SS1.05 How Will Aquatic Ecosystems Respond to Climate Change?
Date: Tuesday, June 11, 2002
Time: 2:15:00 PM
Location: Oak Bay
HealeyM, Institute for Resources and Environment, UBC, , Canada,
The effects of global warming on marine and freshwater fish stocks is a subject of considerable concern to both biologists and fishery managers. We have examined cumulative effects of global warming on sockeye salmon from the Fraser River drainage in BC but our results can be extrapolated to other species and locations. Salmon are useful models to explore the broad implications of global change because they integrate across a wide range of freshwater and marine environments throughout their life. Under likely IPCC global warming scenarios, temperatures in the freshwater habitats of Fraser sockeye will increase 3-4 C, summer stratification of their lacustrine nurseries will be longer and more intense, and annual food production may be diminished. In their marine habitats, temperature will increase 2-3 C, circulation in the Alaskan gyre will weaken, mixed layer depth will be shallower and food production may be reduced. Changes in the thermal environment of salmon in particular will effect the ways in which the fish allocate the energy in their food resources among the ecologically important functions of maintenance, growth and reproduction. Ecological energetics analysis indicates that these changes will lead to slower growth and poorer survival at all life stages that accumulate over time and potentially spell the end of commercially valuable salmon from the Fraser.