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Fishery Bulletin 97(3), 1999 



Figure 5 



Monthly variations of the percentage contribution by number (A) and by weight (B) of the major 

 prey groups and species in Pagrus pagriis diet. 



ferent prey sizes. There is evidence that prey size 

 differences reflect changing food preference with fish 

 size, as well as the ability of larger individuals to 

 capture larger animals. Mean prey-size increases 

 with increasing predator size so that the energy re- 

 turn per unit of effort is optimal. The relatively high 

 percentage of empty stomachs found in the size 

 class and the positive allometry on full stomachs 

 suggest that feeding intensity increased with fish 

 size. These results are not consistent with the gen- 

 eral tendency of a decreased rate of metabolism typi- 

 cal of larger fish found in many studies (e.g. Smith 

 and Page, 1969; Martin, 1970; Kislialioglu and 

 Gibson, 1976; Fange and Grove, 1979; Werner, 1979; 

 Grove and Crawford, 1980; Robb and Hislop, 19801, 

 presumably because the specimens examined were 



immature. Hence it may be concluded that feeding 

 rates exhibited by juveniles were high in terms of 

 both feeding intensity and the amount of food con- 

 sumed. Because red porgy on the Cretan shelf does 

 not become mature until the third year of life, it re- 

 mains for a long period in highly productive shallow 

 waters and thus directs its effort entirely into so- 

 matic growth. The resultant increase in body size 

 would thereby lead to an increase in the fecundity of 

 individuals when they do, finally, become mature 

 (Stearns, 1992). 



Papaconstantinou and Caragitsou ( 1989) reported 

 that in specimens >200 mm FL the importance of 

 decapods, fish, and polychaetes declined rapidly with 

 size, being replaced by anthozoans, brachyurans, and 

 echinoderms. Unlike the results of the present study, 



