Did these fish die because of high temperatures?

A viral Facebook video shows thousands of dead salmon floating on a river surface, while claiming in the caption that unusually high seasonal temperatures are to blame for the fish’s deaths.

The video is real, but its author misinterpreted the cause of death.

In late July 2019, a fishing boat’s net ripped and released hundreds of salmon into an Alaska river, a local aquaculture association told AFP.

“Unfortunately, the incredibly warm and sunny summer in Alaska has a dark face. This is how salmon died after the entering Tutka Lagoon in Kachemak Bay State Park near Homer,” a Czech tourist in Alaska wrote as a caption to a video uploaded on August 6, 2019. In the video, shot from a kayak, hundreds of salmon float lifelessly on the surface of the water as the raft paddles through the carcasses.

The Czech man’s video was shared more than 115,000 times, and uploaded by other users in French, Spanish, and Portuguese, gaining traction in those languages as well.

Although the video is real and the context is correct, these Pacific salmons were not killed by warm weather.

According to a clarification post published

by the Cook Inlet Aquaculture Association (CIAA), the salmon had been fished by purse seine, a large net that encircles schools of fish, in Tutka Bay Lagoon, in Kachemak Bay, four hours south of Anchorage by car. “The bottom of the net snagged on something and ripped,” the post described.

Dean Day, executive director of CIAA, confirmed the post to AFP by email, adding, “This is not a regular occurence.”

“Salmon that were caught in a purse seine that was being taken to a tender had the net hang up, this caused fish to spill out from the net and those fish (that were destined for the processor) did not survive,” Day explained.

The salmon were raised and released in the ocean by CIAA, which licensed a contractor to harvest a portion of the fish once they returned to Kachemak Bay.

Warmest summer on record in Alaska
July 2019 was the hottest month in Alaska since the National Oceanic and Atmospheric Administration (NOAA) began keeping records in 2005, the US government agency announced on August 15. The unprecedented heat wave killed many salmon in Alaska this summer, CNN reported.