Diel feeding periodicity and daily ration of shelf break fish species

Abstract

The evaluation of the daily ration and feeding periodicity in a Mediterranean demersal fish assemblage under natural conditions is presented. Data were obtained during four trawl surveys conducted on the shelf-edge of the central Mediterranean Sea. Recently, researchers have begun to consider this area an essential fish habitat due to its extremely high productivity and diversity. The species which typified the assemblage were the fish Macroramphosus scolopax, Lepidotrigla cavillone, Mullus barbatus, Serranus hepatus, Argentina sphyraena and Glossanodon leioglossus. Fish were collected at three hour intervals throughout four 24 h sampling periods representing annual seasons. The study was based on the analysis of catch data and stomach fullness per setting time. Results show significant variation of feeding periodicity among species within daytime. The amount of food consumed daily, calculated according to the Elliott & Persson model, is compared to the patterns reported in literature for Atlantic fish species with similar trophic habits. Higher values of daily consumption could be related to the reproductive period for most of the above mentioned species.