Age and growth of European eels (Anguilla anguilla) in the Elbe River system in Germany

Abstract

Models to describe the stock dynamics of the endangered European eel, Anguilla anguilla, are needed on river system level to develop conservation management strategies. For these models, estimations of age and growth of local eel stocks are important prerequisites. To investigate the variation of these two parameters I collected 160 European silver eels grouped by 100mm size classes at capture from the lower part of the Elbe River in Germany during fall 2011. Length of collected eels ranged from 360mm to 957mm and age from 7 years to 23 years. Mean age and growth, estimated by otolith increments, were higher for females (14 years, growth 52mmyear−1) than for males (13 years, 35mmyear−1). Larger females were older and grew faster as compared to smaller females. Across all size classes at capture, the weighted mean age and annual length increment based on the percentage of eels per size class of the migrating silver eels were 13 years and 50mmyear−1, respectively. The parameters of the von Bertalanffy growth model L∞, k and t0 for silver eels are given, which can be used to model the dynamics of the eel stock of the Elbe River system.