HALIFAX - A new study predicts a steep decline in global fish populations, including species in Atlantic Canada, by the end of the century if unchecked greenhouse gas emissions continue.
The 108-page report, published last week by the Food and Agriculture Organization of the United Nations, projects that with an average temperature increase of 3 to 4°C, fish biomass could decline by over 30% by 2100 in 48 countries. China, the world's largest seafood consumer, is expected to see a 31% loss in catches.
In a low carbon emissions scenario (1.5 to 2°C warming), the report predicts less than a 10% global loss of fish. The study measures biomass as the total amount of fish in a specific body of water, using grams of carbon per square metre of water.
Andrea Bryndum-Buchholz, a marine ecologist at Memorial University and one of 41 contributors to the study, says that in nine different projection models, Canadian fisheries are found to be vulnerable as water temperatures rise in the northwest Atlantic.
"All these models agree that fish biomass is going to decline in certain areas because water temperature is increasing," she said. The study shows that three-quarters of the East Coast's protected marine areas fall within climate change hotspots, where waters are expected to warm at higher rates.
Bryndum-Buchholz notes that this has serious implications for the region's fishers, who could face significant challenges in the worst-case emission scenarios. "The fishing industry is super important here. It needs to be sustainable," she said. If climate change continues at its current pace, it could lead to fishery closures, harming a key part of the region's economy.
Bryndum-Buchholz suggests that governments adopt a risk-based approach tailored to each region, carefully monitoring biomass, animal behavior, and water temperature. This approach requires significant investment and would involve adjusting allowable catches at early signs of decline, enforcing catch restrictions to prevent fishing juvenile fish, and adjusting marine protected areas to respond to climate change.
Increased water temperatures can influence migration and breeding habits. For example, more lobsters are moving away from waters in Maine as the Atlantic waters warm. Areas in Atlantic Canada expected to experience significant warming and biomass declines include the Scotian Shelf, the Laurentian Channel, and the Grand Banks. The Gulf of St. Lawrence, which borders all four Atlantic provinces and Quebec, is the fastest warming area.
Source: CTV News Atlantic (Jul 17, 2024). Fish biomass loss possible in Atlantic Canada amid rising emissions, researcher says. https://atlantic.ctvnews.ca/fish-biomass-loss-possible-in-atlantic-canada-amid-rising-emissions-researcher-says-1.6967177
