Eels at the Edge: Science, Status, and Conservation Concerns

Does Stocking of Danish Lowland Streams with Elvers Increase European Eel Populations?

Michael I. Pedersen


Abstract.—To counteract low elver recruitment to the Danish coast, a stocking program has been under development since the late 1980s. Glass eels imported from southern Europe are cultured to 2–5 g and stocked throughout the country in fresh and brackish water. To assess the value of these stockings, selected streams were stocked with eels weighing 3 and 9 g. Poststock evaluations by electrofishing were done 3–63 d after stocking in one system and up to four years later in another system. Instantaneous daily disappearance rate, including emigration and natural mortality, was high (D = 0.006–0.153) in both river systems. The reasons may include low water temperatures combined with a habitat offering too little shelter for the stocked eels.