Rebuilding marine life

Abstract

The UN Sustainable Development Goal 14 aims to "conserve and sustainably use the oceans, seas and marine resources for sustainable development". Achieving this goal will require rebuilding the marine life-support systems that deliver the many benefits society receives from a healthy ocean. In this Review we document the recovery of marine populations, habitats and ecosystems following past conservation interventions. Recovery rates across studies suggest that substantial recovery of the abundance, structure, and function of marine life could be achieved by 2050, should major pressures, including climate change, be mitigated. Rebuilding marine life represents a doable Grand Challenge for humanity, an ethical obligation, and a smart economic objective to achieve a sustainable future. The ability of the ocean to support human wellbeing is at a crossroads. The ocean currently contributes 2.5% of global GDP and provides employment to 1.5% of the global workforce 1 , with an estimated output of US$1.5 trillion in 2010, expected to double by 2030 1. And there is increased attention on the ocean as a source of food and water 2 , clean energy 1 , and as a means to mitigate climate change 3,4. At the same time, many marine species, habitats and ecosystems have suffered catastrophic declines 5-8 and climate change is further undermining ocean productivity and biodiversity 9-14 (Fig. 1). The conflict between growing human dependence on ocean resources and declining marine life under human pressures (Fig. 1) is focusing unprecedented attention on the connection between ocean conservation and human well-being 15. The UN Sustainable Development Goal 14 (SDG14 or "life below water") aims to "conserve and sustainably use the oceans, seas and marine resources for sustainable development" (https://sustainabledevelopment.un.org/sdg14). Achieving this goal will require rebuilding marine life, defined in the context of SDG14 as the life-support systems (populations, habitats, and ecosystems) that deliver the many benefits society receives from a healthy ocean 16,17. Here we show that, in addition to being a necessary goal, substantially rebuilding marine life within a human generation is largely achievable, if the required actions, prominently mitigating climate change, are deployed at scale. Slowing the decline of marine life and achieving net gains By the time the general public admired life below water through the "Undersea World of Jacques Cousteau" (1968-1976), the abundance of large marine animals was already greatly reduced 5-7,18. And the abundance of marine animals and habitats that support ecosystems services has shrunk to a fraction of what was in place when the first frameworks to conserve and sustain marine life were introduced in the 1980s (Fig. 1), to a fraction of pre-exploitation levels 5,6,19,20. Currently, at least one-third of fish stocks are overfished 21 , one-third to half of vulnerable marine habitats have been lost 8 , a substantial fraction of the coastal ocean suffers from pollution, eutrophication, oxygen d...

Functionally unique, specialised, and endangered (FUSE) species: towards integrated metrics for the conservation prioritisation toolbox

“…However, as they are not extinct and many show a strong capacity to recover given abatement of extreme exploitation pressure (Duarte et al 2020), there is still a chance to restore their populations and unique and specialised roles.…”

Commercial fishery disturbance of the global open-ocean carbon sink

“…The rebuilding of impacted ecosystems and stocks would help to reverse impacts on the carbon sink. This rebuilding is already an established fisheries management and sustainable development objective 27,38 but progress towards this goal is extremely limited and up to 63% of monitored stocks remain in need of rebuilding 27,39 .…”

“…Groundfish such as Atlantic cod and Alaska pollock (caught in fishing areas 27 and 61 respectively) are the next most important catch category after small pelagics (Supplementary Table 1), but their contribution to the carbon sink is also currently unknown. Groundfish fisheries could have the greatest impacts on the carbon sink through trophic cascades as described above in the Baltic Sea 26 and physical disturbance of the seabed 27,28 (Fig. 4).…”

Future carbon emissions from global mangrove forest loss

“…Overall our sensitivity analysis suggests that predictions on future emissions will be most sensitive to deforestation rates; thus, a research priority is developing scenarios for future mangrove loss that consider both climate and economic drivers of mangrove loss (Duarte et al, 2020;Schuerch et al, 2018). Our CO2 emission predictions could then be updated to account for changes in land-use trajectoriesand the resulting changes in losses and gainswhen higher-resolution global models of landscape change become available.…”