Detecting hybridization among wild and farmed escaped Atlantic salmon in southern Newfoundland: Field collections

Description

Aquaculture escapees represent a continued threat to the genetic integrity of wild populations, and have been shown to interbreed with wild fish, which can impact local adaptation. In southern Newfoundland, wild Atlantic salmon populations remain at record lows and their status is considered "threatened" by COSEWIC. Potential impacts associated with the developing aquaculture industry cannot be ruled out as a contributing factor on the survival of wild fish. In 2013, a large escape event (>20,000 individuals) occurred in southern Newfoundland where there were reports of mature escapees in local rivers. Given the magnitude of this escape event, this study was designed to determine if interbreeding occurred (i.e., hybridization) and if the samples of young-of-the-year Atlantic salmon contained a mixture of wild and hybrid individuals.

Findings

The aim was to collect young of the year Atlantic salmon following a large (>20,000 individuals) escape event in 2013 in southern Newfoundland. This escape event was equal to or greater than the estimated wild salmon population in the region. In total 2000 juvenile Atlantic salmon were collected, fin clipped and tissue preserved in ethanol. Samples were taken from 16 locations throughout southeastern Newfoundland. Future genomic screening of these samples will be used to quantify the rates of hybridization and evaluate the genetic impact of aquaculture escapees on wild populations in Newfoundland and Labrador.

Publications

N/A

Program Name

Program for Aquaculture Regulatory Research (PARR)

Year(s)

2014 to 2016

Principal Investigator(s)

Ian Bradbury
Research Scientist, Salmonids Section, Science Branch, Northwest Atlantic Fisheries Centre
80 East White Hills Road, St. John’s, Newfoundland and Labrador
Email: Ian.Bradbury@dfo-mpo.gc.ca

Team Member(s)

Lorraine Hamilton

Patrick O'Reilly

Geoff Perry