at a symposium of specialists in marine 

 biology held at the Galveston Biological 

 Laboratory on March 5-7, 1958. It was 

 agreed that an intensive field study in a 

 smaller geographic area might lead to 

 a better understanding of red tide out- 

 breaks. 



Most of the station locations are 

 in areas in which high concentrations of 

 G. breve have been observed. During 

 the period of this report two outbreaks 

 of red tide occurred. The first, com- 

 mencing in 1957 and lasting from the 

 end of September through December, 

 occurred chiefly in coastal waters and 

 bays from Anclote Key south to the 

 Shark River in the Florida Everglades. 

 River mouths were affected to a lesser 

 degree. The second outbreak occurred 

 during September through December 

 of 1959 in the coastal area between 

 St. Petersburg Beach and Cape Romano. 

 Both outbreaks caused heavy fishmor- 

 talities. 



During the 1957 outbreak of red tide, 

 experimental application of copper sul- 

 phate as a possible control measure 

 was used in the coastal areas from 

 Anclote Key to Cape Romano by the 

 U. S. Bureau of Commercial Fisheries 

 in cooperation with the Florida State 

 Board of Conservation. Copper sulphate 

 was distributed from planes, boats, and 

 bridges in these areas. The results of 

 the large-scale test in the St. Peters- 

 burg area were reported by Rounsefell 

 and Evans (1958). As a result the 

 copper concentrations recorded during 

 this experimental application may not 

 necessarily represent the natural 

 levels of this element. 



METHODS 



Sampling techniques 



The collections of water samples for 

 determination of salinity, copper, total 

 and inorganic phosphate -phosphorus, 

 nitrate -nitrite nitrogen, and abundance 

 of G. breve were made as described by 

 Finucane and Dragovich (1959), except 

 as indicated below. 



For the data presented in Part I, the 

 surface water samples were collected 

 with a polyethylene bucket and sub- 

 surface samples with a weighted poly- 

 ethylene container. In Part II, all water 

 samples, except at river stations, for 

 salinity, nitrate -nitrite nitrogen, and 

 total and inorganic phosphate - 

 phosphorus were collected with re- 

 versing Nansen water bottles. To 

 eliminate metallic contamination, the 

 water samples for G. breve counts and 

 copper analyses continued to be col- 

 lected in polyethylene containers, which 

 were replaced during this investigation 

 by modified Van Dorn sampling bottles 

 (VanDorn, 1957). Weighted polyethylene 

 containers were used to secure all 

 samples from the river stations. Water 

 samples were collected from four 

 evenly spaced depths, including surface 

 and bottom. At river stations they were 

 collected from surface and bottom only. 



At all stations represented in Part I 

 and at the river stations in Part II, 

 water temperatures were measured 

 with a mercury thermometer to the 

 nearest 10th of a degree centigrade. 

 In Tampa Bay and neritic stations in 

 Part II, the water temperatures were 

 recorded with a thermistor (Whitney 

 underwater thermometer, model T65) 

 to the nearest 10th of a degree centi- 

 grade. 



Enumeration of Gymnodinium breve 



Water samples for G. breve counts 

 were usually examined within 24 hours 

 after collection. All of the samples 

 were concentrated (the organisms given 

 time to move to the surface of the sam- 

 ple) under 40-watt fluorescent lights. 

 Satisfactory concentration of the organ- 

 ism was obtained with lights 14 inches 

 above the flasks. The period of concen- 

 tration at room temperature was 

 usually 16-18 hours and never less than 

 4 hours. 



Sample aliquots were examined for 

 living organisms with a stereoscopic, 

 inclined binocular microscope equipped 

 with 18X wide-field eyepieces. For 

 general detection and for counting of 

 both concentrated and mixed samples, 

 magnifications of 54X and 144X were 



