Regimes of chlorophyll-a in the Coral Sea: implications for evaluating adequacy of marine protected areas

Spatial management of the highly dynamic pelagic realm, and the highly mobile species it supports, requires dynamic processes to be incorporated into reserve design. To achieve this, planners need information on how these processes vary across space and time, and how this variation relates to species of conservation interest. This study presents a new method of quantifying variability that captures both between- and within-year changes in variables of interest. We applied this method to remotely-sensed chlorophyll-a in the Coral Sea to find five distinct regimes of variation that serve as surrogates for assemblages of species of conservation interest. We performed a gap analysis to determine protection of the regimes both internationally and nationally within Australia's network of marine reserves in the Coral Sea. We also identified key areas for protection within each regime, in terms of chlorophyll-a variability and species associations, and examined their protection status. Depending on conservation objectives, reserve systems that span multiple national jurisdictions and a rezoning of Australian national waters might be necessary to meet protection requirements for the regimes and for key areas within them. The current suspension and review of the Coral Sea Commonwealth Marine Reserve management plans and the recent proclamation of New Caledonia's as yet unzoned Coral Sea Nature Park offer planners an opportunity to incorporate dynamic processes into conservation planning for the Coral Sea. The method we present can be applied at other locations for time-series of any variable/s of interest, aiding the spatial management of dynamic features in both marine and terrestrial contexts.