Competition between hatchery-raised and wild brown trout Salmo trutta in enclosures – do hatchery releases have negative effects on wild populations?
Article first published online: 1 FEB 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Munksgaard
Ecology of Freshwater Fish
Volume 18, Issue 2, pages 261–268, June 2009
How to Cite
Vehanen, T., Huusko, A. and Hokki, R. (2009), Competition between hatchery-raised and wild brown trout Salmo trutta in enclosures – do hatchery releases have negative effects on wild populations?. Ecology of Freshwater Fish, 18: 261–268. doi: 10.1111/j.1600-0633.2008.00343.x
- Issue published online: 15 MAY 2009
- Article first published online: 1 FEB 2009
- Accepted for publication October 16, 2008
- experimental design;
- boreal river;
- stomach flushing;
- winter ecology
Abstract – We compared the growth and prey consumption of juvenile hatchery and wild brown trout of similar genetic origin in 12 wire mesh cages in a natural river in North-Eastern Finland. Wild trout started feeding shortly after the start of the experiment, and clearly earlier than novel hatchery trout, but ate less in the presence of hatchery trout. When accompanied with wild trout, novel hatchery trout started to feed earlier, consumed more live prey, and lost less weight than when in allopatry. Hatchery trout grew more slowly than wild trout. To our knowledge, this is the first study to show that hatchery trout benefit from the presence of wild, experienced trout in a complex semi-natural environment. However, our results also indicate that the benefits to hatchery fish are not transferred to wild fish, and ultimately that care should be exercised in management actions when using hatchery trout to supplement wild populations. On the other hand survival potential of the novel hatchery brown trout could be better in the wild when also undomesticated trout are present.