Sentinels of Change
CHI volunteers check the light trap 3 times a week and report their findings back to Hakai Institute.
Sentinels of Change is a new initiative on Hornby run by the Hakai Institute as part of a decade-long community-centered initiative investigating patterns of invertebrate biodiversity, change, and resilience across the Salish Sea.
Amanda Zielinski heads up the Hornby effort. It is one of 25 in the Salish Sea and Juan de Fuca, and builds on the earlier work done by the light traps network in Puget Sound. The project consists of community scientist volunteers monitoring light traps that run in the early morning darkness and attract larvae. The focus is on Dungeness crab megalopae (crabs in their early stages). The trap is monitored three times weekly, once by Amanda, once by the Natural History group and once by Conservancy Hornby Island. Amanda sets the timer that controls how long the light runs, cleans out the trap, trains the rest of us, houses the equipment and generally oversees the operation of the Ford Cove trap. Larvae attracted by the light enter the trap through funnels and when the trap is lifted out of the water, they end up down in the bottom part (the “cod”) which we can then gently tip into a bucket of seawater to examine our “catch”. The trap will be in the water for four months.
The interesting part is seeing what has been caught, and how it changes from week to week. Our (CHI group) first time monitoring, April 21st had loads of Polychaete worms, and was thick with tiny herring in the form of translucent swimming threads with two dark eyes. On April 28th there were only two worms, two herring, lots of amphipods (tiny crustacean), shrimp, and other small larvae darting around. May 5th we had a tiny jellyfish, some darting dark small fish, and two magalopae – which we were excited about. Turned out (upon expert consultation) to be the wrong sort of crabs – not Dungeness, but the first we’d clearly seen.
Lest you worry about the tiny creatures we examine and report on, we do release them back into the water.
If you find yourself down on the Ford Cove Dock around 9 a.m. on Tuesdays, Thursdays and Saturdays, and you see people hauling out a trap or poring over a bucket, you are welcome to have a close look at the marine creatures too small to otherwise see in our corner of the Salish Sea.
If you would like to volunteer, please contact CHI, Hornby Natural History, or Amanda Zielinski info@hornbyislanddiving.com.
To learn more about the project, visit https://sentinels.hakai.org
By Joanne Wyvill for CHI