Gros Morne National Park of Canada

Impacts of exotic rainbow trout in the Trout River watershed, Gros Morne National Park of Canada, Newfoundland.

Background

Juvenile rainbow trout ( Oncorhynchus mykiss )
© Parks Canada / Tom Knight, 2001

Rainbow trout, which have escaped from aquaculture, have been observed in increasing numbers in six scheduled salmon rivers on the west coast of Newfoundland, including Trout River in GMNPC. This increase is coincidental with the expansion of marine cage rearing of rainbow trout in Bay d'Espoir, NF and Cape Breton Island, NS. Biological samples taken by the Department of Fisheries and Oceans (DFO) in 2000 indicated that at least some of these fish were reproductively viable rainbow trout, raising the possibility that rainbows could establish self-sustaining populations in west-coast rivers. Since rainbow trout are exotic to Newfoundland, there is a high probability that these fish could have a serious negative impact on native salmonids, brook trout and Atlantic salmon.

Trout River Pond
© Parks Canada / Tom Knight, 2001

This project examines the potential threat of rainbow trout to native salmonids of Trout River, including the possibility that rainbow trout may be successfully spawning in the Trout River watershed. Atlantic salmon stocks in Trout River are presently at low levels and their habitat is vulnerable to intrusion by an exotic species. In partnership with DFO and the Town of Trout River, we operate a fish-counting fence on Trout River, to capture and remove rainbow trout. We also conduct in-river surveys to identify where rainbow trout are located in the watershed.

Goals

• Determine the potential impacts of exotic rainbow trout on Atlantic salmon in Trout River.

• Determine the biological characteristics of rainbow trout invading Trout River.

Project Description

Electrofishing
© Parks Canada / Tom Knight

During 2001 and 2002, a fish counting fence was used to intercept rainbow trout migrating upstream in Trout River. Mature, fertile rainbow trout were found to be entering the watershed. Extensive in-river surveys located many rainbow trout juveniles, confirming that rainbow trout have successfully established a breeding population in GMNPC. Further study has been aimed at identifying habitat use and potential competitive interactions among rainbow trout and the native salmonids, both brook trout and Atlantic salmon.

Project Team