in a report published by the Environment Agency for England and Wales in 2001. It suggested a massive reduction in fly abundance. In the case of mayflies like the iron blue and large dark olive, by 66 percent and 65 percent respectively since the 1970s.

Water abstraction, agricultural runoff, climate change, and pollution from sewage treatment plants have all been blamed. But scientists say much more data is needed before they can pinpoint a cause, and this is where the fishermen come in.

River Fly Workshops

The Natural History Museum is now staging workshops around the country where anglers are taught to monitor river fly populations using scientific methods. Their findings can then be presented to government scientists for further investigation, or passed to national recording schemes for the three main groups of river insects: caddisflies, mayflies, and stoneflies.

"At the moment very few people contribute to our records," said Steve Brooks, a research entomologist at the museum. "We want fishermen to help us to build up a better picture of the distribution of these insects."

Brooks says the trouble with the current data is that it's hard to tell whether a species is disappearing from a river because it's unlikely there's any scientific record of it being there in the first place.

"It's in fishermen's interests to get involved because there really isn't anyone else to do it for them," Brooks said.

Conservation efforts tend to focus on those high-profile, easy-to-recognize species that grab the public's attention. If dolphins, eagles, or otters have a problem, people usually listen. But when it comes to drab, barely distinguishable bugs that spend most of their lives as underwater larvae, Brooks says it's only trout fishermen and entomologists who miss them.

Even when compared to other insects, river flies are overlooked. National conservation plans are now in place for 11 British butterfly species. Caddisflies and mayflies are yet to get one.

Caddisfly expert Peter Barnard, one of the river fly workshop tutors, highlights the plight of a species anglers call the grannom. It once hatched out in huge numbers on England's best known trout river, the Test in Hampshire, providing spectacular sport for anglers.

Caddisflies In Decline

"Fishing records from the 19th century show the grannom was once the most abundant fly on the Test in spring, but today we hardly see it at all," Barnard said. "Nobody knows why they've disappeared."

Barnard hopes regular monitoring of caddisfly numbers by anglers will help solve such mysteries. And the signs are they're keen to assist the professionals.

"I've always been driven by a love of nature and a need to understand my local environment," said Anthony Bridgett, a member of the Leek and District Fly Fishing Association in northern England. "Over the last 30 years I've seen a definite decline in river insects. As fly fishers spend so much time in the water, I think we're in the ideal position to investigate this trend."

Already this year six workshops have been held in England and Scotland. Free of charge, they're open to anyone interested in monitoring aquatic insects.

The Natural History Museum is also recruiting amateur naturalists to gather data on a range of other threatened wildlife.

This fall, for example, the museum is teaming up with walkers throughout Britain to map the country's last surviving mature elm trees. A disease spread by wood-boring beetles has wiped out 20 million elms since the 1970s. The trees are particularly important to conservationists as they support a unique community of species including a rare butterfly, the white-letter hairstreak (Satyrium w-album).

Bridget Peacock, an entomologist working on the museum's Amateurs as Experts project, said: "It's about bringing people together with a common interest who perhaps haven't had the opportunity to collaborate before."

The message is clear: conservation is for everyone, not just the experts.