Potential impacts of ocean warming on the trophic control of a threatened marine ecosystem

Trophic controls (top-down control via predation pressure and bottom-up control via resource limitation) determine how ecosystems work and shape the approach of managing living resources. However, current research on trophic control is limited to certain species groups, and little is known about its response to climate changes and anthropogenic stressors. In this study, we aimed to evaluate the potential impacts of ocean warming on the trophic control in a heavily exploited marine ecosystem, and evaluate the effects of fishing on the sensitivity of trophic control mechanisms. Based on ecological network analysis theory, we developed the Trophic Control Coefficient as an index to directly assess the pattern and strength of trophic control at the whole ecosystem scale. Results showed that the changes in trophic control would be negligible under the SSP1-2.6 climate scenario, whereas the increased temperature would largely enhance the existing bottom-up control in the ecosystem under the SSP5-8.5 scenario. Moreover, fishing could increase the sensitivity of trophic control to climate warming with a nonlinear pattern, and a 50% reduction of current fishing pressure might be a critical threshold for supporting ecosystem stability. Our findings advance the understanding of the mechanism of warming effects on marine ecosystems, and highlight the role of fisheries management in strengthening ecosystem resilience to climate changes.