378 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1957 



tide year a succession of such outbreaks at different parts of the 

 coast may occur with varying intervals of time. 



What was the connection between successive outbreaks ? In order to 

 prevent the death of fish by poisoning "Jim Brevis" before it could 

 bloom, it now seemed clear that not only must the first outbreak be 

 predicted but it must also be possible to predict the pattern of future 

 successive outbreaks. These were the tasks undertaken by the Miami 

 oceanographers. 



A NEW LINE OF ATTACK 



First, records of all past outbreaks were examined in great detail. 

 They suggested that when one or perhaps several patches of water be- 

 come suitable for a red-tide outbreak they might be carried by the 

 system of water currents to other parts of the coast. This new way of 

 attacking the problem has finally given a clue to the prediction of 

 red tides. 



The fully equipped seagoing research vessel Gerda (see article in 

 vol. 2, No. 2, of Sea Frontiers), with all the latest types of apparatus 

 for studying conditions at sea, left Miami for the west coast of 

 Florida. Under the direction of oceanographers Ilmo Hela and 

 Frank Chew, there began a long and exacting study of the water 

 currents and tides in every detail. By working night and day while 

 out at sea they accumulated a prodigious amount of data. Back at 

 the laboratory, samples of sea water were examined chemically and 

 the long task of mathematical analysis began. 



A SCIENTIFIC FLEET 



Results were checked and analyzed by the use of free drifting 

 buoys and floating cards, whose travel between the time of dropping 

 in the water and the time and place where found gave further evi- 

 dence of water movement. On occasions a large fleet of yachtsmen, 

 fishermen, and power-squadron members cooperated by dropping 

 cards, identified by numbers, in the waters at numerous places simul- 

 taneously. Several days later they returned to locate the cards, floating 

 in their sealed plastic covers. 



The complicated pattern of currents changes somewhat with the 

 season of the year, so that it was necessary to repeat the work at sea 

 on a number of occasions. But the interlocking system of currents that 

 gradually unfolded showed how red tide could, apparently haphaz- 

 ardly, jump from place to place, as the affected water was carried 

 along. This led to the next stage in the attempt to predict red tides. 



WHAT MAKES WATER MIX 



Water flowing in tides and currents and acted upon by wind and 

 wave tends to mix and this would tend to disperse red-tide water. If 



