Sudekum et al.: Life history and ecology of Caranx ignobilis and Caranx melampygus 



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and unidentified) were found in 14.8% of the guts, 

 cephalopods in 24.7%, and crustaceans (including lob- 

 sters, crabs, and shrimp) in 17.3%. 



Of 147 guts of C. melampygus examined, 85.0% con- 

 tained identifiable prey items (Table 4), and 96.0% of 

 these contained the remains of fish. The wrasses 

 (Labridae), goatfish (Mullidae), filefish (Monacanthi- 

 dae), damselfish (Pomacentridae), parrotfish (Scaridae), 

 and bigeyes (Priacanthidae) were the most important 

 families of fishes in the diet of C. melampygus. Eels 

 and cephalopods made negligible contributions. Crusta- 

 ceans of many diverse groups were found in 19.2% of 

 the guts with identifiable prey items, but they ac- 

 counted for less than 1% of total prey volume. Palinurid 

 lobsters were absent. 



Comparison of the diets of the two length categories 

 of C. melampygus showed only one significant dif- 

 ference. Crustaceans were found in 17 of 42 guts from 

 fish of the smaller length category (<350mm SL), but 

 in only 7 of 107 guts from the larger length category 

 (>350mm SL). This indicates a statistically signifi- 

 cant Or 21.5, df 1, P<0.001) change in the diet of 

 C. melampygus with size. 



The Pianka (1973) index of overlap, used to measure 

 the degree of similarity in the diets of the two 

 carangids, was calculated from the proportional IRI 

 representation (% of summed IRI) for each prey group 

 found in the two species. The value of A yz was 0.42. 



Maximum feeding rates were determined for six cap- 

 tive juvenile C. melampygus. These fish started at a 

 mean weight of 124.5 g, and during the course of the 



