Most of the isopods were free-swimming 

 cymothoids and were grouped in the genus 

 Aegathoa. 



Penaeids were represented by small numbers 

 of larvae of Sicyonia spp., Traclujpeneus spp., 

 and Penaeus duoraruvx; Sicyonia (mainly 

 mysis I and mysis III stages) constituted 36 

 percent of this family. They were restricted to 

 the offshore area and lower areas of Tampa 

 Bay (stations 1-4) . Only two samples con- 

 tained Trachypeneus larvae. The pink shrimp, 

 P. dnorarum, contributed 16 percent of the 

 total penaeids. Postlarvae III stages of P. duo- 

 rarum appeared most frequently; only occas- 

 ional postlarvae I and II and mysis III were 

 taken. These larvae were most abundant in the 

 summer and were collected primarily in Boca 

 Ciega Bay (station 6) and the immediately 

 adjacent Gulf waters. Our observation of the 

 temporal occurrence of larval stages of pink 

 shrimp in Tampa Bay agrees generally with 

 the findings of Eldred et al. (1965). 



Appendicularia spp. and Oikopleura spp. 

 were common appendiculariids and were found 

 at most of the sampling locations. 



A number of eggs and larval fish were col- 

 lected. Many of the fishes were identified as 

 commercially important species. The role of 

 Tampa Bay in the production of species im- 

 portant in Gulf fisheries was discussed by 

 Sykes and Finucane (1965). 



Fish eggs were taken most frequently 18.5 

 km. offshore, but were most abundant at Eg- 

 mont Key where 54 percent of the total number 

 were collected. They were not identified. 



Larval fish accounted for 0.8 percent of the 

 total number of zooplankters. All engraulids 

 were identified as Anchoa spp. Identified 

 sciaenids were Cynoscion spp. and Leiostomus 

 xanthurus. Larvae of L. xanthtirus, 6 to 15 

 mm. long, were taken from late fall through 

 early spring in Boca Ciega Bay and 6.5 km. 

 offshore. Cynoscion spp. appeared infrequently 

 during the spring and summer at most of the 

 bay stations but were not found in Hills- 

 borough Bay or offshore. Seventy-seven per- 

 cent of the clupeids (3 to 20 mm. long) were 

 identified as Brcvoortia. All syngnathid larvae 

 (5 to 44 mm. long) were of the genus Syngna- 

 thus. 



Chaetognaths made up 3 percent of the total 

 number of zooplankters. All undamaged speci- 

 mens more than 5 mm. long were identified as 

 Sagitta. S. hispida was the only chaetognath 

 found throughout the area of investigation. It 

 was plentiful in all seasons and was the second 

 most abundant taxon during the winter (fig. 

 4). The broad dispersal and numerical abun- 

 dance of immature Sagitta less than 5 mm. 

 long suggest that Sagitta breed both in Tampa 

 Bay and the adjacent offshore waters. The 

 smallest chaetognath was 2.5 mm. long, but it 

 is likely that smaller ones escaped through the 

 net. 



Polychaete larvae made up 2.4 percent of the 

 total number of zooplankters. Terebellids (0.4 

 to 4 mm. long) were numerous in samples that 

 contained a high proportion of Bellerochea 

 malleus. The gut always contained large quan- 

 tities of chlorophyll. None was identified to 

 genus. Spionids (0.4 to 4 mm. long) were col- 

 lected at 11 to the 14 sampling locations, but 

 the genera Polydora and Prionospio were col- 

 lected only off Egmont Key, in Boca Ciega Bay 

 (station 6), and in Terra Ceia Bay. 



FORMS RARELY CAUGHT 



This group of organisms consisted of taxa 

 which were in less than 10 percent of the 

 samples (table 7). Only 10 of these taxa ac- 

 counted for 0.1 percent or more of the total 

 number of zooplankters, though many of them 

 (e.g. pagurids, mollusks, and echinoderms) are 

 common as adults of this area. The paucity of 

 planktonic stages in this study may be ascribed 

 partially to the large mesh of the collecting net 

 and to the fact that only surface samples were 

 taken. 



The areal distribution of most of the plank- 

 ters in this group was limited. Most of the 

 cladocerans (66 percent), cirripedians (61 

 percent), and lancelets (60 percent) were col- 

 lected in one sample taken during May from 

 lower Hillsborough Bay. Fifty-three percent of 

 the pagurids were taken in August in a single 

 sample from upper Tampa Bay. Forty-two per- 

 cent of the larval blennies were collected from 

 the .same area ; they were present throughout 

 the year but were most abundant in September. 

 Sagitta helenae and S. enflata occurred fre- 



218 



U.S. FISH AND WILIFE SERVICE 



