Daily seawater readings

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I used our herding board for the first time today. Ours isn’t red and I wasn’t moving little piglets. Ours is a sheet of plywood with two cupboard handles and I was trying to send the California sea lions off the Jetty so I could take the daily seawater reading. The surface seawater temperature and salinity data have been collected at Race Rocks since February 1921!

It is great to take part in this long-standing tradition and as a tribute, I wanted to share some information on Race Rocks and the other light stations on the BC coast, ranging from the most northerly station on Langara Island, Haida Gwaii to Race Rocks.  The only station with a longer data collection period is Departure Bay.

Location of lightstations. Source: BC Lightstation Sea-Surface Temperature

Data collection period. Source: BC Lightstation Sea-Surface Temperature

Race Rocks and Pine Island are different from the other stations in that they show the least amount of seasonal variation and have the flattest curves of monthly average temperatures over the past 30 years. These two stations also have lower temperatures than the other stations in their geographic areas.

Monthly temperatures from 1991-2020. Source: BC Lightstation Sea-Surface Temperature

Temperatures at lightstations grouped by geographic area. Source: State of the Physical, Biological and Selected Fishery Resources of Pacific Canadian Marine Ecosystems in 2022, page 44

At Race Rocks the temperature increases have been greatest in the most recent period ranging from 1994 to 2023. And one last pretty graph… a plot of daily temperatures for the 2023 data for Race Rocks, showing the months that were colder or warmer than expected.

Graph of daily temperature observations for Race Rocks. Source: BC Lightstation Sea-Surface Temperature

Daily temperature observations at Race Rocks for 2023. Source: BC Lightstation Sea-Surface Temperature

Sea surface temperature in B.C. waters has been increasing over the long term and salinity in the NE Pacific has decreased in recent years. It is of great concern. To learn more about the implications of rising ocean temperatures and salinity changes and Canada’s oceans in general (in order of increasing detail and scientific complexity):

Wildlife notes:

The entangled sea lion moved yesterday to Middle Rock and was not seen on Great Race Rocks today. No out-of-the-ordinary wildlife sightings today.

Facility work:

  • Cleaned solar panels
  • Operation walkway – work in progress

Vessels:

  • 16 Ecotourism, 1 private

Weather:

  • Overcast until late afternoon. Winds westerly varying from moderate to strong breeze. Daytime temperatures: low 13, high 17.