Associated phytoplankton Diatoms increased in incidence and numbers dur- 



ing the summer and fall of I960. The following genera and species were found 

 in great numbers in these areas: Ceratium furca, Ceratium fusus, Proro- 

 centrum micans, Gymnodinium spp. , Peridinium sp. , Skeletonema costatum, 

 Biddulphia sinensis, Asterionella japonica, Grammatophora sp. , and Melosira 

 sp. The blooms of P. micans and C. furca may represent a normal seasonal 

 pattern since they occurred during November of both 1959 and I960. An un- 

 known chain-forming species of Gymnodinium was noted for the first time dur- 

 ing September I960 in Tampa Bay in numbers as high as 1, 650, 000 per liter. 

 G. breve was one of the dominant dinoflagellates from August through October 

 I960 in the offshore waters. 



Dinoflagellates and diatoms diminished during the w^inter and spring 

 of 1961. Diatoms were virtually absent in the neritic waters from 20-40 miles 

 offshore, the greatest numbers occurring in Tampa Bay and the nearshore 

 waters. In contrast to the distribution and abundance of G. breve , the most 

 productive areas for other dinoflagellates were the estuarine waters of central 

 and upper Tampa Bay. No apparent association of G. breve blooms with other 

 phytoplankton was noted. 



64 



