By JOE FRIES
A popular South Okanagan fishing spot is under threat from an invasive species more often seen in backyard ponds and home aquariums.
Common goldfish have been introduced to picturesque Yellow Lake, located about 30 minutes southwest of Penticton on Highway 3A, and seem to be doing quite well there.
Penticton man Don Agnew hooked three of them in late November while casting for trout and Kokanee near the boat launch at the west end of the lake.
The retired heavy-equipment operator, who’s been angling in Yellow Lake for years, said he noticed a school of approximately 150 fish that were bright orange and silver in colour floating about six metres off shore.
After taking a closer look and realizing they weren’t regular game fish, he began casting a small, grey fly baited with a piece of worm into the school. It didn’t take long before he connected with one of the invaders.
“I was a little bit surprised, to say the least, but they’re a beautiful colour,” said Mr. Agnew. “They’re just iridescent – both the silver and the orange ones.”
The three he caught ranged in size from about 15 to 30 centimetres, a clear indication to him that they’ve been breeding in the lake, which is stocked annually by the Freshwater Fisheries Society of BC and plays host to regular learn-to-fish events.
Mr. Agnew killed the smaller one, but kept the larger two to show wildlife officials. He said he cut into the largest of the bunch and discovered thousands of eggs, each smaller than a pinhead.
“You get a couple dozen of them spawning, there won’t be much left,” he warned.
An official from the B.C. Environment Ministry confirmed the goldfish, based on the havoc they’ve wreaked in other jurisdictions, pose a grave threat to Yellow Lake.
“They have been shown to prey on native species in other areas where they’ve been introduced,” said Martina Beck, the ministry’s invasive species co-ordinator. “They can also disturb the sediment when they feed, so this can increase the water turbidity and it can harm aquatic plants and the aquatic environment.
“They also have a wide-ranging diet, so they can compete with native fish species for food, and they are known to withstand a wide range of temperature and oxygen levels and reproduce rapidly. That’s what made them successful in other regions.”
Ms. Beck said the ministry first learned of gold fish swimming in Yellow Lake in 2015, and is currently working on a B.C.-wide impact assessment for the species.
Yellow Lake is targeted for more detailed sampling of the gold fish population in the spring to help figure out what to do with them.
Ms. Beck said there’s no way to eradicate goldfish specifically, except by netting them.
She believes the species was intentionally placed into Yellow Lake.
“It is likely that it was a release from a pet aquarium owner, an unwanted pet. This is one of the most common ways they are introduced,” explained Beck.
“They can escape from outdoor ponds or aquariums, but that’s not likely in Yellow Lake.”
Mr. Agnew eventually threw away the goldfish after trying unsuccessfully to get someone to speak to him at the Environment Ministry office on Industrial Place in Penticton.
Ms. Beck encourages anyone who wants to report an invasive species to do so through the B.C. government’s website at www.gov.bv.ca/invasive-species, from which a new app can also be downloaded to identify such critters in the field.
She also cautioned people to think twice before releasing any kind of non-native creatures into the wild.
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