Young fish in gravel pit lakes: Habitat choice and impact of supplemented dead wood on abundance

Studie

In this study, the habitat choice of young fish (0+ and 1+) and the impact of three different treatments (treatments were: supplemented deadwood, shallow water zones and stocking), measured against unmanaged control treatments, on the abundance of young fish in gravel pit lakes was analysed. In total, 20 gravel pit lakes were involved in this study. Sampling took place before and after treatment implication and a BACI design for analysis was applied. Habitat choice and BACI design were investigated by comparing number per unit effort (NPUE) in different habitat types and in different treatment groups. Young fish in general showed a strong association with structured habitats such as submerged macrophytes, while some species, in particular perch and roach, were also found in open habitats more often than in reed habitats. This behaviour is discussed. Furthermore, no effect of the treatments stocking and supplemented deadwood was found on young fish in general, while roach was positively impacted by supplemented deadwood and rudd negatively by stocking. The creation of shallow water zones had almost significant positive effects on the abundance of young fish in gravel pit lakes and positive significant effects on rudd. Therefore, it is suggested that shallow water zones in gravel pit lakes pose a bottleneck in the abundance of young fish and managers of gravel pit lakes should consider in investing in the creation of such shallow water zones.

Feldhege, F. 2022. Young fish in gravel pit lakes: Habitat choice and impact of supplemented dead wood on abundance. Studienprojekt, Humboldt-Universität zu Berlin, Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB) Berlin.


Veröffentlicht : 2022
Erschienen in : Studienprojekt, Humboldt-Universität zu Berlin, Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB) Berlin