Exploring the potential effects of climate change on the Western Scotian Shelf ecosystem, Canada

• We model the western Scotian Shelf to explore potential effects of climate change.
• The effect vary among species but would lead to 19–29% decline in total biomass.
• Results suggest a 20–22% decrease in catches in the next 50 years.
• Decrease in exploitation rate could help ameliorate the decline in biomass.

Climate change is expected to cause profound changes in marine ecosystems that will vary in magnitude and effect among regions. We explore the potential effects of climate change on the western Scotian Shelf ecosystem in eastern Canada using an ecosystem model and two scenarios of climatic changes. The model includes the effects of temperature, pH, oxygen, decreased primary productivity and change in zooplankton size structure. These factors had differential, and sometimes opposing additive effects on the functional groups and species. The results also illustrate how the effects of climate change can be further enhanced or ameliorated by predator–prey interactions. At the individual species or functional group level, some effects were negligible, but at the ecosystem level, the combined predicted effect of climate change on the western Scotian Shelf led to a reduction in biomass of 19% to 29% with an associated decrease in catches of 20% and 22%. Dramatic declines in biomass due to climate drivers could be alleviated in part by a 50% decrease in exploitation rate.