The recent red tide, which caused hundreds of tonnes of West Coast rock lobster to walk out of the sea, has dealt another blow to vulnerable fishing communities along the West Coast.
The fishing industry is one of the area’s economic mainstays, worth more than R500 million and directly employing over 4,200 people. However, it is now feared that the red tide will further damage already depleted fishing stocks.
The red tide, which is caused by an algal bloom in the coastal waters, has led to about 500 tonnes of West Coast rock lobster being thrown away this month.
An algal bloom is the overgrowth of microscopic algae in the water. When the algae die and decompose, they consume all the oxygen and cause water breathing animals to flee for their lives, even going so far as to walk out of the water in search of oxygen.
According to Cape Nature Marine and Coasts operations senior manager Pierre de Villiers, the “walkout” of the lobster should be treated as a disaster similar in nature to an oil spill or a fire.
According to Albi Modise, spokesperson for the department of forestry and fisheries, there have been no reports of new walkouts of the West Coast rock lobster on the West Coast of the Western Cape, since last week (5 March, 2022). However, the chances of more lobsters walking out of the water or other marine life dying because of anoxic conditions (oxygen depletion) in the water remain high for the foreseeable future.
Satellite imagery shows that there is still a lot of algae biomass between Cape Town and Paternoster, as well as along the coast between Lambert’s Bay and Doring Bay. Warm weather and light winds are expected to contribute to elevated red tide risks along most of the west coast over the next few days.
Not safe for consumption
Beach cleaning operations are still underway, with approximately 30 tonnes of live lobster being returned to the sea. These lobsters pose no danger to humans or marine life.
However, Lobsters that have walked out and died on the beach pose a risk because they rot quickly after death and lie in the sun on the beach. This is why the general public is not permitted to collect washed-up rock lobsters, or other fish.
The algae that cause red tide can grow too much and make toxic compounds that are dangerous if ingested. People and animals get very sick when they eat food or drink water that has been contaminated by this harmful algae. This can also harm the environment and kill fish.
The red tide is monitored by a group of people in the department of forestry, fisheries, and the environment. They use the fisheries and Aquaculture Decision Support Tools that are available on the Oceans and Coastal Information Management System (OCIMS) web portal (www.ocean.gov.za).
Between 10 and 28 February 2022, satellite images showed a bloom of algae in the St. Helena and Elands bays. It took a long time for the algae to die and break down, which took oxygen from the water. This made the water so low in oxygen that the animals even walked out of the water in a desperate attempt of finding oxygen to breathe.
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