Table 2.- 



-Salinity, temperature, and incidence of G. 



(1954-57) ~ 



breve in Florida waters 



presence of the organism in those areas in- 

 dicates that it can exist in an oceanic environ- 

 ment. 



G. breve concentrations varied throughout 

 the investigation and exhibited patchy distribu- 

 tion. This "patchiness" was particularly no- 

 ticeable during the outbreaks of red tide. 

 Counts varied from to 600,000/1. at stations 

 fronn Egmont Channel to Venice Inlet in a 

 period of less than 3 hours during Oct. 23, 

 1957 (table 3), Uneven distribution of dino- 

 flagellates also has been observed in the North 

 Sea (Lucas, 1942). 



The majority of 1955 and 1956 samples 

 contained less than 1000/1., which may be 

 considered a resident population level (fig. 6). 

 G. breve counts usually were higher in neritic 

 than in estuarine waters during these years. 

 In 1956, this organism was observed only in 



the neritic waters from Naples to the Florida 

 Everglades. The highest nunnbers were re- 

 corded during blooms in 1954 and 1957. Counts 

 of 7,500,000 and 100,000,000/1. were observed 

 in two areas of dying fish during Decennber 

 of 1954 and 1957. Lasker and Smith (1954) 

 reported 15,000,000/1. as the highest number 

 observed during the 1946-47 red-tide outbreak. 

 Lackey and Hynes (1955) reported 4,814,000/1 . 

 in 1954. 



The densest concentrations and greatest 

 numbers of the organism usually occurred 

 during fall and winter (September-January) 

 and often were preceded by a period of ex- 

 cessive rainfall (fig. 6 and table 4). During 

 the red-tide year 1954, precipitation was I 2.95 

 inches above normal in area C and 8.68 inches 

 above normal in area D (table 4). In 1955 and 

 1956, which were not red-tide years, rainfall 



