Mystery of the Red Tide l 



By F. G. Walton Smith 



Vice President, The International Oceanographic Foundation 

 Coral Gables, Fla. 



[With four plates] 



One of the commonest and yet most baffling problems of marine 

 science underlies the red tide which has killed millions of fishes off 

 the west coast of Florida in past years. Temporarily, it caused physi- 

 cians' offices to be swamped with patients suffering from the accom- 

 panying windborne irritant gas. Mounds of dead fish covered the 

 beaches for miles and had to be bulldozed and buried in order to re- 

 move their stench. The effect on the tourist industry alone was serious 

 enough to awaken both State and Federal governments to its economic 

 importance and eventually to set teams of scientists to work in a con- 

 centrated effort to solve the problem. What caused the sea to change 

 color, fish to die, and visitors to develop sore throats % Marine biolo- 

 gists and oceanographers are following up all possible clues in an 

 attempt to unravel the mystery and to control its devastating effects. 



MANY COLORS 



From the earliest clays man has viewed with surprise and, at times, 

 with awe the sudden appearance of a vivid discoloration in the natural 

 waters of lakes and the sea. 



Nearly always the cause turns out to be a rapid growth or "bloom" 

 of microscopic water life, normally present in comparatively small 

 numbers, but under certain circumstances growing and reproducing 

 at an excessive rate until it is presently in very heavy concentrations — 

 sufficient to affect the color, feel, taste, and smell of the water and 

 sometimes, though not always, to render it poisonous to the fish in- 

 habiting it. 



A WORLD-WIDE PLAGUE 



In the early fall, along the western coast of Japan, patches of water 

 frequently become brown in color and oily in appearance, owing to 



Reprinted by permission from Sea Frontiers, Bulletin of the International 

 Oceanographic Foundation, vol. 3, No. 1, March 1957. Unless otherwise credited, 

 photographs by courtesy of Sea Frontiers. 



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