A Puget Sound scientist’s work is never done. PSI’s Lead Ecosystem Ecologist Tessa Francis sent us this e-mail about a recent call to identify some wayward fish on Vashon Island. It didn’t hurt that she happens to study the same species of fish — Pacific herring — as part of her research at PSI.
By Tessa Francis
Two days into the New Year I got a text at lunch from Vashon Island Nature Center staff with a picture of dozens of fish in a pool: ‘Wondering if you could tell what kind of fish these are? They seem to be trapped.’ They were in a tidal creek that had become isolated from the main Puget Sound at low tide. The staff was worried the tributary wouldn’t be reconnected at the next high tide, and were planning to manually move the small fish back to the open water. After seeing a close-up picture (and after confirming my ID with a WA Department of Fish and Wildlife colleague – better safe than sorry!), I told them they had Pacific herring (Clupea pallasii) on their hands, probably 2-year olds, given the size.
Historically, herring have spawned annually on Vashon Island, all along the shores of the Quartermaster Harbor bay, but their numbers have been very low in recent years. Work from a group I am co-chairing as part of the Ocean Modeling Forum suggests that when populations of herring are on average young (like these 2-year olds), they have a more difficult time finding their way back to their spawning grounds. In any case, it is just about the window of time when the Quartermaster herring start their spawning, and while it is not exactly clear whether these fish would be spawning this year (only about 1/2 of 2-year olds are mature), it was interesting to see them hanging around the island.
The volunteers then moved 130 fish by hand, aiding them on their journey. If indeed these fish were making their way to the Quartermaster spawning site, they still had the circumnavigation of Maury Island ahead of them!