Even throwing salmon carcasses into streams must be done differently in the age of COVID-19.
The annual Salmon Carcass Transplant went ahead this year, but with a significantly reduced number of salmon-throwers. The normal, public event was cancelled, but with help from Saanich Parks Urban Forestry workers, the carcasses arrived at Douglas Creek on Jan. 22.
“When salmon return and spawn, they die and that is actually ecologically quite good,” explains organizer Darrell Wick, president of the Friends of Mount Douglas Park Society. “The salmon bodies really provide nutrients and fertilizer for our nutrient-void streams.”
During the annual transplant event, the carcasses, provided by the Goldstream (Howard English) Hatchery, are thrown into the top of the Mount Douglas Park stream – mimicking the natural spawning patterns of salmon, who return to their birthplace to spawn and, ultimately, die. The fish are eaten by birds, raccoons and other critters, and the remaining pieces continue to decay, spreading nutrients downstream.
As animals drag the fish carcasses to the shore, or defecate after a salmon carcass meal, they enrich the soil with the carcass nutrients. Tree core samples near spawning streams have shown traces of mineral samples from the sea, Wick notes, an example of how far the ecological benefits of salmon decay reach.
|The 2021 Salmon Carcass Transplant event went ahead without the public’s participation this year. The decaying fish play a vital role in the vitality of regional streams, soil, trees and animals. (Photo Courtesy Darrell Wick)|
In a typical year, the event is centred on both ecology and education, teaching the public about pollutants and other risks to the stream and its species.
Currently, the biggest challenge to the stream is heavy rainfall and impervious surfaces, like pavement, across Saanich. Without absorbent surfaces, rainfall makes its way to storm drains before being directed to local streams.
A surge of rainwater can erode spawning beds, damage the creek and wash out vital species. And Douglas Creek, at this time, simply doesn’t get a big enough salmon return, Wick says. That’s why another part of the efforts is to bring in salmon eggs, in hopes the hatchlings will imprint on the stream and return there several years later to spawn.
This year, there wasn’t enough eggs for the group to hatch at Douglas Creek, but the carcasses were doing their job within hours of arriving.
“Out of 120 I saw 10 that had already been partially eaten in under 24 hours,” Wick said.