Líffræðifélag Íslands
Líffræðiráðstefnan 2015
Erindi/veggspjald / Talk/poster E81
Ólafur Patrick Ólafsson (1), Gísli Már Gíslason (2), Guðni Guðbergsson (3)
1. og 2. Háskóli Íslands, 3. Veiðimálastofnun
Kynnir / Presenter: Ólafur Patrick Ólafsson
Tengiliður / Corresponding author: Ólafur Patrick Ólafsson (patrick@hi.is)
Brown trout (Salmo trutta) is abundant in the Hengladalsá river and its tributary streams in the Hengill geothermal area. Some of these tributaries are cold (2-8°C) , while others are geothermally heated (12-42°C). The Hengill area is unique among geothermally active areas in that in several locations geothermally heated and cold streams run parallel to each other, separated by only a few metres. During the spring of 2006, 400 brown trout were caught in 2 cold and 3 warm (12-23°C) tributaries, as well as in Hengladalsá river itself, tagged with PITs (Passive Integrated Transponders), and released at the site where they were caught. Each PIT has a unique code that is identified by an appropriate scanner when exposed to a low frequency signal, positively identifying each tagged individual. The streams were scanned systematically at fortnightly intervals during the summer of 2006 and 2007, and when conditions permitted during the intervening winter. Many brown trout were found in geothermally affected streams, but very few in cold streams. This is presumably the result of different invertebrate compositon in geothermal streams than in cold ones. Furthermore, there appears to be no movement of brown trout between Hengladalsá river and cold streams, while there does appear to be movement between it and warm streams.