If you wanted to bring an ecosystem back to life, probably the last place you'd start would be in the dark, beneath the docks at Squamish Terminals.
But there, in the cool, dripping intertidal zone under the deep water terminal, 45 kilometres north of Vancouver, a small group of volunteers has solved an environmental mystery – and restored a herring run long thought lost.
The Miracle of Howe Sound, as it might be called for helping to revive an entire ecosystem, began one cold, spring morning in 2006, when members of the Squamish Streamkeepers went looking for signs of herring spawn in Mamquam Blind Channel. The inlet, near the port at Squamish Terminals, was the focus of a federal government effort to restore fish habitat damaged by industrial pollution.
Eelgrass beds had started to sprout because of cleaner water in the channel, but there was no sign that herring had made a comeback after vanishing from the area decades earlier.
Then some watchmen at Squamish Terminals told the Streamkeepers they thought they'd seen a milky cloud of herring spawn near the wharves.
"One of the guys walked under the dock and said, 'What's all this yellow muck on the creosote pilings?'" said John Matsen, herring recovery co-ordinator for the Streamkeepers. "I said, "I dunno, some kind of a mould maybe? Who knows?' Then we started thinking these kind of look like eggs ... it turned out those were hundreds of millions of dead herring eggs on these creosote pilings. So we thought, okay, now what do we do?"
Standing in the mud, their flashlights playing over the pilings exposed at low tide, the volunteers could see layer upon layer of herring eggs that had been deposited on creosote-treated wood.
Creosote is a coal tar product that is widely used to stop wood from rotting. The black, sticky substance, which can be found under just about every timber dock in Canada, contains polycyclic aromatic hydrocarbons. For more than a century, creosote has played a vital role in protecting wood, and it has long been regarded as environmentally acceptable because only small amounts of chemicals leach out into the water.
But a U.S. study in 2000 found that when herring eggs are directly exposed to creosote, the mortality rate is 90 per cent. The chemicals penetrate the fish embryos, halting development of the eggs after only a few days.
At Squamish Terminals, where the overhead wharf provides shelter from predators and spring frost, the herring had chosen to spawn on hundreds of pilings that were death traps for their eggs.
Mr. Matsen said herring apparently came back in to Squamish waters in 1999, when a log boom from up the coast was towed into port, with some freshly laid eggs adhering to bark. The offspring from the log boom eggs later spawned under the Squamish Terminal – but they were in effect "committing suicide" on the creosote-treated pilings, Mr. Matsen said.
Looking for a way to protect the eggs, Squamish Streamkeepers went under the docks the next spring and began wrapping creosote pilings with different kinds of plastic, hoping to find a covering that both appealed to the herring and blocked chemicals from reaching the eggs.
"Lo and behold the herring came in and spawned," Mr. Matsen said. "We went under the dock [in]early March and we saw eggs covering all these materials."
The eggs on uncovered creosote had all died, but where the pilings were wrapped, the eggs were thriving.
The Squamish Streamkeepers have since wrapped 170 pilings (a plastic material used for weed control seems best), and they hope to wrap another 400 pilings when they have funding to buy more materials and hire a diver to work below the low tide line.
Mr. Matsen said they have advised other community groups, and now pilings are being wrapped in several locations on the coast. Vancouver's False Creek, however, has not been treated yet because it is just too big a task.
"There are too many pilings – there are thousands and thousands of pilings in False Creek," Mr. Matsen said.
The big schools of herring returning to Squamish Terminals have not gone unnoticed – and are credited with drawing grey whales, killer whales and dolphins back to Howe Sound.
Mr. Matsen said this spring's herring run seems like it might be the best ever.
"They are coming back now and it looks strong," he said, with the main run expected in mid-March. "Just judging by what we've got so far, my best guess would be 600 tonnes are coming back. Hopefully this is a run that will set an example for fisheries management in other areas on the coast."
Mr. Matsen said the revival of Howe Sound probably wouldn't have been possible without a federal-provincial project that a few years ago cleaned up nearby Britannia Creek, which once had the worst acid mine pollution in North America.
But it was the discovery under the wharf that sparked the herring rebound.
Mr. Matsen said one of his concerns is that the return of herring could lead to the return of the commercial herring fishing fleet, which scoops up hundreds of tonnes of fish each spring, just before they spawn.
"You've got to leave them alone and let us bring back the numbers," he said.
Lisa Mijacika, pelagics co-ordinator for Fisheries and Oceans Canada, said there is no herring fishery in Howe Sound this year, and none is planned.
The herring population in Georgia Strait is healthy, she said, and the "stock biomass" is estimated at 138,000 tonnes. The commercial fleet will harvest about 18,000 tonnes, but Ms. Mijacika said the catch "isn't taking place anywhere near" Squamish Terminals and shouldn't impact that population.
David Ellis, a conservationist and former fisheries planner with a long interest in herring, said the Squamish Streamkeepers have done a remarkable job of restoring a local herring population and he hopes the idea spreads.
"It shows you how a community can get together and make a big difference with a little bit of money and a lot of hard work," Mr. Ellis said. "It's a great template for the whole coast."
Creosote fallout in the U.S.
Creosote-treated wood is widely employed in Canada, but in the U.S. some jurisdictions are restricting its use, or are systematically removing old pilings because of environmental concerns.
Since 2000, Washington State Ferries has been working to replace all creosote timbers in its docking facilities. By later this year it expects to have replaced 15-million board feet of creosote timbers in Puget Sound.
The Washington State Department of Natural Resources has collected and removed from beaches more than 5,000 tonnes of creosote-treated logs since 2003. And since 2004, the Port of Port Angeles has prohibited the installation of creosote-treated timbers.
The California Coastal Commission recommends that creosote-treated pilings be wrapped in plastic to prevent leaching of chemicals into water.
In 2004, the New York State legislature voted to phase out the manufacture, sale and use of creosote, but the bill was vetoed by the governor.
The Rhode Island Coast Resources Management Program states that no residential docks, piers or floats should contain creosote-treated timbers.
A 2006 report for the National Oceanic and Atmospheric Administration states: "Effects observed in exposed [fish]embryos included decreased hatching success, DNA damage, reduced heart rates, and gross morphological abnormalities such as scoliosis, pericardial edema, and cranio-facial abnormalities."
- Mark Hume