Saving Salmon: Rescuing Coho Fry in Cowichan
A look into the annual Coho fry rescue on Cowichan Lake.
This is the first installment in a three-part series about saving salmon on Vancouver Island. Read the second installment here.
By: Katia Bannister
On a warm and cloudy morning in early July, I joined Parker Jefferson, Dave De Pape, and Rob Williamson in the parking lot of the Lake Cowichan Tim Hortons to prepare and strategize for a day of “fry rescuing” in and around Cowichan Lake, specifically in the Robertson River and Meade Creek. This trio of fry-rescuers had begun many of their days in the watershed by meeting here. Sometimes alone, and sometimes joined by other keen volunteers with an interest in river stewardship and the health of local salmon — such as myself.
The annual fry rescue in Cowichan Lake is coordinated by the Cowichan Lake and River Stewardship Society and the Cowichan Lake Salmonid Enhancement Society and takes place in the tributaries — small streams or rivers — that feed into Cowichan Lake. The two organizations have a long-standing agreement with the Canadian Department of Fisheries and a permit to undertake a yearly rescue of Coho fry.
To anyone familiar with the life cycle of Coho salmon, that last sentence might read a little odd. Coho salmon typically spend the first halves of their lives feeding and growing in the freshwater streams where they hatched from their eggs and where their parents spawned, until they are ready to migrate to the ocean where they spend the rest of their lives foraging in estuarine and marine waters of the Paciﬁc Ocean. So why are the Coho fry of Cowichan Lake rescued from the tributaries they are supposed to be growing or rearing in each year?
Well, if they weren’t, it would mean certain death for these fry. As the hot summers of the Cowichan Valley take hold, a rapidly falling water table and increasingly drought-like conditions quickly begin to dry up the tributaries or streams that feed into the lake, and where the salmon spawn; turning once safe havens and prime rearing grounds into ever-dwindling prisons. Due to these annually consistent drought conditions, rearing in the tributaries of Cowichan Lake is not a viable option for the Coho fry, and they know this. Just as salmon have both amazed and mystified scientists for decades by knowing how to swim all the way from the ocean, back to the exact same places they hatched to then lay their own eggs.
But as the salmon-bearing tributaries of Cowichan Lake begin to dry up in the heat of the summer sun, a mass exodus takes place. The fry, sensing the water levels dropping around them, start to head enmass downstream towards the confluence — the place where a tributary meets the waterbody it flows into. Many fry will make it out in time, just before a combination of drought conditions and evaporation bring the water table just low enough to turn the tributaries of Cowichan Lake into rapidly shrinking pools of water. Once past the confluence, the salmon will continue to feed and rear only now in the lake itself. “It’s unusual — it’s like a Sockeye life cycle these Coho have,” said Parker, “but they've evolved to rear in the nearshore areas of the lake.”
That is, those who make it downstream before the tributaries begin to pool. Many more fry don’t make it out of their tributaries in time, and find themselves landlocked; unable to reach the lake. They are left to swim aimlessly in the tributaries as they dwindle down to mere pools. And as temperatures rise in the Warmland, the fry are left without refuge as the water around them retreats further, and begins to simmer in the summer sun. Interestingly enough, these pools will at least initially create the perfect habitat for the growing Coho fry. “The ones we pull from the pools are really big and healthy because the habitat’s perfect,” exclaimed Parker. “There’s lots of food, and the temperature’s ideal, but it’s going to come to an end when the thing dries up.” Or perhaps even before then as big healthy Coho fry can look like a tasty snack to predators, and stuck in their shrinking pools, there is hardly anywhere for the fry to hide, and nowhere for them to swim.
But that’s where the work that Rob, Dave and Parker do comes in. And despite what some might assume because of current drought and weather conditions, there were fewer salmon to save this year than others.
“It’s actually been a good year for us,” Parker shared with me as we readied ourselves for the fry rescue. “That might change soon though with the heatwave” Dave quickly added. Parker nodded, finishing by saying, “The critical time for fry is in the Spring. The fish hatch — and it depends on the water temperature — anywhere between March, April, May, June, and then the fry come out of the gravel.”
This year, the rains of the spring and early summer flushed many of the Coho fry from the tributaries before they dried up, but Parker cautioned me that this was not always the case. “In a drought year sometimes we have to start the fish rescue in May, April or even March!” He exclaimed. “And in those summers we’ll move over a hundred thousand fish. But the last couple of years, where we’ve had a nice wet spring and early summer and most of the fish migrate out by themselves, we will attend those same pools — because the pools mostly stay in the same place every year — and get maybe twenty-five thousand fry. So it’s a big difference.”
With all the talk out of the way, we packed up and hopped in the car to drive to Meade Creek — the first tributary we were inspecting for stranded Coho fry — to see just how big a difference it was.
At Meade Creek Parker, Dave, and Rob suited up in water-ready shoes, rolled up their sleeves and pant legs, and grabbed their pole seines — handheld devices made from mesh netting strung between two wooden dowels that are used for capturing fry.
Rob, Dave and Parker on the “seine” - Photo by Katia Bannister
The trio of salmon rescuers then waded into the first of the small pools that lined the mostly dry riverbed and began combing the water with their seines. Using the pole seines for fish rescuing success takes a great deal of strategizing. Salmon fry — not knowing that Dave, Rob and Parker are there to help — can easily evade the nets, escaping underneath them and to the side. So a variety of catchment strategies, including walking side-by-side to cover the breadth of the pool, and “pinching” — where two seiners walk towards each other, and once their seines meet, they lift them up, catching the fish that tried to flee in the opposite direction.
Salmon fry getting placed into their temporary transports - Photo by Katia Bannister
Post-capture, the salmon fry were deposited into orange and white Home Depot branded buckets filled with the cool river water that remained in the pools. Because so many fish occupied each bucket, rapidly deoxygenating the water as they respired, it was essential that a “bubbler” — a kind of air pump — was added to each bucket to aerate the water, making it a safe temporary environment for the fry to be transported in. And once all the pools at Meade Creek were seined for fry, and all the buckets were chock full of fry, we loaded up our rescuees and supplies into the truck, and Rob climbed in the back to keep a closer eye on the bucket of fish and prevent sloshing and tippage as we drove along the bumpy roads.
Rob sitting-pretty with his buckets of fry - Photo by Katia Bannister
When the vehicles stopped again, each bucket was carefully unloaded and carried down to a small community dock at the edge of Cowichan Lake. Slowly, and with a high degree of care and precision, Dave, Parker and Rob, measured the temperature of the water in the lake and the buckets, adding lake water to the buckets until they reached the same temperature as the lake, about 7 degrees difference. Parker explained to me that this is so the fry did not experience a temperature shock — which can result in consequent death — once released into the lake, which would of course diminish the point of our fish rescue. While waiting for the temperatures to match, Parker also told me more about our catch. He confirmed that most of our rescuees were indeed Coho fry, but not all of them.
“The other fish we're getting are Cutthroat Trout, and they’re the predators,” explained Parker. “Cutthroat are the biggest fish in the lake, and the reason is because they eat all the small fishes. The Cutthroat spawn in the same places as the salmon, and they hatch, and they look around, and then instantly get bigger than the Coho fry. So they start to eat them and then they get even bigger.” He chuckled a bit before saying, “Sometimes when we release the fry a big cutthroat will come out from under the dock and just start eating them!”
Cutthroat trout and Coho salmon side-by-side - Photo by Katia Bannister
Luckily though, as Rob gently lowered, and then tipped each bucket of fry into the lake, no big trout emerged from beneath the dock to gobble the young salmonids. And we watched the young salmon take to freedom and dart quickly into the green weeds in the shallows of the lake. A successful fry rescue.
Rob releasing Coho fry into Cowichan Lake - Photo by Katia Bannister
Walking back up to the vehicles, Dave, Rob and Parker expressed to me how keen they were to train other community members, particularly young people, to be the next generation of “fry rescuers” in Cowichan Lake. “We’re really glad to see you came out,” said Parker. “We want to recruit people to come out and learn this stuff. Because us old guys come out, but when you've got a five-gallon pail with a few hundred fry in it, and you’ve got to walk a kilometre down a dry river bed, and you’re seventy years old…” He trailed off with a chuckle. “The point is, we want more young people coming out.”
So while they’re still keen to put on waders, and participate in the fry rescue for years to come, Parker, Rob and Dave are ready to start the process of passing the pole seine and allowing youth to build the skills, values, and passion that will carry the Cowichan Lake fry rescue forward for years to come.
Are you keen to get out in the Cowichan watershed? To learn more about the annual fry rescue in Cowichan Lake, and join in other hands-on initiatives to protect salmon in the Cowichan watershed, contact [email protected], or check out CodeBlue BC — a campaign to secure and sustain BC's fresh water sources. CodeBlue BC is currently recruiting for their Cowichan Valley Community Team. Join them, or start a team in your community by emailing [email protected].