“From the [Sproat River] bridge to the lake, there was minimum mortality, perhaps 300 fish. Around the fishway, it started to pick up, and below the fishway I counted four or five thousand.” ~ Hupacasath fisheries biologist Graham Murrell.
A major die-off of sockeye salmon in the Somass River system does not spell disaster, but it serves as a warning about the effects of prolonged drought, according to fisheries biologists from Tseshaht and Hupacasath First Nations.
When Nitanis Desjarlais saw the first few sockeye coming into the side channel of the Somass River that flows in front of her home last week, she thought it was a good sign. But then they all began to die.
Desjarlais and her partner John Rampanen live in a rental property at the end of Hector Road, and usually spend plenty of time at the riverside with their children. But late last week, with temperatures climbing and the air thick with smoke from the Dog Mountain wildfire, those unexpected visitors began to roll over and accumulate on the shoreline.
“On the first day, there were just a few, and I thought, ‘Oh well – Circle of Life,’ and I set them out for the eagles,” Desjarlais said. “But when I came back later, there were dead fish all over the place.”
The morts included juvenile salmon and small, native freshwater species like sticklebacks. When Desjarlais first realized the enormity of the die-off, she put out the alarm and posted graphic photos on her Facebook site.
When Ha-Shilth-Sa visited Desjarlais’ home on July 14, most of the dead fish were in an advanced stage of decomposition, although there were a few afflicted fish still showing signs of life. But there were also dozens of clean, fresh-looking sockeye milling around in the pools and nosing up to the tiny, cool stream that trickles through the property and into the river.
“John and I spent a lot of time cleaning up the brush and improving the channel,” she explained.
The good news is, the abrupt weather change on July 10 brought immediate relief. With cooler temperatures and rain, the timing was just right for a planned release of water from both Sproat Lake and Great Central Lake. Those twin pulses of lake water simultaneously raised levels in the river and lowered the temperature. That, in turn, brought a huge surge of fresh sockeye into the river system and through the counters at Sproat Lake and at Stamp Falls.
“We’ve had up to 15,000 fish in one day at Sproat Lake,” Hupacasath fisheries biologist Graham Murrell told Ha-Shilth-Sa. “The rate has been about the same at the other counter.”
According DFO statistics, the fresh surge of sockeye surpassed 80,000 fish in aggregate through Monday, for a total of about 160,000, all told. Murrell said the 2015 Somass River sockeye run ramped up steadily until the prolonged hot, dry weather brought escapement to a crawl.
“Earlier in the run, we had a few good stretches [up to 5,000 fish per day], with cloudy skies, but late in June, it really started to taper off,” Murrell said. At that point, DFO, as recommended, shut down the river fishery as a conservation measure.
According to fisheries scientists, Pacific salmon are in danger when river temperatures reach 21 degrees Celsius and above. Prolonged exposure above 24 degrees has been considered a lethal dosage.
For the past few years, Somass system sockeye have regularly survived river temperatures above 21 degrees. During last week’s heat wave, however, those temperatures climbed to 25.9 degrees in the Sproat River, prompting that mass die-off.
“Our fisheries people are doing daily [mort] counts,” Murrell said. “I went up today (July 14). From the [Sproat River] bridge to the lake, there was minimum mortality, perhaps 300 fish. Around the fishway, it started to pick up, and below the fishway I counted four or five thousand.”
On Tuesday, Tseshaht fisheries biologist Andy Olsen travelled to Vancouver with an allotment of sockeye for members living on the Lower Mainland. These fish were caught by a contracted seiner in open water, in light of the river closure, he explained.
Apprised of Murrell’s mort count, Olsen said the die-off was predictable but not catastrophic.
“It’s not something we didn’t expect to happen, with low water, low oxygen and high temperatures,” Olsen said.
But, in part because of the abundant 2015 sockeye return (DFO’s pre-season estimate was 700,000 to one million fish), with the recent surge in escapement, both Sproat and Great Central Lakes have met their “biological benchmarks,” Olsen explained. Those are the minimum requirements for the survival of the run.
“But the thing people have to remember is that our goals are set for production, rather than just continuing the stock. Our goals are set artificially high to get high returns of sockeye back into the system.
“Our goal is 420,000 fish. That’s set for high returns in the future – 700,000 to 900,000 sockeye coming back for the fisheries. The minimum escapement is set at 60,000 for Sproat and 80,000 for Great Central. We’re at about 68 (thousand) and 86.”
So, with the current surge in escapement, the Somass sockeye run has moved beyond “survival” and is creeping towards “production,” according to the numbers.
While temperatures have cooled, however, the Alberni Valley only received about 1.6 millimetres of rain over the weekend. Had 2015 been an off year for sockeye abundance, the recent die-off could have had a far greater impact on stocks.
For that reason, Tseshaht has called on DFO for an emergency meeting to deal with drought conditions on Vancouver Island rivers (http://www.hashilthsa.com/news/2015-07-10/tseshaht-wants-emergency-meeting-dfo-drought).
Currently, Tseshaht and Hupacasath First Nations meet weekly with DFO as part of the Area 23 Round Table management group, as well as holding individual discussions on a weekly basis. Olsen said creating drought strategies with the federal government has been a “slow process.”
There is no question that DFO is determined to protect the fish, he was quick to add. That takes the form of setting conservative fishing targets and imposing preventative closures when conditions demand.
Olsen said, had DFO projected a less abundant run, they would have imposed fisheries closures much earlier.
“We would have had less fishing time at the beginning of the year,” he explained. “What tends to happen with lower returns is that ‘the back half’ doesn’t show up. Those are the fish that go up in July and August. It was the middle part of the run that got hardest hit.”
As a result, the fishing plan targeted that middle part of the run that would have seen the highest attrition in the river, and is allowing the later fish to have a “free pass up the river,” Olsen explained.
But other than managing lake levels to ensure adequate stream flows in the Stamp and Somass Rivers (the actual field work is performed by Catalyst Paper employees), DFO has not moved forward with any infrastructure initiatives to mitigate the effects of drought in the event that the unseasonably hot and dry conditions of spring/early summer 2015 become the “new normal,” Olsen said.
One long-discussed initiative is a system to siphon cold water from the depths of Great Central Lake both to increase stream flows and to lower temperatures in the system, when required.
“We’ve talked about it briefly, but for this year, the timing was too late to get it into our [meeting agenda]. But it is something we’ve had discussions [about]. We’re just trying to find out if it’s feasible, from the guys that did the research. Some of them say it isn’t, some of them say it is.”
In the meantime, conditions could continue to be stressful for migrating Somass system sockeye. On Tuesday, despite the water release and the cooler temperatures, the thermometer at the Sproat River fishway hit 24.2 degrees Celsius by 2 p.m.
“It normally peaks at around 6 to 7 p.m.,” Murrell said. “We expect it to hit about 24.5 today.”
Fortunately, the migration from the Somass Estuary to Sproat Lake is fairly short, Murrell noted, adding that temperatures in the longer Somass/Stamp River migration route are typically cooler than in the Sproat.
