Increased drought periods could result in serious consequences on salmon returns over the next 50 years

Increased drought periods could result in serious consequences on salmon returns over the next 50 years

Dry summers paint dim picture for returning salmon

Increased drought periods could result in serious consequences on salmon returns over the next 50 years, say scientists.

Every year since there were mountains, rivers and oceans, salmon have always made their way back from the salty sea to spawn another generation in local streams.

Something’s changed though. Mother Nature’s modus operandi is off its axis, and this year’s abnormally dry summer paints a concerning future for salmon returns across the Island.

As such, the number of drought days has gone from very few to 100-plus every year, a staggering change considering droughts of this size occurred once every 10 years, said Wilf Luedke, chief biologist for stock assessment on the south coast for the Department of Fisheries.

“We wonder, where does it end? The more days of drought we have, the more it changes the ecosystem, stresses the fish out,” Luedke said, adding that while the trend is unfavorable, every year we seem to “dodge the bullet” just in time, such as this year, thanks to a rainy September.

“If this trend continues then we’ll wonder, when does the rain start, are we going to have rain by October, maybe, maybe not? This isn’t a matter that extends into the next five years, but the next 50 years.”

Most vulnerable are coho, which stay in the system for a year as small fish before they go out to sea. If the water level is low and rivers dry up, they get stuck in little pools that can go up to 25 C, which can be lethal. Chinook face a similar risk, especially in systems that don’t have a lake behind them or some kind of weir control, such as Goldstream and Chemainus rivers.

Still, both salmon species are susceptible the same domino effect which stems from drought, lack of food in particular. If a river is dry for a month, all the insect colonies living under the gravel die off, leaving a gap in food supply when the salmon pass through.

Luedke explained that chinook on southern Vancouver Island would be affected in their adult migration depending on when the lay their eggs, which is typically between January and February, then they are out by June or July. With less snowfall and more rain, however, water temperature is warmer, causing the eggs to hatch early and go up to the ocean quicker.

This, in turn, throws off the whole timing process.

“For eons, they [chinook] were supposed to get out of there in May, find the plankton in the ocean, now they’re going out in March,” Luedke said. “Question is: Will there be the same food supply there that they evolved to?”

In the end, Luedke said DFO is working with local groups in the province on how to monitor and manage water supply. The big concern now is over any river that has a flow control, which most of the major rivers on Vancouver Island.

“Water conservation and water management is critical to maintaining the salmon runs,” he said.

Human development, such as logging, has affected salmon returns as well, as clear-cut areas no longer have vegetation to absorb the water, allowing it to travel down into rivers much faster, causing gravel to enter streams, which further disrupts salmon.

Looking at the larger picture, success of salmon runs will vary depending on the community and its location on the Island.

Sooke fisher Ron Neitsch, a fishing charter operator in Sooke for over 20 years, feels this year’s salmon returns were a mixed bag, as chinook returns were quite good, but the coho were not.

“We had decent water levels, Sooke Salmon Enhancement was able to intercept the chinooks on time, there were some that got into higher water before schedule, although it was still very successful with large salmons,” Neitsch said, adding that the local fishing community has seen drier falls than this one.

As for coho, Neitsch said possible reasons why they were less successful is because of a pattern that may had affected its spawn three years ago (since coho are three-year fish) such as floods that may have washed all the eggs away. He added that coho were far less out in the Strait of Juan de Fuca this year as well.

In the end, it still comes down to Mother Nature.

 

“Unfortunately, through all our wisdom, even with our 20 to 40 years of fishing experience, it’s usually a wait and see thing. Nobody expected this year to be that great for chinooks, yet it was,” Neitsch said.

 

 

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Highway 14 (Sooke Road) is closed between Impala Road and Humpback Road following a “major” police incident, according to DriveBC. (Black Press Media file photo)
UPDATED: Major crimes unit takes over after police incident closes Highway 14 through Sooke

Incident occurred Friday night, detour made available early Saturday

(Black Press Media file photo)
Get the word on art on Sunday afternoons in Victoria

Art Gallery of Greater Victoria presents Sunday lecture series in March

Community members Ed Hutchinson, left, Dave Noren, and Pat Graham, president of The Ladies Guild, stand before the new book house outside the Church of the Advent in Colwood. The tiny library was built as a result of the annual Church of the Advent book sale being cancelled due to COVID-19. (Submitted/Joan Hoffman)
Colwood church builds little library

Church of Advent annual book sale cancelled due to health restrictions

To each their own pipe. The new sewer main during staging in James Bay before it was installed in 2018, to convey waste to the McLoughlin Point treatment facility. (Black Press Media file photo)
‘End in sight,’ for Victoria’s annual sewage overflows

Wastewater projects underway should end sewage overflows

(Courtesy Very Good Butchers)
Very Good Butchers brand adds cheese to its platter

The Cultured Nut products to be rebranded under Very Good Cheese banner

The James C Richardson Pipe Band marches in a Remembrance Day parade on Nov. 11, 2019 in Chilliwack. Wednesday, March 10 is International Bagpipe Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of March 7 to 13

International Bagpipe Day, Wash Your Nose Day and Kidney Day are all coming up this week

More than ever before, as pandemic conditions persist, the threat of data breaches and cyberattacks continues to grow, according to SFU professor Michael Parent. (Pixabay photo)
SFU expert unveils 5 ways the COVID-19 pandemic has forever changed cybersecurity

Recognizing these changes is the first in a series of steps to mitigate them once the pandemic ends, and before the next: Michael Parent

Kevin Haughton is the founder/technologist of Courtenay-based Clearflo Solutions. Scott Stanfield photo
Islander aims Clearflo clean drinking water system at Canada’s remote communities

Entrepreneur $300,000 mobile system can produce 50,000 litres of water in a day, via solar energy

Malawian police guard AstraZeneca COVID-19 vaccines after the shipment arrived in Lilongwe, Malawi, Friday March 5, 2021. Canada is expecting its first shipments of AstraZeneca vaccine next week. (Associated Press/Thoko Chikondi)
B.C.’s daily COVID-19 cases climb to 634 Friday, four more deaths

Currently 255 people in hospital, 66 in intensive care

A crashed helicopter is seen near Mt. Gardner on Bowen Island on Friday March 5, 2021. Two people were taken to hospital in serious but stable condition after the crash. (Irene Paulus/contributed)
2 people in serious condition after helicopter goes down on Bowen Island

Unclear how many passengers aboard and unclear where the helicopter was going

Surrey Pretrial in Newton. (Photo: Tom Zytaruk)
B.C. transgender inmate to get human rights hearing after being held in mostly male jail

B.C. Human Rights Tribunal member Amber Prince on March 3 dismissed the pretrial’s application to have Makayla Sandve’s complaint dismissed

Supporters rally outside court as Pastor James Coates of GraceLife Church is in court to appeal bail conditions, after he was arrested for holding day services in violation of COVID-19 rules, in Edmonton, Alta., on Thursday March 4, 2021. THE CANADIAN PRESS/Jason Franson
‘Law remains valid:’ Pastor accused of violating health orders to remain in jail

The Justice Centre for Constitutional Freedoms is representing the pastor

The Netflix logo on an iPhone. B.C. delayed imposing sales tax on digital services and sweetened carbonated beverages as part of its response to COVID-19. Those taxes take effect April 1, 2021. THE CANADIAN PRESS/AP, Matt Rourke
B.C. applies 7% sales tax on streaming, vaping, sweet drinks April 1

Measures from 2020 budget were delayed due to COVID-19

A lawyer wears a face mask and gloves to curb the spread of COVID-19 while waiting to enter B.C. Supreme Court, in Vancouver, B.C., Friday, Aug. 28, 2020. British Columbia’s highest court has sided with the land owner in a dispute over public access to public land. THE CANADIAN PRESS/Darryl Dyck
B.C. high court finds in favour of large landowner in fight over access to pair of lakes

The Nicola Valley Fish and Game Club launched legal action after the cattle company blocked road and trail access

Most Read