money and effort were expended in merely monitoring by fast boat and air- 

 plane the areas where outbreaks might occur. Despite the handicap of at- 

 tempting to carry on research while parrying the innpatient attacks of an 

 indignant public demanding action -- any kind of action -- considerable knowl- 

 edge was accumulated. 



The causative organism, a naked dinoflagellate (Gymnodinium 

 breve Davis), was successfully reared in both unialgal and pure cultures. 

 Much has been learned of the effects of various physical and chemical factors 

 on its survival and growth, and of the concentrations of the organism re- 

 quired to exude sufficient toxin to render sea water toxic to other organisms. 



Several years of field collection of this red-tide organism with con- 

 current measurements of salinity, temperature, and chemical composition of 

 the water have failed to show any limiting relation between abundance of the 

 organism and levels of phosphorus, nitrates, nitrites, copper, etc. The or- 

 ganism does not thrive in water of low salinity. Outbreaks appear to coincide 

 with periods of heavy land drainage when wind velocities are low, especially 

 if the light winds are blowing toward the shore. It would thus appear that the 

 overblooms occur when and where nutrient -laden fresh water mixes with the 

 salt waters of the Gulf. 



During the field operations, numerous hydrographic data were gath- 

 ered that are of great value to other fishery investigations. Certain of these 

 observations will be continued, but field work on red tide as such has been 

 terminated. This does not mean that broader knowledge being gained in our 

 other estuarine work will not eventually contribute to a greater knowledge of 

 the causes of these sporadic outbreaks. 



One phase of red-tide work is being continued. It is the search for 

 a chemical agent that will control the red-tide organism without harming other 

 valuable organisnns. A report on current progress appears elsewhere in this 

 report. 



St. Petersburg Beach Field Station Upon termination of red-tide field ac- 



tivities, it was necessary to decide on the future role of this field station. 

 Since the station has excellent hydrographic observations since 1957 for Tampa 

 Bay and the adjacent waters of the Gulf, it was decided that Tampa Bay would 

 be a suitable area for conducting needed research on the estuaries of the east- 

 ern Gulf. The field station is now operating independently of the laboratory 

 at Galveston. 



Research Vessel Several naval architects formally expressed their opinion 



that the funds available for construction of the proposed laboratory research 

 vessel are insufficient to construct and equip the type of vessel needed. Ne- 

 gotiations for an architect are, therefore, being held in abeyance unless or 

 until adequate funds become available. 



