Thursday, April 8, 2004
1:30 to 3:00
The impacts of climate variation and change events on threatened salmon populations in southern British Columbia: Implications for conservation and restoration
We have examined behavioral and physiological responses of salmon (Oncorhynchus
spp.) to annual and seasonal
variations in thermal regimes experienced at selected life history stages.
This enabled us to identify underlying sets of "decision rules" as biophysical
models of how aquatic thermal regimes may influence life history events
and production variations exhibited by several threatened or vulnerable
populations of salmon in southern British Columbia.
These biophysical models were then applied in a retrospective analysis of
the potential contributions of climate variation and change (CVC) events
to historic population trends exhibited by salmon stocks at risk.
Results indicate a pervasive influence of CVC events on several life history stages of the subject populations. Climate warming impacts included:
- delays to adult migration, adult spawning and timing of egg hatch,
- increased spatial and temporal restrictions on juvenile rearing habitat or access to food supplies, and
- alteration of the timing of seaward migration by salmon smolts.
Our analyses suggest that CVC effects are not only temporally variable but also appear to be mediated by processes associated with "warm-phase" and then "cold-phase" periods of the Pacific Interdecadal Oscillation. Future "climate warming" episodes will complicate the manageability and threaten the sustainability of many salmon populations in the southern end of their range. This recommends the development of strategies that minimize the impact of uncertain CVC scenarios on the resilience of the salmon resource and that maximize our adaptive capacity for both short and long-term fisheries planning and management decisions. New integrated assessment and resource management models will be required to deal effectively with the complexities of impact and adaptation responses of natural resources, managers and stakeholders to future CVC events.
Dr. Hyatt is a research scientist at Fisheries and Oceans Canada’s (DFO) Pacific Biological Station (PBS) in Nanaimo, British Columbia. He has a BSc from the University of Windsor (1971) and a PhD from the University of British Columbia (1980). He has worked as a teacher (Okanagan University College faculty member 1976-1978), environmental consultant (Western Canada and the U.S., 1978-1980) and fisheries scientist (DFO 1981-present).
Kim holds adjunct faculty appointments at the University of British Columbia and the University of New Brunswick. He also serves as: a science advisor and manager for the National Fisheries Sector Office of the Canadian Climate Impacts and Adaptation Research Network (C-CIARN Fisheries); vice president of the Canadian Aquatic Resources Section of the American Fisheries Society; research director for the non-profit Northwest Ecosystems Institute, and as a Canadian representative on the International Union for the Conservation of Nature’s (IUCN) salmonid species group.
Dr. Hyatt currently heads the Salmon in Regional Ecosystems Program at
Fisheries and Oceans Canada’s Pacific Biological Station. His current
research interests are focused on (1) the status of salmon populations in
Canada’s Pacific Region, (2) climate variation and change effects
on salmon in freshwater and marine ecosystems, and (3) development of decision
support tools to improve fisheries management.