Can ecosystem-based deep-sea fishing be sustained?

In this report, the main challenges of managing orange roughy fisheries are outlined, as well as lessons learned that could be applied in the future to fisheries for this species (and others like it) which in some cases may allow for an ecologically sustainable, albeit limited, commercial fishery. The term ‘sustainable’ or ‘sustainable fishery’ in this context is defined as a fishery which meets the objectives established by the UN General Assembly and through the UN FAO with regard to the management of deep-sea fisheries in areas beyond national jurisdiction. We consider whether any orange roughy fisheries currently do, or could, satisfy the UN and FAO guidelines, and what characteristics these fisheries might have. We consider the nature and impact of the fishery, the management framework, and the ability of science to inform management. Where one or more of these components are lacking, we conclude that a sustainable fishery is not possible. There is potential for a sustainable orange roughy fishery; most likely one that exploits spawning aggregations on flat ground, with accompanying monitoring using acoustic methods, and catch limits set using a demonstrable robust harvest rule. Such fisheries are likely to be very few in number, and provide catches that are much lower than historical, including recent, levels. SUSTAINABLE ORANGE ROUGHy FISHERIES The orange roughy (Hoplostethus atlanticus) has many biological characteristics (e.g. high longevity, late age of maturity, slow growth, predictable aggregation behaviour) that generally suggest it as a poor candidate for sustainable commercial exploitation (Branch 2001; Clark 2001; Francis & Clark 2005). It is perhaps the best studied example of what can go wrong when such a species is commercially exploited, as borne out historically in a string of boom-and-bust fisheries worldwide (e.g., Branch 2001; Clark 2001; Lack et al. 2003; Paya et al. 2005; Sissenwine & Mace 2007; ICES 2010). That said, in a few locations, such as Chatham Rise New Zealand, the sheer