Red tide suffocating pilchards

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.

For more:

• Times Live: Cape Sardines forced ashore