THE IMPORTANCE OF BENTHIC FAUNA IN THE DIET OF SMALL COMMON BREAM ABRAMIS BRAMA (L.), ROACH RUTILUS RUTILUS (L.), PIKEPERCH SANDER LUCIOPERCA (L.) AND RUFFE GYMNOCEPHALUS CERNUUS (L.) IN THE WŁOCŁAWEK RESERVOIR
Nicholas Copernicus University, Institute of Ecology and Environmental Protection, Department of Hydrobiology, Toruń, Poland
ABSTRACT. The food composition of small common bream, roach, pikeperch and ruffe was studied in the shore area of the Włocławek Reservoir between July and October 1999. Zoobenthos and pelagic Chironomidae pupae dominated. Rotifers, copepods and cladoceran pelagic zooplankton were almost not consumed at all. Common bream fed mainly on benthic cladoceran Chydoridae and Chironomidae larvae. Roach consumed vegetation, Chironomidae larvae and small molluscs Sphaeriidae. Ruffe ate Chironomidae larvae, and pikeperch ate fish and various developmental stages of Chironomidae. Pelophilous chironomid forms, mainly from the genus Chironomus, dominated among the consumed larvae. Due to its exceptional abundance, the benthic fauna in the Włocławek Reservoir is an attractive food source for fish, and it plays an important role in their diet from the earliest life stages onwards. The benthic fauna also provides good developmental conditions, especially for typical benthic feeders.
Key words: COMMON BREAM (ABRAMIS BRAMA), RUFFE (GYMNOCEPHALUS CERNUUS), ROACH (RUTILUS RUTILUS), PIKEPERCH (SANDER LUCIOPERCA), DIET, BENTHIC FAUNA, DAM RESERVOIR
Tomasz Kakareko, Uniwersytet Mikołaja Kopernika, Instytut Ekologii i Ochrony Środowiska, Zakład Hydrobiologii, ul. Gagarina 9, 87-100 Toruń; Tel./Fax: +48 56 6114450, +48 56 614443;