The United Nations General Assembly in 2006 and 2009 adopted resolutions that call for the identification and protection of vulnerable marine ecosystems (VMEs) from significant adverse impacts of bottom fishing. While general criteria have been produced, there are no guidelines or protocols that elaborate on the process from initial identification through to the protection of VMEs. Here, based upon an expert review of existing practices, a 10-step framework is proposed: 1) Comparatively assess potential VME indicator taxa and habitats in a region; 2) determine VME thresholds; 3) consider areas already known for their ecological importance; 4) compile information on the distributions of likely VME taxa and habitats, as well as related environmental data; 5) develop predictive distribution models for VME indicator taxa and habitats; 6) compile known or likely fishing impacts; 7) produce a predicted VME naturalness distribution (areas of low cumulative impacts); 8) identify areas of higher value to user groups; 9) conduct management strategy evaluations to produce trade-off scenarios; 10) review and reiterate, until spatial management scenarios are developed that fulfil international obligations and regional conservation and management objectives. To date, regional progress has been piecemeal and incremental. The proposed 10-step framework combines these various experiences into a systematic approach. Highlights• The United Nations has passed resolutions to protect vulnerable marine ecosystems (VMEs);• Limited practical guidance exists on how to identify VMEs; • Approaches differ regionally, but none to date have been systematic; • Experiences and good practices are compiled here into a 10-step systematic approach;• Better integration across sectors will become increasingly necessary.

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The United Nations General Assembly resolution 61/105 calls for States to protect vulnerable marine ecosystems (VMEs), including cold-water corals, from destructive fishing practices in international waters. In response, the developing South Pacific Regional Fishery Management Organisation (SPRFMO) adopted interim measures requiring participating states to assess whether individual bottom fishing activities encounter VMEs, and to prevent significant adverse impacts on VMEs, including requiring vessels to cease fishing and move away from such areas. Criteria were developed to identify VMEs from trawl fishery bycatch data and other available scientific information. The criteria integrate information about the vulnerable taxa present, their relative abundance as bycatch, evidence from previous fishery interactions in the area, the degree of habitat isolation and an index of taxonomic distinctness. We also analysed observer data from previous fishing by New Zealand vessels to evaluate the use of bycatch thresholds to trigger a move-on rule in the SPRFMO area. A focus on documenting the distribution of vulnerable taxa and habitat associations through the most robust survey and habitat modelling means feasible will facilitate identifying representative spatial closures for long-term protection of VMEs.KEY WORDS: Vulnerable marine ecosystems · VME · Deep-sea coral · Benthic impacts · Move-on rule · High seas Resale or republication not permitted without written consent of the publisher Contribution to the Theme Section 'Conservation and management of deep-sea corals and coral reefs'

United Nations General Assembly Resolution 61/105 on sustainable fisheries (UNGA 2007) establishes three difficult questions for participants in high-seas bottom fisheries to answer: 1) Where are vulnerable marine systems (VMEs) likely to occur?; 2) What is the likelihood of fisheries interaction with these VMEs?; and 3) What might qualify as adequate conservation and management measures to prevent significant adverse impacts? This paper develops an approach to answering these questions for bottom trawling activities in the Convention Area of the South Pacific Regional Fisheries Management Organisation (SPRFMO) within a quantitative risk assessment and cost : benefit analysis framework. The predicted distribution of deep-sea corals from habitat suitability models is used to answer the first question. Distribution of historical bottom trawl effort is used to answer the second, with estimates of seabed areas swept by bottom trawlers being used to develop discounting factors for reduced biodiversity in previously fished areas. These are used in a quantitative ecological risk assessment approach to guide spatial protection planning to address the third question. The coral VME likelihood (average, discounted, predicted coral habitat suitability) of existing spatial closures implemented by New Zealand within the SPRFMO area is evaluated. Historical catch is used as a measure of cost to industry in a cost : benefit analysis of alternative spatial closure scenarios. Results indicate that current closures within the New Zealand SPRFMO area bottom trawl footprint are suboptimal for protection of VMEs. Examples of alternative trawl closure scenarios are provided to illustrate how the approach could be used to optimise protection of VMEs under chosen management objectives, balancing protection of VMEs against economic loss to commercial fishers from closure of historically fished areas.