A harmful algal bloom – also known as a red tide – has been building up at Elands Bay on the west coast of South Africa resulting in several marine species washing up on the beach.
These include rock lobsters, octopus, white mussels and some fish species.
“Red tides are a natural phenomenon in coastal waters caused by a dense accumulation of microscopic algae. Some of the algal species are harmful because they contain toxins, which are poisonous to humans,” the Department of Environment, Forestry and Fisheries said on Sunday.
Other red tides cause harm through the depletion of oxygen (anoxia), which affects all marine creatures and can lead to mass mortalities of the entire marine communities or mass walkouts of rock lobsters that try to escape the anoxic conditions.
The department said weather conditions are not favourable at the moment as a north westerly (NW) wind is currently blowing and keeping the algal bloom concentrated in the bay.
“Notwithstanding the red tides, west coast rock lobster catches are still good and this indicates that oxygen levels are still high. The new moon spring tide occurred two days ago, thus limiting the possibility of a mass stranding within the next 10 days,” the department said.
The department has immediately activated the West Coast Rock Lobster Contingency Plan and issued a Situation Yellow Alert, placing all government roleplayers on standby.
In terms of the contingency plan, the Department of Environment, Forestry and Fisheries is the lead department, supported by West Coast District Municipality, Cederberg Municipality, South African Police Services, SANDF and Western Cape Province.
These roleplayers are currently preparing for a Situation Red because beaching has taken place and there is a possibility that there may be beaching in excess of 10 tons at a single or multiple localities in the area
“As is often the case in summer and late summer, there has been a build-up of large Red Tides in the greater St. Helena Bay region over the past few weeks.
These blooms of phytoplankton presently extend 50-60 kilometres in the vicinity of Elands Bay, Lambert’s Bay and Doring Bay,” the department said.
Photo: Cederberg Municipality