A Red Tide is a higher-than-normal concentration of a microscopic alga (plant-like organisms). In Florida, the species that causes most red tides is Karenia brevis. This organism produces a toxin that can affect the central nervous system of fish. At high concentrations (called a bloom); the organisms may discolour the water. However, red tides are not always red. They can appear greenish, brownish, and even purple in colour. The water can even remain its normal colour during a bloom.
Unfortunately with fish and other marine mammals even to the size of a manatee, the algae dissolves the oxygen in the water and the fish therefore are unable to breath and die quickly being washed up onto the beach.
Some people can be affected by the bloom in the water especially those who are either asthmatics or prone to chest complaints. Walking on a jetty or pier towards the sea when Red Tide is present can mean a tightness of the throat and chest literally occurring step by step. Retreat from the area and the feeling will soon go away. Over the counter antihistamines will help any lingering problems. There have never been any reports of deaths from Red Tide and theoretically it is still safe to swim although there may be a burning sensation to the skin.
Red Tides cannot be predicted but local authorities will erect notices at the beach when the area is affected by Red Tide – the first indication of the bloom being present is the lack of bird life at the beach area as the birds are slightly affected but of course their food stock is depleted.
Red Tide is not something to be ‘expected’ during your beach holiday, it can be absent for several years without appearing but Red Tide can lasts for days, weeks or even months but generally a week to ten days is the normal period in the Gulf of Mexico. Local authorities will erect notices at the beach area if Red Tide is present.
Restaurants will obtain their fish from non-Red Tide areas so there is no problem in ordering fish from a menu however it is not recommended that freely caught molluscs are eaten.
Mote Marine Laboratory in Sarasota is a world renowned establishment into the research of Red Tide and its effects on marine life.
Regrettably I fear Red Tide is just one of the things that the Gulf of Mexico coast has to put up with as it was as long ago as the 1800’s when it was first documented and is still with us today.