Arctic Fish Genomics as 'Sentinels' of Ecosystem Integrity and Change

Description

Climate change and increased variability in the western Arctic is significantly affecting freshwater, anadromous and marine fishes and their respective habitats and ecosystems. With this pressing issue in mind, there were a number of priorities that this project addressed:

1. research to underpin the sustainable management of Arctic fisheries (e.g., Dolly Varden Integrated Fisheries Management Plan),
2. assessing effects/risks of climate change (e.g., threats to native species from potential colonizers),
3. assessing effects/risks of industrial development on Arctic aquatic ecosystems (e.g., adaptive capacity of fishes to habitat impacts from gas pipeline development along the Mackenzie River Valley and gas and oil development in Beaufort Sea), and
4. management of species at risk or under assessment by the Government of Canada’s Committee on the Status of Endangered Wildlife in Canada (e.g., Dolly Varden - Special Concern; Bull Trout - Threatened).

The work also developed the capacity of the regional genetics laboratory to support science delivery for regional fisheries management.

Many northern fish species, particularly chars and whitefishes (i.e., native salmonids), support large freshwater and coastal aboriginal subsistence fisheries in the western Arctic. Other fish species are valuable components of the food web and sustain other larger animals, including seals and beluga whales. These latter fish species, including Arctic Cod, northern Dolly Varden, Broad Whitefish, and Inconnu are adapted to Arctic environments but are vulnerable to man-made stressors such as climate change, habitat alteration and industrial development. Climate change in particular raises the risk of colonization of Arctic habitats by sub-Arctic species. Colonizers potentially affect resident species through hybridization, direct competition or predation, disease and parasite introductions.

The genomics focus in this project was on profiling key sentinel colonizer species:

1. Bull Trout as a sentinel fish species in the Mackenzie Valley;
2. Pacific salmons as sentinel colonizers of coastal Canadian Arctic rivers, and;
3. Pacific Cod as a sentinel of Beaufort Sea ecosystem change.

Genetic effects of potential colonizing fish species (herein 'sentinel species') were documented; profiling the genetic variety of these potential colonizers provided a baseline of their genetic makeup. When placed in the context of the diversity of Arctic species, potential hybridization with resident species was determined. The project also examined expectations regarding the potential source populations and consequences of their colonization of the area. Resulting data will also inform diversity issues under Species at Risk Act (SARA) responsibilities, and aid in monitoring species shifts associated with climate change.

Results:

Bull Trout : The genetic variation of Bull Trout in Canada’s North, representing migratory and non-migratory type fish, has been determined. Genetic markers are commonly used by biologists to not only distinguish different populations within species but also explain the evolutionary relationships between different species. Therefore, not only have different Bull Trout populations been identified, but the genetic variation across a number of other species will be used in the development of specific genetic markers. These markers will allow assessment of hybridization over wide geographic areas, provide the basis for future forensic identification and used to monitor the status of species in the North.

Pacific Salmon : Of the five species of Pacific salmon, Chum Salmon exhibit at least one established population upstream in the Mackenzie River. Both the overall incidence (i.e., population abundance) and the geographical extent of reproducing populations within the Mackenzie River basin appear to be increasing for this species. The remaining four salmon species are presently represented in Canadian Arctic waters as roving occurrences; of these, Pink Salmon exhibit the greatest probability for initial colonization success. Work is progressing to determine source-of-origin and stock structure of salmon in the Mackenzie River area, and assess the consequences of colonizations.

Pacific Cod as a Sentinel Species : A series of diagnostic genetic tests have been identified and continue to be developed to differentiate cod species common in the Canadian Arctic. The continued development of new tests is in response to queries from researchers requesting genetic means of distinguishing species difficult to identify using physical characteristics. Sub-samples of Arctic Cod from previous work have been analyzed at the University of Victoria using microsatellite (repetitive DNA) testing; initial results have been synthesized into wider geographic analyses. Results based upon these tests indicate population structuring at two levels – large-scale differentiation into Asian and North American groups, and regional-scale differentiation within North America into an eastern and a western group. Further complexities at the area-scale (i.e., Beaufort and Chukchi seas) also appear to exist but require further work to resolve.

Program Name

Genomics Research and Development Initiative (GRDI)

Year(s)

2011 - 2014

Principal Investigator(s)

Jim Reist
Fisheries and Oceans Canada