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Reconciling differences in trophic control in mid-latitude marine ecosystems
Kenneth T Frank1, Brian Petrie, Nancy L Shackell
1Ocean Sciences Division, Department of Fisheries and Oceans, Bedford Institute of Oceanography, PO Box 1006, Dartmouth, NS, Canada B2Y 4A2. frankk@mar.dfo-mpo.gc.ca
Ecology Letters
|September 16, 2006
Summary
Marine ecosystems show varied trophic control, shifting from bottom-up in the south to top-down in the north. This spatial variance in trophic control influences fishery yields and ecosystem stability.
Area of Science:
- Marine Ecology
- Fisheries Science
- Ecosystem Dynamics
Background:
- Fishery yields have been linked to primary productivity, suggesting bottom-up control in marine systems.
- Previous studies often lacked dynamic analysis of this bottom-up control relationship.
- Understanding trophic control is crucial for sustainable fisheries management.
Purpose of the Study:
- To investigate the spatial variance of trophic control in marine ecosystems.
- To examine the dynamic relationship between primary productivity and fishery yields.
- To develop a model for trophic control dynamics.
Main Methods:
- Analysis of time series data from nine exploited regions in the western North Atlantic.
- Empirical observation and statistical analysis of ecological data.
- Development of a simplified trophic control diagram.
Main Results:
- Evidence of spatial variance in trophic control across the western North Atlantic.
- Northern areas exhibited top-down control, southern areas showed bottom-up control, and intermediate areas displayed a transition.
- Species diversity and ocean temperature correlated with the pattern of trophic control.
Conclusions:
- Trophic control in marine ecosystems is spatially variable, not uniformly bottom-up.
- Ecosystem stability is influenced by the interplay of compensatory population dynamics and demographic rates.
- The findings necessitate a nuanced approach to fisheries management considering regional trophic dynamics.
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