Piscivory and Trophic Position of Anguilla anguilla in Two Lakes: Importance of Macrozoobenthos Density

• Published in: Journal of Fish Biology
• Main Authors: DOERNER Hendrik, SKOV Christian, BERG Soeren, SCHULZE Torsten, BEARE Douglas, VAN DER VELDE Gerard
• Language: English
• Published: BLACKWELL PUBLISHING 2009
• Subjects: Anguilla anguilla
• Online Access: https://publications.jrc.ec.europa.eu/repository/handle/JRC34655; https://doi.org/10.1111/j.1095-8649.2009.02289.x

The feeding habits of large eels Anguilla anguilla (> 30 cm LT) were compared in two lakes of different environmental state: Lake Großer Vätersee (LGV), Germany (clear water, mesotrophic, submerged macrophytes) and Lake Vallum (LV), Denmark (turbid, eutrophic, no submerged macrophytes). The availability of macrozoobenthos was higher in LV (3,500 ind. m-2) than in LGV (1,500 ind. m-2). The abundance of small prey fish (40-99 mm LT) was highest in LV. In LV, eels fed on macroinvertebrates, in particular chironomid larvae. In LGV, eels used fish as the main food component. Stable isotope analyses confirmed the dietary results. The estimated mean trophic positions of eels in LGV (3.74 ± 0.2) was one level higher than those of eels in LV (2.71 ± 0.2). Based on these results, piscivory among eels is generally controlled by the availability of insect larvae. Stable isotope analysis further indicated that eels may act as integrators between benthic and pelagic food webs when availability of insect larvae is low. JRC.G.4 - Maritime affairs