Simulated migration enhances sexual maturation of farmed European eels

摘要

Sexual maturation of European eels (Anguilla anguilld) occurs during and/or after the approximately 6,000km migration from their freshwater habitats in Europe across the Atlantic to spawning grounds in the Sargasso Sea.At the Aquaculture Europe Conference held last fall in Rotterdam, the Netherlands, Arjan Palstra from the Institute for Marine Resources and Ecosystem Studies (IMARES) of Wageningen University described what is likely the first study to simulate a mixed-sex, group-wise freshwater migration under mimicked photothermal conditions. Palstrca and collegues Daan Mes and Ron Dirks used farmed silver eels to determine the effects of this simulated 'migration on the progression of sexual maturationSilver eels swam in a flume against a flow of 0.57 m/sec (optimal swimming speed for males) under an 8:16 hour light:dark regime in freshwater at 11.5°C,covering an estimated 689km in two weeks, then in complete darkness in seawater at daily fluctuating temperatures between 11.7°C and 10.TC mimicking migrations in the Atlantic for nine weeks, covering an estimated 3,103km. The total 'distance' the eelsare estimated to have swum in the flume was 3792km.