Individual study: Impact of fish stocking on Eurasian otter (Lutra lutra) densities: A case study on two salmonid streams
Sittenthaler M., Bayerl H., Unfer G., Kuehn R. & Parz-Gollner R. (2015) Impact of fish stocking on Eurasian otter (Lutra lutra) densities: A case study on two salmonid streams. Mammalian Biology, 80, 106-113
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Provide supplementary food to increase reproduction/survival
A site-comparison study in 2011 along two rivers in Austria (Sittenthaler et al. 2015) found that on a river stocked with fish for angling, densities of resident adult Eurasian otters Lutra lutra were not higher than those on an unstocked river. No statistical analyses were performed. Resident adult otter density on the stocked river (0.23 otters/km) was similar to that on the unstocked river (0.22 otters/km). However, including juvenile and non-resident otters, a slightly higher density was found on the stocked river (0.37 otters/km) than on the unstocked river (0.33 otters/km). Two river stretches, with similar hydromorphology, were studied. One (21.5 km long) was stocked with fish from a hatchery in April–September each year. The other (18.3 km long) was not stocked. Otter spraints were collected daily for five days during three visits from February–April 2011. Individual otters were identified by genetic analysis of faeces. Forty-eight faeces were successfully used to genetically identify individuals from the stocked river and 33 from the unstocked river.
(Summarised by Nick Littlewood)