is known about the physiology of this organism. 

 Skujaella ( Trichodesmium ) erythraeum is re- 

 ported to grow 20 m. below the surface in the 

 Red Sea and dead cells accumulate on the 

 surface. 



Concentrations of G. breve varied from to 

 53,800 cells per liter during the period. Maxi- 

 mum concentrations and widest distribution 

 were in September and February, during 

 periods of reduced salinity. Low incidence and 

 concentrations in the period March to August 

 coincided with extremely high salinities. Be- 

 cause of little rainfall, salinities increased 

 progressively from February to August. During 

 May, 95 percent of all offshore salinities were 

 above 35.50%„. Fifteen to 20 nniles offshore, all 

 salinities were above 36.00%„. G. breve was 

 present at all depths, but was most abundant 

 at the surface. 



A preliminary examination was made of 

 preserved plankton collections taken in Janu- 

 ary, February, and March 1963 (Collection 

 and examination of living plankton began in 

 April). The principal phytoplankton components 

 before, during, and after the April red-tide 

 outbreak in Tampa Bay were diatoms, dino- 

 flagellates (including G. breve ), and Tintin- 

 nidae. Cyanophytes and silicoflagellates were 

 of minor importance. Phytoplankton was much 

 denser in the upper portions of Tampa Bay 

 than in the lower part of the estuary. A pre- 

 liminary analysis of phytoplankton counts and 

 associated hydrologic data indicated that 

 blooms of G^. breve during April were coin- 

 cidental with (1) blooms of Ceratium furca , 

 Prorocentrum micans , Gonyaulax diegensis , 

 Rhizosolenia stolterfothii , and Tintinnidae; 

 and (2) the intrusion of offshore waters into 

 Tampa Bay during a period of exceptionally 

 low rainfall. The offshore waters contained 

 G. breve . The change in planktonic successions 

 cannot be accounted for by any of the observed 

 hydrological factors alone. The reduction in 

 plankton populations prior to the blooms is 

 evidence, however, thsrt the phytoplankton was 

 kept at low levels by physiological linnitations 

 and physical dispersal. 



study, and finally, by a combination of these, 

 the development of control techniques. 



Much more detailed and thorough research 

 on G. breve itself is an outstanding need. It is 

 a highly sensitive organism that is difficult to 

 work with- -if it were not so sensitive, we would 

 have red tides with us constantly. Comprehen- 

 sive and detailed work on the fundamental 

 cytology of this organism will be required 

 before we are able to isolate the critical fac- 

 tors in the environment. 



THE PUBLIC HEALTH SIGNIFICANCE OF 

 GYMNODINIUM BREVE 



By Sammy M. Ray 



Marine Laboratory, Agricultural and 

 Mechanical College, Texas, Galveston, Tex. 



By way of investigating the public health 

 significance of G. breve , mussels and oysters 

 that had been held in cultures of this organism 

 were fed to chicks to determine whether toxic 

 symptoms would be produced. Preliminary re- 

 sults indicate a relation between the number of 

 G. breve cells ingested by the mollusks and 

 the severity of the symptonns in chicks to 

 which the mollusks had been fed. Symptoms 

 ranged from partial loss of equilibrium to 

 death. Similar tests are planned with cats as 

 the experimental animals. 



Of interest is the fact that the annelid 

 Polydora quickly emerged from oysters sub- 

 jected to cultures of G. breve . Research will 

 continue on the toxic effects to polychaetes. 



The possibility appears to be good that 

 G. breve is of significance in shellfish poison- 

 ing. Only a few authenticated cases of such 

 poisoning have been reported in the GuK of 

 Mexico, probably in part because mollusks 

 normally are not produced commercially in 

 areas where red tides occur. 



Work will continue also in culturing, and in 

 comparing the toxicity of Gonyaulax catenella 

 with G. monilata and G, breve. 



AN APPROACH TO THE RED-TIDE 

 PROBLEM 



By Albert W. Collier 



Oceanographic Institute of Florida State 

 University, Tallahass'fee, Fla. 



Red-tide research can be approached in 

 three steps: (1) explaining how outbreaks are 

 caused and why they occur when they do; 

 (2) deriving from this approach a method for 

 predicting outbreaks; (3) with the knowledge 

 gained from explanation and prediction, 

 attempting to develop control measures. These 

 steps require experimentation, intensive field 



COMMENTS ON ETIOLOGY OF RED TIDE 



By Gordon Gunter 



Gulf Coast Research Laboratory 

 Ocean Springs, Miss. 



In spite of the meticulous manner in which 

 scientists collect samples, our methods still 

 appear to be somewhat crude. This shortcom- 

 ing may not be critical, however, in the study 

 of red tide. Except in years of extremely 

 heavy blooms, few people concern themselves 

 with this phenomenon because no damage is 

 done. Observations of the past agree with 

 recent statistical analyses in showing that 



