Food, growth and production of Anguilla anguilla in a small Danish stream

A total of 837 eels from the Køge-Lellinge å were examined with regard to food items and to the relationship between feeding intensity and prevailing water temperature. The invertebrate groups Isopoda, Hirudinea, Gastropoda and insect larvae were the dominating food items. Feeding intensity was correlated with water temperature and eventually stopped at temperatures below about 5°C.

A total of 177 yellow eels were age-determined by burning of the otoliths A von Bertalanffy growth curve fitted the data well, with L∞ = 59·83 cm, K = 0·5683. By means of weight per age and catch per age data a total production of 9·3 g wet weight per m2 per year and a P/B reationship of 0·57 were calculated.

The calculation of production is somewhat uncertain on account of dubious mortality data, and in the future greater efford should be devoted to eel production in freshwater streams, which are significant as gowth areas for commercial eel fishery.