Trend analysis of indicators: A comparison of recent changes in the status of marine ecosystems around the world

13 pages, 4 figures, 6 tablesBlanchard, J. L., Coll, M., Trenkel, V. M., Vergnon, R., Yemane, D., Jouffre, D., Link, J. S., and Shin, Y-J. 2010. Trend analysis of indicators: a comparison of recent changes in the status of marine ecosystems around the world. - ICES Journal of Marine Science, 67: 732-744.Time-series of ecological and exploitation indicators collected from 19 ecosystems were analysed to investigate whether there have been temporal trends in the status of fish communities. Using linear and non-linear statistical methods, trends are reported for six indicators (mean length of fish in the community, mean lifespan, proportion of predatory fish, total biomass of surveyed species, mean trophic level of landings, and inverse fishing pressure), and the redundancy of these indicators across ecosystems is evaluated. The expected direction of change for an ecosystem that is increasingly impacted by fishing is a decline in all indicators. A mixture of negative and positive directions of change is recorded, both within and among all ecosystems considered. No consistent patterns in the redundancy of the ecological indicators across ecosystems emerged from the analyses, confirming that each indicator provided complementary information on ecosystem status. The different trends in indicators may reflect differing historical exploitation patterns, management, and environmental regimes in these systems. Commitment to monitoring programmes and development of system-specific baseline, target, and threshold reference levels are required. Improved understanding of the responsiveness and performance of ecological indicators to management actions are needed to address adequately whether ecosystems are recovering from, or being further impacted by, fishing, and whether management targets are being met. The relative effects of multiple environmental and ecological processes as well as multiple human-induced stressors that characterize exploited ecosystems also need to be quantifiedThe IndiSeas WG was funded by the European Network of Excellence EUR-OCEANS (FP6, contract 511106), the European collaborative project MEECE (Marine Ecosystem Evolution in a Changing Environment; FP7, contract 212085), and the IRD (Institut de Recherche pour le Développement). JLB was partially funded by EU IMAGE (FP6 contract 044227) and UK Defra contract M1001, and was supported by the NERC Centre for Population Biology Visiting Researchers Programme. MC was partially supported financially by a postdoctoral fellowship from the Spanish Ministry of Science and Technology, by the European Community Marie Curie Postdoctoral Fellowship through the International Outgoing Fellowships (IOF; Call: FP7-PEOPLE-2007-4-1-IOF), and by Dalhousie University (Halifax, Canada). Funding to pay the Open Access publication charges for this article was provided by the European collaborative project MEECE (Marine Ecosystem Evolution in a Changing Environment; FP7, contract 212085)Peer Reviewe