Concentrations are currently low. Researchers are monitoring the site after a 2020 bloom caused mass marine-animal deaths.
Researchers have detected the dinoflagellates Karenia cf. breve and Karenia cf. selliformis in Avacha Bay for the first time during regular monitoring. The organisms were found on October 2, 2026, in surface waters of Rakovaya Bay, the Kamchatka branch of the Russian fisheries research institute said. Monitoring in Avacha Bay has been conducted since 2013.
Concentrations remain low, at 2,000 to 8,000 cells per liter. Scientists are continuing to monitor conditions but say they cannot yet predict how the situation will develop.
The finding is drawing attention because a Karenia bloom in autumn 2020 was followed by mass deaths of bottom-dwelling marine animals off Kamchatka. Mussels, sea urchins, octopuses and other species washed ashore. Researchers later found damage to commercial whelk grounds in the Sea of Okhotsk. A peer-reviewed study of the 2020 event also documented severe harm to marine life from the harmful bloom. The current detection at low concentrations does not by itself mean the 2020 scenario is repeating.