FISHERY BULLETIN: VOL. 70, NO. 4 



obtained from cleaning ranges from 27 to 67% 

 with maximum percentages obtained in 26 to 40 

 mm fish (58 to 67 9^). 



Most of the fish skin, flesh, and scales present 

 in the stomachs are construed to have come from 

 cleaning activities, since other than occasional 

 fish larvae, fish per se were seldom encountered 

 in any of the stomachs examined. 



A sizable portion of the diet of juveniles of 

 all size classes consists of free-living organisms, 

 primarily copepods, mysids, and small shrimp 

 (see Figure 1). Free-living organisms account 

 for 96 to 100 9f of the stomach contents of ju- 

 veniles outside the 26 to 60 mm size classes. 

 Free-living copepods comprise the major food 

 item of 21 to 25 mm individuals whereas mysids 

 and small shrimp made up the major food items 

 of fish in the 61 to 100 mm size classes. 



Since there were no prior reports on 0. saurus 

 functioning as a cleaner, additional analyses 

 were made of other specimens collected from 

 other sites at other times. Collections of ju- 

 venile 0. saurus were obtained from Dr. Carter 

 R. Gilbert of the Florida State Museum for this 

 purpose. The results of analyses of these col- 

 lections are given in Table 1. Ectoparasites 

 were present in the stomachs of fish belonging 

 to all size classes examined. The relative con- 

 tribution of ectoparasites to the diet was again 

 maximum in fish between 26 and 40 mm in 

 length. A maximum of 24 ectoparasites was re- 

 covered from each of two stomachs of fish 41 

 to 60 mm long. The relative contribution of 

 ectoparasites to the total diet decreased dramat- 

 ically in fish greater than 60 mm in length. The 

 data from analyses of museum collections cor- 



related remarkably well with the data presented 

 earlier on freshly collected specimens. The low- 

 er percentages of stomach contents attributable 

 to ectoparasites in the museum collections may 

 have been due to the fact that these fish had 

 been stored for 10 to 20 years and were not as 

 well preserved as our freshly collected specimens. 

 This was suggested by the presence of significant 

 amounts of unidentifiable debris in the stomachs 

 of the museum fish. 



DIPLODUS HOLBROOKI 



Figure 2 shows the results of analyses of 

 stomach contents of juvenile D. holbrooki in the 

 10 .size classes obtained in our collections. As 

 was the case with 0. saurus, D. holbrooki goes 

 through a juvenile stage in which it is a cleaner. 

 One or more species of the ectoparasitic branch- 

 iuran, Argulus, is significant in the diet of ju- 

 veniles between 21 and 50 mm in length. The 

 percentage of ectoparasites in the total stomach 

 contents is maximum in fish 31 to 35 mm long 

 (20%) with somewhat smaller percentages re- 

 corded in fish 26 to 30 mm long and in fish 36 

 to 40 mm long. A maximum of 16 ectoparasites 

 (Argulu^) was recovered from the stomach of 

 a single fish in the 36 to 40 mm size class. The. 

 relative contribution of ectoparasites to the tot^J 

 stomach contents decreases dramatically to less 

 than 1% in fish less than 61 mm long. Only one 

 ectoparasite was found in the stomachs of 35 

 fish 61 to 70 mm long. Ectoparasites were ab- 

 sent from the stomachs of fish less than 21 mm 

 or greater than 70 mm in length. Likewise, ecto- 

 parasites were absent from the stomachs of 18 



Table 1. — Analyses of stomach contents of Oligoplites saurus obtained from Florida 



State Museum.' 



Size 

 class (mm) 



Number 

 of 

 fish 



Number of 

 stomadis 



Stomachs with food 

 and ectoparasites 



Number of ectoparasites 

 per stomach with food 



Ectoparasites 

 % of total 



Fish token from collections indicated as follows: 



Cedar Key, Fla., 10/27/47, 7/24/48, 10/24/46, 9/25/33. 

 Little Gasparilla Pass, Charlotte Co., Fla., 7/21/60. 



1114 



