In 2016, the Nechako White Sturgeon Recovery Initiative began to suspect River Otters were consuming the juvenile Sturgeon that were being released in an attempt to boost their population.
This week, UNBC Masters of Science and Biology student, Cale Babey presented a paper at the North American Sturgeon and Paddlefish Society conference that dives into the issue.
“The Nechako White Sturgeon is an endangered species, so this conservation program for releasing fish into the river is a pretty important step in conservation efforts right now,” noted Babey,” the survival of those fish is very important.”
For the last two years, Babey has been studying Otter predation on the fish in the Nechako River in Vanderhoof.
To supplement his research, every Sturgeon released into the river was given a microchip (PIT tag) with a unique number that can be read by a special reader.
“When an Otter eats a Stugeron he ends up ingesting one of these little PIT tags,” said Babey, “we then scan the Otter defecation to determine how many of these PIT tags are being eaten.”
He visited dozens of areas along the Nechako River, and researchers collected 1,170 juvenile sturgeon PIT tags from 59 identified sites, including 524 tags collected between 2016 and 2019.
“We have evidence now that over 1,000 of these Sturgeon have been eaten by River Otters,” he added.
The PIT tags also tell researchers what year the fish was released into the river and what area they were released into.
Babey explained that any information on post-release mortality is important, and was a key identifier in understanding how serious the issue of Otter predation is in the river.
His paper is published in the Journal of Applied Ichthyology, where information on the branch of zoology that deals with fish is presented.