Overwintering dormancy behaviour of the European eel (Anguilla anguilla L.) in a large lake
2015 (English)In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 24, no 4, 532-543 p.Article in journal (Refereed) Published
Overwintering dormancy behaviour was studied in female silver eels in Lake Mälaren in Sweden between 2008 and 2010. Depth choices and movements in relation to temperature were analysed from pressure andtemperature records for 13 eels with implanted data storage tags, covering 17 overwintering periods and threeintervening summer periods. Dormancy commenced in October–November as temperatures fell below 4–12 °C.Eels tended to remain motionless throughout the winter, with some short periods of activity signalled by smallchanges in depth distributions. During dormancy, the eel shows a clear avoidance of shallow areas <5 m in favourof the 10–25-m-depth interval. Activity tended to resume 4–6 months later in April–May as temperatures roseabove 3–7 °C and ice cover broke, and eels spent more time at shallower depths of <5–10 m. The majority of theeels were assessed as being in the silver eel stage at the time of tagging. During the autumn months, the divingbehaviour, with frequent and large vertical excursions and periods at the surface, was similar to that seen inmigrating eels in the Baltic and Atlantic Ocean. In spring and summer, the behaviour differed, being dominated bymore gradual depth variations, implying that the eels reverted from silver eel migration behaviour to yellow eelforaging behaviour. Body weight declined during dormancy, but other studies of starvation over comparable timeperiods showed significantly higher average specific weight losses, implying that the Mälaren silver eels must havefed between the end of dormancy and recapture.
Place, publisher, year, edition, pages
2015. Vol. 24, no 4, 532-543 p.
Anguilla anguilla, hibernation, dormancy, data storage tag, annual activity cycle, starvation, growth rate
IdentifiersURN: urn:nbn:se:su:diva-113822DOI: 10.1111/eff.12165ISI: 000361010500004OAI: oai:DiVA.org:su-113822DiVA: diva2:787841