Climate change will alter the future suitability of eastern Canadian marine protected areas for Atlantic cod
Climate change presents challenges for marine conservation areas that often have fixed boundaries.
As marine habitat changes, a conservation area may no longer be suitable for certain species, forcing them to relocate.
Using a group of global climate models we show changes in ocean oxygen and temperature from 1993 to 2100 for the eastern Canadian coastal shelf, improving the resolution of previous modelling in this region.
Read this open access paper on the FACETS website.
With these models, we forecasted egg survival, juvenile growth, and spawning (reproducing) habitat limitations in terms of ocean temperature and oxygen for Atlantic cod, a species of ecological, economical, and cultural importance. We then mapped projected changes in these habitats in relation to existing marine conservation areas.
Northern areas off of eastern Canada are predicted to become better habitat for cod eggs as these areas warm. Ideal habitat for juvenile cod growth will likely shift both north- and eastward and also increase in area due to warmer waters.
Cod spawn in deeper water near the ocean floor, where lower oxygen concentrations will limit habitat suitability for spawning adults more so than for eggs or juveniles which occur at shallower depths (closer to the surface).
Good spawning habitat will decrease across the entire region due to decreases in bottom oxygen, but declines will be less in northern areas as they warm.
To help managers understand overall changes, we combined egg, juvenile and spawning habitat parameters. This combined index predicts declines in overall habitat quality in the southern conservation areas largely due to decreases in oxygen, and increases in good central and northern conservation areas due to ocean warming in this cold-water system.
Both maintaining existing marine conservation areas and development of new ones in improving habitats (e.g. along the Labrador Shelf) will thus be important to ensure Canada’s protected areas remain useful to Atlantic cod into the future.
Ocean oxygen is forecasted to be a limiting factor in eastern Canada for species like Atlantic cod and should be monitored to understand changes in ocean health.
Read the paper — Climate bottlenecks off Newfoundland and Labrador for Atlantic cod in relation to eastern Canadian marine protected areas by Julie A. Thayer, Trond Kristiansen, Cassandra A. Konecny, Gammon Koval, Rodd Laing, and David Côté.
