Genetic and genomic impacts of escaped farmed salmon in Atlantic Canada: Evaluating the use of archived Atlantic salmon scales as a source of pre-impact DNA

Description

Aquaculture escapees can threaten the persistence and stability of wild salmon populations, with impacts occurring through both genetic and ecological interactions. Direct genetic interactions result from interbreeding of farm escapees with wild fish, potentially causing population-level changes including erosion of local adaptation and loss of fitness. However, the presence and magnitude of these genetic impacts are difficult to quantify, largely because pre-impact genetic baseline information is not available. Historically, monitoring protocols for Atlantic salmon included collecting scales for aging purposes; these archived scales represent an important source of pre-aquaculture DNA samples (i.e., genetic baseline). The main objective of this project was to explore various methodologies for analyzing archived scales for use in future studies that will compare the genetic information from pre- and post-aquaculture samples from Atlantic salmon in Atlantic Canada. The results of this study allow for the quantification of the extent of genetic impacts from escaped Atlantic salmon over time and in different areas.

Findings

Historically, Atlantic salmon scales were used for aging purposes and these archived scales could be a source of baseline DNA from before aquaculture in the region. Various DNA extraction methods were tested and extracted DNA was quantified and used for microsatellite genotyping. The success of these extraction techniques enable future comparison of pre- and post-aquaculture DNA samples from Atlantic salmon in Atlantic Canada. Baseline DNA samples will quantify the presence and magnitude of genetic impacts from escaped farmed salmon and better inform mitigation strategies.

Publications

DFO. 2016. Proposed Use of European-Strain Triploid Atlantic Salmon in Marine Cage Aquaculture in Placentia Bay, NL. DFO Can. Sci. Advis. Sec. Sci. Resp. 2016/034

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