In Malahat Drive in BC, an extraordinary heat wave, combined with low tides during the middle of the day resulted in the die off of possibly billions of intertidal invertebrates along the coast of British Columbia and Washington State.
Although some trace intertidal odors can be detected while travelling along Malahat Drive at times, I observed an unusually strong stink of rotting intertidal life during the last week of June 2021. During this time the area was hit with significantly high and unseasonal temperatures, with some areas approaching 40°C during the peak of the heat wave on June 28th (Environment Canada, 2021). The extraordinary heat wave, combined with low tides during the middle of the day resulted in the die off of possibly billions of intertidal invertebrates along the coast of British Columbia and Washington State (Migdal, 2021). This observation stood out to me because extreme heat similar to what was experienced during the last week of June 2021 will become more common due to climate change (Ekins et al., 2019). Philip et al. (2021) estimate that in a world with 2°C of global warming, heat events like the one experienced during the 2021 heat wave could occur every five to ten years along the coast of British Columbia.
We are still learning about the long-lasting impacts that these extremely warm days have on the marine invertebrates of the pacific northwest. In an interview with KUOW News, UBC Biologist Chris Harley notes “The balance is going to be how long is recovery versus how long until the next severe heat wave...if the heat waves start happening more rapidly than the recovery time, that's when you will start seeing really big changes in what the shoreline ecosystems look like that are more permanent.” (Ryan, 2021). With respect to our most recent heat wave, the impacts to the people that rely of shellfish have lasted far beyond the few days when the heat wave occurred. For example, the impacts that the heatwave had on the livelihoods of shellfish farmers in British Columbia has been unprecedented and catastrophic, with some farmers reporting up to 100% mortality (Baker, 2021). Some say it will take three to four years before their businesses can recover (Dandekar, 2021). Conversely, deep water stocks propagated by larger operations were better sheltered during the heatwave by cooler waters away from the shoreline (Hagenbuch, 2021).