What happens to glass eels after restocking in upland rivers? A long‐term study on their dispersal and behavioural traits

Published source details Nzau Matondo B., Séleck E., Dierckx A., Benitez J., Rollin X. & Ovidio M. (2019) What happens to glass eels after restocking in upland rivers? A long‐term study on their dispersal and behavioural traits. Aquatic Conservation: Marine and Freshwater Ecosystems, 29, 374-388.
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This study is summarised as evidence for the following.

	Action	Category
	Translocate wild eels to re-establish or boost native populations (‘stocking’ or ‘restocking’) Action Link

Translocate wild eels to re-establish or boost native populations (‘stocking’ or ‘restocking’)

A study in 2014–2017 in a river in southern Belgium (Nzau Matondo et al. 2019) reported that most tagged, translocated wild European eels Anguilla anguilla survived, dispersed from the release site and grew in size. During four years after release, 205 of 241 tagged, translocated eels (85%) were detected in the river. Detections were made up to 0.5 km downstream and 2.3 km upstream of the release site, although dispersal was limited by physical obstacles (see paper for details). Forty-seven translocated wild eels recaptured 1–3 years after release grew in length (average 31 mm/year). In 2013, wild glass eels (total 4,155 eels) were released in the Mosbeux River, 0.04 km upstream of its mouth. From November 2014 to September 2016, translocated eels recaptured along a 3-km stretch of the river during nine electrofishing sessions (using 40 x 40 cm diameter hand nets) were measured, radio-tagged, and released. Recaptured tagged eels were re-measured. Tagged eels were tracked 1–3 times/month (total 53 days) from December 2014 to May 2017.

(Summarised by: Anna Berthinussen)