ROSS: TROPHIC ONTOGENY OK LEOPARD SEAROBIN 



Table l. — Food items utilized by Prionotus scitulus collected between April 1972 and May 1973 at three stations in Tampa Bay, Fla. 



Based on 469 specimens containing food items. 



'Only a trace amount of food present, 



^An accurate count of individuals was not possible. 



13 mo examined, dropping between 30 and 40^^ in 

 September, January, and May. Number, volume, 

 and percent occurrence for B. floridae all showed 

 major peaks in utilization between June and Au- 

 gust, and October and December 1972. 

 Polychaetes were irregular in percent occurrence, 

 but the data suggest a peak in spring and summer, 

 while natantians and brachyurans showed in- 

 creases in percent occurrence in the spring and 

 fall. Amphipods, cumaceans, mysids, and 

 pelecypods showed strong spring peaks in impor- 

 tance. 



Nine size groups of P. scitulus (21-40, 41-60, 

 61-80, 81-90, 91-100, 101-110, 111-120, 121-130, 

 13 1-140) reached stabilized horizontal asymptotes 

 of cumulative trophic diversity versus cumulative 

 stomachs examined. The analyses of size changes 

 in feeding are based on these groups. 



The percent occurrence of lancelets and 

 polychaetes increased with increasing fish size, 

 while gammarid amphipods decreased (Table 2). 

 Brachyurans, cumaceans, copepods, larval crusta- 

 ceans, pelecypods, and ostracods increased in per- 

 cent occurrence for searobins up to 80-100 mm. 



Table 2. — Percentage of prey occurrence for size groups (millimeters standard length) of Prionotus 

 scitulus from Tampa Bay, Fla., 1972-73. Only prey categories with an overall occurrence of 1% or 

 greater were included. 



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