Age, growth and condition of European eel (Anguilla anguilla) from six lakes in the river Havel system (Germany)

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A total of 146 female yellow European eels (Anguilla anguilla) of length 23.0 to 64.5 cm and ages 3 to 13 years were collected by electro fishing from six lakes in the river Havel system (Germany) in spring 2001. Growth rates estimated by means of otoliths increments, and condition of eels, varied between individuals within one lake and between lakes. Highest growth rates were recorded from Lake Blankensee with a mean growth of 5.2 cm per year, and lowest growth rates were recorded from Lake Eiserbude and Lake Sacrow with a mean growth of 4.0 cm per year. In all lakes together, the overall mean annual increment was estimated at 4.5 cm per year. The highest annual increment on the otoliths generally occurred in all lakes in the first and second year of growth in freshwater with 6.4 to 7.7 cm per year. In the following ten years the annual increment then remained almost constant or decreased slightly with 1.4 - 5.6 cm per year.