Food resource utilization by juvenile Baltic cod Gadus morhua: a mechanism potentially influencing recruitment success at the demersal juvenile stage?

摘要: Pelagic and demersal juvenile Baltic cod Gadus morhua L. were collected during surveys in the Bornholm Basin (Baltic Sea) autumn 1994. Stomach contents examined for prey compo- sition order to evaluate potential importance of pelagic habitats recruitment success. Juvenile less than 40 mm fed exclusively on such as copepods cladocer- ans. Between 50 juveniles began consume benthic mysids amphipods; however, still dominant food organisms. 70 items consumed amphipods, with comprising a minor com- ponent diet. 160 juveniles' diet was composed an increase diversity. Mysids slightly important diet, while abun- dance polychaetes, decapods fish increased size. Amphipods remained almost constant above 60 length. These results indicate that major change resource utilization started occur at length mm, main taking place approximately suggesting make transition habitat this This preference is also reflected size num- bers consumed. much smaller their con- specifics. Neither nor numbers by small from study differed reported be taken corresponding Atlantic North Sea. However, organisms larger 90 smaller, higher, those other areas. The apparent overlap among different groups observed suggests years low abundance, or high abundance juveniles, strong intra-specific competition resources may affect success cod.