Critical swimming speed of yellow- and silver-phase European eel (Anguilla anguilla, L.).

The prime objective of this study was to evaluate differences between the swimming performance of two distinct life stages of European eels. The critical swimming speed (Ucrit) of 29 yellow- and 33 silver-phase eels was evaluated in a swim tunnel. Silver-phase eels showed a better swimming performance (Ucrit = 0.66 ms/1) than yellow individuals (Ucrit = 0.43 ms/1). Male and female silver eels reached an identical Ucrit despite their different sizes, which may be a strategy to increase the synchronization of arrival at the spawning grounds