The specificity of marine ecological indicators to fishing in the face of environmental change: A multi-model evaluation

Shin, Yunne-Jai ... et al.-- This is a contribution to the IndiSeas Working Group, co-funded by IOC-UNESCO and the Euromarine Consortium in 2015.-- 10 pages, 4 figures, 2 tables, supplementary data https://doi.org/10.1016/j.ecolind.2018.01.010Ecological indicators are widely used to characterise ecosystem health. In the marine environment, indicators have been developed to assess the ecosystem effects of fishing to support an ecosystem approach to fisheries. However, very little work on the performance and robustness of ecological indicators has been carried out. An important aspect of robustness is that indicators should respond specifically to changes in the pressures they are designed to detect (e.g. fishing) rather than changes in other drivers (e.g. environment). We adopted a multi-model approach to compare and test the specificity of commonly used ecological indicators to capture fishing effects in the presence of environmental change and under different fishing strategies. We tested specificity in the presence of two types of environmental change: “random” representing interannual climate variability and “directional” representing climate change. We used phytoplankton biomass as a proxy of the environmental conditions, as this driver was comparable across all ecosystem models, then applied a signal-to-noise ratio analysis to test the specificity of indicators with random environmental change. For directional change, we used mean gradients to apportion the quantity of change in the indicators due to fishing and the environment. We found that depending on the fishing strategy and environmental change, ecological indicators could range from high to low specificity to fishing. As expected, the specificity of indicators to fishing almost always decreased as environmental variability increased. In 55–76% of the scenarios run with directional change in phytoplankton biomass across fishing strategies and ecosystem models, indicators were significantly more responsive to changes in fishing than to changes in phytoplankton biomass. This important result makes the tested ecological indicators good candidates to support fisheries management in a changing environment. Among the indicators, the catch over biomass ratio was most often the most specific indicator to fishing, whereas mean length was most often the most sensitive to change in phytoplankton biomass. However, the responses of indicators were highly variable depending on the ecosystem and fishing strategy under consideration. We therefore recommend that indicators should be tested in the particular ecosystem before they are used for monitoring and management purposesL.J.S was supported through the South African Research Chair Initiative, funded through the South African Department of Science and Technology and administered by the South African National Research Foundation. J.E.H., L.V., and Y.J.S were funded by the EMIBIOS project (FRB Fondation pour la Recherche sur la Biodiversité, contract n°APP-SCEN-2010-II). J.E.H. was supported by a Beaufort Marine Research Award carried out under the Sea Change Strategy and the Strategy for Science Technology and Innovation (2006–2013), with the support of the Marine Institute, funded under the Marine Research Sub-Programme of the Irish National Development Plan 2007–2013. L.J.S and Y.J.S. were funded by the European project MEECE (FP7, contract n°212085). M.C. was supported by a Marie Curie CIG grant to BIOWEB project and the Spanish Research Program Ramon y Cajal. Funding from CSIRO and the Australian Fisheries Research and Development Corporation on behalf of the Australian Government supported the development of Atlantis-SE. J.J.H was supported by the UK Natural Environment Research Council and Department for Environment, Food and Rural Affairs under the project MERP: Grant No. NE/L003279/1, Marine Ecosystems Research ProgrammePeer Reviewe

The specificity of marine ecological indicators to fishing in the face of environmental change: A multi-model evaluation

International audienceEcological indicators are widely used to characterise ecosystem health. In the marine environment, indicators have been developed to assess the ecosystem effects of fishing to support an ecosystem approach to fisheries. However, very little work on the performance and robustness of ecological indicators has been carried out. An important aspect of robustness is that indicators should respond specifically to changes in the pressures they are designed to detect (e.g. fishing) rather than changes in other drivers (e.g. environment). We adopted a multi model approach to compare and test the specificity of commonly used ecological indicators to capture fishing effects in the presence of environmental change and under different fishing strategies. We tested specificity in the presence of two types of environmental change: \textquotedblleftrandom\textquotedblright, representing interannual climate variability and \textquotedblleftdirectional\textquotedblright, representing climate change. We used phytoplankton biomass as a proxy of the environmental conditions, as this driver was comparable across all ecosystem models, then applied a signal-to-noise ratio analysis to test the specificity of indicators with random environmental change. For directional change, we used mean gradients to apportion the quantity of change in the indicators due to fishing and the environment. We found that depending on the fishing strategy and environmental change, ecological indicators could range from high to low specificity to fishing. As expected, the specificity of indicators to fishing almost always decreased as environmental variability increased. In 55-76% of the scenarios run with directional change in phytoplankton biomass across fishing strategies and ecosystem models, indicators were significantly more responsive to changes in fishing than to changes in phytoplankton biomass. This important result makes the tested ecological indicators good candidates to support fisheries management in a changing environment. Among the indicators, the catch over biomass ratio was most often the most specific indicator to fishing, whereas mean length was most often the most sensitive to change in phytoplankton biomass. However, the responses of indicators were highly variable depending on the ecosystem and fishing strategy under consideration. We therefore recommend that indicators should be tested in the particular ecosystem before they are used for monitoring and management purposes