How Ocean Warming Intensifies Predation
Across 115 degrees of latitude in North and South America, a large-scale study has shown that warmer ocean temperatures are linked to stronger predation by fish and noticeable shifts in invertebrate prey communities. Published in Science, the findings highlight one of the ways climate change could reshape marine ecosystems.
A Landmark Collaboration
Led by researchers from the Smithsonian Environmental Research Center, the project involved 57 institutions working at 36 nearshore sites across 11 countries. Marine biologist Gail Ashton describes the effort as a massive step forward in understanding how predation varies geographically, made possible through broad collaboration.
The Experiments
During the summer months, scientists conducted three standardized experiments:
- Bait consumption test: Dry squid bait was used to measure predation intensity over one hour.
- Community development panels: PVC panels, some caged and others exposed, were submerged for three months to track invertebrate growth.
- Predation on established communities: After 10 weeks underwater, half of a set of panels was uncaged to measure predator effects on existing prey.
Findings Across Latitudes
The results revealed a clear trend—warmer waters increased both predation intensity and prey biomass loss:
- At cooler sites with average summer temperatures around 9°C, bait loss was minimal.
- At tropical sites with waters near 31°C, bait consumption exceeded 10 percent in one hour.
- Differences in biomass between caged and uncaged panels rose from near zero to more than 300 grams across the temperature gradient.
Interestingly, at higher latitudes, predators had little impact on invertebrate communities, suggesting that other factors currently play a more important role there.
Expert Perspectives
Marine ecologist Jay Stachowicz praised the scope of the study, noting that scientists often lack large-scale data on predation. While the experimental design standardized habitats by using floating panels, it excluded seafloor predators like crabs and snails, which could also be influential. Both Stachowicz and Ashton emphasized the need for future research to clarify whether increased predation in warmer waters is due to more predators, higher metabolic activity, or shifts in species composition.
Implications for Conservation
Understanding how predation patterns shift with rising ocean temperatures could guide conservation efforts, from identifying areas less vulnerable to overfishing to designing marine protection strategies. Ashton notes that pinpointing key predators and regional differences will be essential to predicting ecosystem changes. While this study offers important insights, it is only one piece of the complex puzzle of how marine communities may transform in the face of climate change.