From playing the saxophone and swimming with surfers to attacking children, the gray seals of South Africa have gone from the most loved to the most feared in mere weeks. From a reported attack on a child on Clifton Beach on the third day of January to chasing a vacationer off the beach in Jeffreys Bay, multiple seal attacks are reported in major coastal towns along the coastline of South Africa.
The recent change towards aggression in the seals is attributed to the red algae bloom. A specific diatom called Pseudo-nitzschia and photosynthetic plankton is the culprit in question.
The diatom releases a chemical known as domoic acid.
Domoic acid has dangerous and even deadly effects on marine life, such as:
Death in fish due to toxins and a lack of oxygen in the surrounding water.
Long-term neurological damage due to swelling in the brain of larger sea mammals
High levels of confusion and aggressive behavior
In areas of coastal upwelling, such as at Benguela Cove near Cape Town, red tide or harmful algae blooms (HAB) are common occurrences. HAB occurs due to a spike in nutrients in the water that allows the algae to bloom uncontrollably. A dense mass of this algae occurs and subsequently covers the ocean, best described as a thick red blanket. In extreme cases, the ocean seems to turn bright red.
The red tide is traceable as far back as the Spanish exploration of the 15th-century when Cabeza de Vaca first reported the phenomenon of a red sea and unexplained masses of dead fish. Since then, the frequency of the occurrences has only increased.
When asked what the cause of the rise in the frequency of the red tides is, Richard Stumpf, an algal bloom expert, stated that "the rise in nutrients running into the oceans from land and climate change are mostly to blame." Stumpf spoke about the change in weather and its effect during an interview with National Geographic.
NSIR in all coastal towns has issued warnings against approaching any beach animal, as the risk of an aggressive attack is imminent. The internet is buzzing with video footage of seals behaving out of the ordinary and attacking people even when unprovoked.
Aaron Barnes, a researcher for Sea Search and Conservation, stated that they ‘have noticed the behavior change and are launching an investigation.’
No cure is currently known to save marine life. As concerns for the well-being of seals increase, scientists hope that more substantial treatments will be discovered in the future to reverse the effects of domoic acid on all marine life.
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