Fisheries Department spokesman Hein Wyngaard says the reason for the mortality rate among sardines - known locally as pilchards - is the persistent red tide that extends from Walker Bay around the Cape Peninsula to St Helena Bay, Times Live reports.
The red tide is caused by the dinoflagellate Gonyaulax polygramma, a non-toxic species that has been linked to fish deaths because it depletes oxygen in the water as it decays, causing fish to suffocate.
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