BURNABY NOW (British Columbia) 10 November 10 Tracking the turtles - Stalled dredging cost millions but has reaped scientific side benefits (Jennifer Moreau)
On a bridge over Deer Lake Brook, biologist Karen Truman unfolds her antenna and attaches it to a small, box-like radio receiver. Truman works for ENKON Environmental, the consultants hired to keep an eye on Burnaby Lake's fish and the endangered Western painted turtles while the city completes a massive dredging project.
Truman pulls out a small piece of paper with codes written in pencil. Each one responds to a turtle they've caught and tagged for tracking purposes. Each tagged turtle gets its own radio frequency, so all Truman has to do is tune in to the right channel to find the turtle she's looking for. With the antenna pointed south over the brook, the receiver box starts bleeping like a weak, electronic heartbeat.
"See," she says excitedly, honing in on "M24" - an adult male turtle somewhere in the tributary. "Isn't that wild? He's not very far. Whoa, he's close."
We can't actually see M24, he's underwater, but the bleeping receiver assures us he's there.
The species Truman is tracking was at the centre of a controversy last year, which put the brakes on the city's multimillion-dollar dredging project for about five months. The provincial Environment Ministry held up one remaining permit over concerns that the red-listed species was in harm's way while the dredging was set to start. The holdup cost the city millions of dollars, while the contractor's equipment sat idle by the lake, and a squabble broke out between then-environment minister Barry Penner and Mayor Derek Corrigan.
The city brought in ground-penetrating radar from Italy, which had to be specially adjusted for use on water, to make sure there were no turtles hiding in the mud before the dredging began. So far, none has been found with the radar, but 32 have been tagged in the past five months. And for the first time in the Pacific region, biologists like Truman are intimately tracking this endangered species and collecting data that may help protection efforts.
"This study is very important, and nothing's been done like this before," Truman said.
According to a 2006 report from the Committee on the Status of Endangered Wildlife in Canada, there are fewer than 500 known Western painted turtles in Canada, and only 129 in B.C. Burnaby Lake holds one of the biggest known populations in the region with at least 50 turtles, possibly up to 100, although no one knows for sure because ENKON is still collecting data.
On the coast, the main threat to the turtles is road construction and the loss, degradation and fragmentation of wetland habitat. Their numbers appear to be declining, according to COSEWIC.
The turtles have been known to bury themselves in the mud during winter, and the fear was that dredging Burnaby Lake would literally chop them to bits. Apparently, the turtles were active throughout winter, even when the lake was covered with ice, says Lambert Chu, the city's engineering director.
"Definitely for those people who believe the painted turtle hibernates by burying itself in the mud, that's not the correct conclusion based on observations," Chu said.
What they have observed is that the turtles move into the tributaries where the water is shallower and there's more vegetation at the end of August or in early September. They also like the area where the lake drains into the Brunette River. They don't use the middle waters much, unless it's summer and they need a "transportation corridor" - as Chu puts it - to get from one side of the lake to the other. They even have a favourite log in Deer Lake Brook to sunbathe on when the weather is nice.
If there are any turtles found in the active dredge zones, ENKON has to move them to a tank in the project's treatment facility by the shore. Truman says there was only one found in an inactive zone, but it moved before dredging started.
"They've been proven to swim across (an inactive) dredge zone, climb over a silt curtain and be on their way," she says.
Biologist and turtle expert Vanessa Kilburn first raised concerns about the dredging project potentially harming the endangered turtles. She says it's important to know that before this study was done, nobody knew much about the movement and overwintering habitat use of the turtles on the Coast.
"All of our information on the species comes from interior Canadian and American populations that overwinter in very cold conditions, with thick ice that forms and stays all winter long.
"In those locations the turtles do bury into the mud to hibernate, and there is tons of scientific literature on that. Because no information was available on the species' hibernation needs on the coast, scientists - like (those) at the Ministry of Environment - had to make a judgment call since the species is red-listed, and that judgment call was made based on the only available information we had," she says.
"It is lucky for the city - and the turtles - that they do not appear to do the same thing on the coast, or at least not in Burnaby Lake. But before this study was done, nobody knew what they did, and so we had to take precautions to ensure that the turtles were not killed."
While the city's position has been that they did what the Environment Ministry asked of them, Kilburn says Burnaby was told in early summer to do a radio-telemetry study to track the turtles before dredging started.
"If they had listened in the first place, none of the holdup and loss of money would have occurred," she says.
Meanwhile, two dredge machines work in tandem, 16 hours a day, pulling up sludge from the bottom of the lake. Chu expects the project to be finished in March 2011.
Thanks to sediment filling up the lake over time, the water is too shallow for boats, and the deepest area is about 2.5 metres.
Dredging will restore a rowing channel and create a better environment for wildlife, Chu says. Once the water is deeper and cooler, there will be more oxygen for fish to breathe.
"If you become a marshy area, another Burns Bog, you basically displace aquatic animals," he adds.
Meanwhile, Truman and her colleagues keep patrolling the lake for turtles, tuning into their channels and listening for electronic pulses. And sometimes, when the water's clear, they can see a turtle.
For the best location to spot the Western painted turtle, see Jennifer Moreau's blog, Community Conversations, at www.burnabynow.com. Click on the Opinion tab and follow the link under Blogs.
Stalled dredging cost millions but has reaped scientific side benefits