Recently in Bali there was a ‘Red Tide’ causing a lot of dead fish to be washed to the shores along the tourist strip of Kuta coast. The beaches literally stunk and the tourists weren’t impressed and neither were the locals. It is a phenomena that has been around for centuries and will continue again in the future according to scientists. Red tide is a natural phenomenon caused by algae blooms of reddish-brown phytoplankton (microscopic algae) in the sea, often in coastal waters. Most red tides are harmless, but a few species of phytoplankton cause red tides that are poisonous to marine animals and humans.
The phenomenon usually occurs six months to a year after the El Nino phenomenon, which kills plankton and causes the emergence of a poisonous plankton. Human beings are advised not to eat fish that die because of red tide as it may cause diarrhoea or even death.
The red tide phenomenon in Bali is said to occur every four to five years. Scientists recorded that the event happened in 1994, 1998 and 2003.
“Red Tide” is a common name for a phenomenon known as an algal bloom, an event in which estuarine, marine, or fresh water algae accumulate rapidly in the water column, or “bloom”. These algae, more specifically phytoplankton, are microscopic, single-celled protists, plant-like organisms that can form dense, visible patches near the water’s surface. Certain species of phytoplankton contain photosynthetic pigments that vary in color from green to brown to red, and when the algae are present in high concentrations, the water appears to be discolored or murky, varying in color from white to almost black, normally being red or brown. Not all algal blooms are dense enough to cause water discoloration, and not all discolored waters associated with algal blooms are red. Additionally, red tides are not typically associated with tidal movement of water, hence the preference among scientists to use the term algal bloom.
The most conspicuous effects of red tides are the associated wildlife mortalities among marine and coastal species of fish, birds, marine mammals and other organisms. In the case of Florida red tides, these mortalities are caused by exposure to a potent neurotoxin called brevetoxin which is produced naturally by the marine algae Karenia brevis (wikipedia)
So, there you have it, a natural environmental and scientific explanation. Let’s hope that there are no more red tides in the future because it does upset the tourists to a certain degree.