Gros Morne National Park of Canada

Atlantic Salmon Stock Assessment for Trout River (2001 and 2002), Gros Morne National Park of Canada, Newfoundland

Background

Given the very low salmon numbers and the potential impacts of competing rainbow trout, there are concerns about the ecological integrity of the Trout River system.

Trout River is a scheduled salmon river located in Salmon Fishing Area (SFA) 14A. It has a total watershed area of 258 km ² of which 143 km ² or 55 % is contained within the boundaries of Gros Morne National Park.

Trout River has experienced a wide range of catch, as well as catch per unit effort, during the period 1974-2000 [Department of Fisheries and Oceans (DFO) licence stub return data, unpublished] and little is known of historical populations of salmon in the system. In addition, anglers have frequently reported the capture of rainbow trout, an exotic species introduced from the Pacific, over the past number of years. Rainbow trout are potential competitors of salmon and can displace salmon from some habitats. It was not clear whether the rainbow trout had established a breeding population in the Trout River system.

Goals

• To determine the numbers of adult salmon, brook trout, and rainbow trout entering the Trout River system.

• To remove all rainbow trout and sample them to determine their reproductive status.

• To determine whether rainbow trout are successfully reproducing in Trout River.

Project Description

A fish counting fence was installed on the main branch of Trout River approximately 2 km upstream from the river mouth. The fence operated during the summers of 2001 and 2002.

A total of 51 adult anadromous salmon (consisting of 15 large [ > 63 cm fork length] and 36 small [ <63 cm fork length]) returned to the river in 2001. In 2002, a total of 53 adult anadromous salmon (12 large and 41 small) returned. Using standard DFO formulas and some values taken from nearby rivers, we calculated that Trout River is reaching approximately 25% of its salmon conservation requirements. A number of rainbow trout were also captured both at the fence and through electrofishing. Juvenile rainbow trout were found in The Feeder, indicating that the rainbows are successfully reproducing in the system.

Given the very low salmon numbers and the potential impacts of competing rainbow trout, there are concerns about the ecological integrity of the Trout River system.

Project Team