Shelly Creek Pit Tagging Project
"survival bottleneck" - an event that drastically reduces the size of a population.
Our last article talked about our participation in the PIT tagging program occurring on Vancouver Island as part of an investigation into "survival bottlenecks" of Coho and Chinook salmon and Steelhead trout populations to explain their drastic decline in the Salish Sea. We have expanded on that theme and begun a PIT tagging program of our own on the resident Cutthroat trout population in Shelly Creek. Our interest is in the migratory habits of this population which inhabits the section of creek that runs through Shelly Park (located at Corfield Street and Butler Ave in Parksville). How far does their home range extend in the creek? This is important to know if this unique population of Coastal Cutthroat Trout is to be protected. We also hope to learn if their movement through the creek is being obstructed by culverts, do any of the trout every migrate downstream into the Englishman River, and are there habitat conditions in the creek they avoid or prefer?
A Passive Integrated Transponder (PIT) tag is a very small cylindrical metal tag implanted into the abdomen of a juvenile fish. Each tag contains a unique code with information about the fish, like the species, age, date and location of where it was tagged. When a tagged fish swims over antenna arrays that have been installed across the bottom of a creek, the code is picked up and stored by the arrays so the movements of individuals can be tracked. MVIHES volunteer, Pete Law, applied for and received a grant from the Freshwater Fisheries Society of BC to purchase the equipment for assembling the antennae array that will track the tagged fish.
We realized early on that we needed some "young blood" involved in this study. Ally Badger, a Biology student at Vancouver Island University (VIU), has taken on this project as part of her studies for her degree. Since she is working for the BC Conservation Foundation (BCCF) who has been implanting PIT tags into Coho, Chinook and Steelhead fry, this seemed the perfect fit. The left-hand photo shows Thea Rodgers of BCCF, left, and Ally, right, preparing to implant tags as MVIHES volunteer David Erickson "supervises".
The right-hand photo shows MVIHES volunteers (Pete Law, upper left; Dick Dobler, lower left; and David Erickson, right) capturing trout for tagging using a pole seine net. The creek is now at its summer low flow condition so further tagging will resume in fall so the fish are not unduly stressed. To learn the results of the study, read Ally's report.
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