The policy relevance of Southern Ocean food web structure: Implications of food web change for fisheries, conservation and carbon sequestration. (May 2020)

• Record Type: Journal Article
• Authors: Trebilco, Rowan; Melbourne-Thomas, Jess; Constable, Andrew John
• Is Part Of: Marine policy. Volume 115(2020)
• Publication Date: 2020-05
• Subjects: Ecosystem impacts of climate change -- Ecosystem management -- Ecosystem status and trends -- Marine ecosystem assessment for the Southern Ocean -- Science-policy -- Southern Ocean ecosystems; Marine resources -- Economic aspects -- Periodicals; Fisheries -- Periodicals; Ressources marines -- Aspect économique -- Périodiques; Pêches -- Périodiques; Fisheries; Marine resources -- Economic aspects; Periodicals; 333.916405
• DOI: 10.1016/j.marpol.2020.103832
• Languages: English
• ISSNs: 0308-597X

Abstract

Abstract: Southern Ocean food webs provide ecosystem services with significant global value including carbon sequestration, fisheries and the existence of iconic wildlife. These services are underpinned by different energetic pathways including those dominated by Antarctic krill, fishes and squids, or gelatinous zooplankton (salps). Climate change is likely to impact Southern Ocean food webs by affecting their foundations — both primary producer communities and ice habitats. However, the implications of these changes for ecosystem services – including wildlife populations, fisheries and carbon sequestration – are unclear, as are the implications for policy and management. Here, we use a generalised representation of Southern Ocean food webs and qualitative network modelling to investigate the consequences of five simple but plausible scenarios of future change for ecosystem services and the conservation of important taxa: (i) a shift in primary producer communities with decreasing large diatoms and increasing small flagellates; (ii) increasing salps; (iii) increase (recovery) of the Great whales; and unregulated and unsustainable fisheries for (iv) krill or (v) toothfish. Strikingly, our results suggest that increases in salps might not have negative consequences for ecosystem services and could enhance carbon export potential. Simulated increases in unregulated krill and toothfish fisheries affect predatory wildlife and could also reduce carbon export potential. Our results emphasise the important policy implications of understanding the structure and change of whole food webs, and highlight that improved quantitative understanding and modelling of the relative importance of different energy pathways will be important for developing robust management responses to climate change impacts. Graphical abstract: Highlights: Southern Ocean food web structure and change have important policy implications. Increases in gelatinous zooplankton may enhance carbon sequestration and fisheries. Changing phytoplankton composition will likely be negative for krill. Uncontrolled IUU fishing will degrade ecosystems and could reduce carbon sequestration. Enhanced modelling capability for energy pathways will support ecosystem management.