An Ecosystem Evaluation Framework for Global Seamount Conservation and Management

Abstract

In the last twenty years, several global targets for protection of marine biodiversity have been adopted but have failed. The Convention on Biological Diversity (CBD) aims at preserving 10% of all the marine biomes by 2020. For achieving this goal, ecologically or biologically significant areas (EBSA) have to be identified in all biogeographic regions. However, the methodologies for identifying the best suitable areas are still to be agreed. Here, we propose a framework for applying the CBD criteria to locate potential ecologically or biologically significant seamount areas based on the best information currently available. The framework combines the likelihood of a seamount constituting an EBSA and its level of human impact and can be used at global, regional and local scales. This methodology allows the classification of individual seamounts into four major portfolio conservation categories which can help optimize management efforts toward the protection of the most suitable areas. The framework was tested against 1000 dummy seamounts and satisfactorily assigned seamounts to proper EBSA and threats categories. Additionally, the framework was applied to eight case study seamounts that were included in three out of four portfolio categories: areas highly likely to be identified as EBSA with high degree of threat; areas highly likely to be EBSA with low degree of threat; and areas with a low likelihood of being EBSA with high degree of threat. This framework will allow managers to identify seamount EBSAs and to prioritize their policies in terms of protecting undisturbed areas, disturbed areas for recovery of habitats and species, or both based on their management objectives. It also identifies seamount EBSAs and threats considering different ecological groups in both pelagic and benthic communities. Therefore, this framework may represent an important tool to mitigate seamount biodiversity loss and to achieve the 2020 CBD goals.

Towed camera imagery and benthic sled catches provide different views of seamount benthic diversity

“…In practice, methods used in the deep sea to describe benthic diversity, and to underpin the frameworks used for policy setting and management, are typically not yet widely applied (e.g., Collins et al ), still developmental (Taranto et al ; Clark et al, ), or problematic (e.g., Auster et al ). While each application will have different demands, many will include measurements of diversity, or abundance, or both, and often in areas of conservation sensitivity (Collins et al ).…”

“…Anthropogenic impacts in the deep sea have historically often been concentrated on seamounts, e.g., the multiple detrimental impacts from bottom‐contact fishing (Althaus et al ; Williams et al a ), a pattern that may intensify with future mining on seamounts (Clark et al ; Schlacher et al ). Because human impacts also extend into high seas areas beyond national jurisdictions, their evaluation is now an issue of major conservation concern internationally; consistent and effective protocols are needed to identify deep‐sea areas in need of conservation intervention (Taranto et al ; Clark et al ).…”

Adding the Third Dimension to Marine Conservation

“…), such as fishing, drilling, and deep‐sea mining (Taranto et al . ). This is evident, for example, in the global scale depletion of some pelagic fisheries in recent decades (Juan‐Jordá et al .…”

“…Until the 1960s, human activity, exploitation of marine resources, and consequently marine conservation efforts, were focused on near-coast and shallow regions (Merrie et al 2014). However, the remote areas of the offshore open oceans and the deeper seas are no longer considered "virgin" frontier areas and are experiencing a dramatic intensification in the extent and intensity of human uses and threats to biodiversity natural ecosystems (Merrie et al 2014), such as fishing, drilling, and deep-sea mining (Taranto et al 2012). This is evident, for example, in the global scale depletion of some pelagic fisheries in recent decades (Juan-Jordá et al 2011), especially for large fish (Sibert et al 2006), accompanied by an increase in the average depth of trawling (50-100 m increase per decade; Glover & Smith 2003;Gordon 2001).…”

Seamounts on the High Seas Should Be Managed as Vulnerable Marine Ecosystems

“…We know little about patterns of reproduction and dispersal, genetic connectivity, functional role, and the direct and indirect responses of seamount species that could be triggered by their removal (e.g., reduction or local extinction of linked coral populations and populations of associated commensal species, reduced role of corals providing prey subsidies to mobile predators with bioenergetic effects on growth and reproduction). In fact, while seamount faunas have varying degrees of heterogeneity within and between seamounts (Kvile et al, 2014;Clark et al, 2015), the degree of uncertainty associated with attempts to extrapolate limited data in order to quantify vulnerability to human activities is sufficiently large (Taranto et al, 2012), suggesting the highest levels of precaution are necessary for management. While most RFMOs have designated closures around some seamounts, the footprint of fishing remains large and many seamounts remain vulnerable to fisheries that are extending their geographic range into deep water.…”