Assessment of fat reserves adequacy in the first migrant silver American eels of a large‐scale stocking experiment

Published source details Couillard C.M., Verreault G., Dumont P., Stanley D. & Threader R.W. (2014) Assessment of fat reserves adequacy in the first migrant silver American eels of a large‐scale stocking experiment. North American Journal of Fisheries Management, 34, 802-813.
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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 1997–2010 in a river system and estuary in Ontario, Canada (Couillard et al. 2014) found that translocated wild American eels Anguilla rostrata were smaller in size and had smaller egg cells (oocytes) than naturally occurring eels. Translocated wild eels had lower body mass (313–752 g) and length (531–781 mm) than naturally occurring eels (1,163–3,276 g, 824–1,173 mm). Additionally, translocated wild eels had smaller oocytes (diameter 0.21–0.29 mm) than naturally occurring eels (0.22–0.35 mm). Eye size, pectoral fin size and muscle lipid content were lower in translocated eels compared to naturally occurring eels, but digestive tract mass and water content were higher (see paper for details). In 2005–2010, approximately 6.8 million glass eels purchased from commercial fisheries on the coast were tagged and translocated 900–1,100 km to either Richelieu River or St. Lawrence River and Lake Ontario. In 1997–2001, wild juvenile eels (319–582 mm) captured on eel ladders on two dams in the St. Lawrence River were tagged and released upstream of the dams. In September–November 2010, translocated wild eels and naturally occurring eels were recaptured at the St. Lawrence Estuary by commercial fishers (using weirs at angles to the shoreline) during their seaward migration. Measurements from 51 translocated and 51 naturally occurring eels were compared.

(Summarised by: Vanessa Cutts)