A large sturgeon was spotted floating on its back in the lower Fraser River recently with a juvenile sturgeon down its throat.
Given the possibility it was an act of cannibalism due to scarce food sources for white sturgeon in the Fraser right now, it’s a big concern, according to officials with the Fraser River Sturgeon Conservation Society.
Sturgeon tagger Colin Bond of Surrey made the discovery. He’s fished the Fraser for 30 years, and is also a volunteer for the Sturgeon Conservation Society, sampling and tagging the dinosaur fish for the society for more than a dozen years.
“I have seen many interesting and surprising sights, but I had never seen anything like this,” Bond said.
He launched his boat near the Golden Ears bridge on Feb. 5. He observed the extremely strange sight while motoring upstream near Fort Langley.
Moving in he saw it was large adult sturgeon, approximately 160 centimetres (nearly 6 feet) in fork length (FL), which is the measurement in a line from the tip of the fish’s nose, to the fork in the tail.
Protruding from the sturgeon’s mouth was the tail of a smaller, juvenile sturgeon. It was wedged in past the gums and down the throat of the larger fish.
“Neither fish was moving. The large fish appeared to be rather thin and skinny for its size. I circled around the fish and took a few pictures,” Bond said.
They were still, and appeared dead but they weren’t.
“Then suddenly the tail of the small fish started to twitch. It was alive!”
Bong had the sling in place. When he reached over the side of the boat and grabbed the sturgeon by its right pectoral fin, it jolted, appearing to come “back to life.”
The big fish jerked, thrashed and flipped over, with the smaller one still in its mouth.
“It swam off and then down, and out of sight. It came to the surface briefly and made one final splash, then went under, and I never saw either fish again,” Bond recounted.
Sturgeon Conservation Society officials say the whole episode is very concerning, given the decreased food supply issues in the Fraser right now, and relentless decline of white sturgeon numbers in the Fraser since 2006.
“This observation of possibly cannibalistic behaviour is a first for adult fish,” said Sarah Shreier, executive director of the Fraser River Sturgeon Conservation Society.
It comes on the heels of a stressed environment in the mighty Fraser.
“It’s a big concern for the overall health of the Fraser River,” she said. Research indicates the sturgeon population is projected to continue to decline unless the health of the river vastly improves.
“We know fish do this when there is a low food supply, and there is definitely low food for sturgeon in the Fraser given the issues with salmon and eulachon,” Shreier said. “So although we haven’t seen it before, it is possible due to those factors. Lots of other aquatic species also do this when they are short on food.”
They won’t ever know for sure.
Bond motored around looking to see if the fish had resurfaced after witnessing the rare sight. Eventually he continued upstream to his fishing location for the day, and when he returned downstream, he searched the banks of the river near the area where he‘d seen the pair of sturgeon.
“I did not see them again, Bond said, adding he hoped they survived.
“I know I will be keeping an eye out for a six-foot sturgeon with a very, very sore throat, and a smaller one with a serious headache.”
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