The health of Antarctica’s Southern Ocean—remote and frigid waters housing biodiversity found nowhere else on Earth, including species uniquely adapted to its low temperatures—is critical to marine life and our global ocean.
These waters are home to Antarctic krill, tiny crustaceans that remove carbon from the atmosphere and serve as a critical food source for many vital endemic species, such as emperor, chinstrap, and Adélie penguins, and leopard and crabeater seals.1
Yet the health of our global ocean—including in the Antarctic—is in decline, largely because of human activities such as fishing, carbon emissions, pollution, etc., that are driving the collapse of fisheries, loss of biodiversity, and warming and acidification of seawater. There is growing scientific support for the benefits of restricting or eliminating human activity—especially industrial fishing—within systems of marine protected areas (MPAs) to allow fish populations to recover in key marine areas, creating a spillover effect that can sustain adjacent fisheries.
Networks of MPAs must be complemented by precautionary ecosystem-based fisheries management (EBFM) in adjacent waters. EBFM is a holistic approach that recognizes all the interactions within an ecosystem rather than considering a single species or issue in isolation. The goal of ecosystem-based management is to maintain healthy, productive, and resilient ecosystems, and weigh how a fished species interacts with other species and the effects of environmental change, pollution, and other stressors.2
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is the governing body responsible for protecting Southern Ocean wildlife and is composed of 26 member countries and the European Union. CCAMLR has the opportunity to make significant progress in the conservation of Antarctic marine life and turn this tide of human impacts by designating marine protected areas and advancing an EBFM plan for the krill fishery.3
Climate change impacts in Antarctica’s Southern Ocean
The Southern Ocean’s marine species are vulnerable to the changes happening from a warming climate because of their unique adaptations for surviving frigid temperatures. A 2019 report on polar regions from the International Panel on Climate Change stresses that climate scientists are concerned about changes to the Southern Ocean, including broad impacts on biodiversity, Antarctic sea ice loss, the southward contraction of habitat, and changes in the abundance of whales, birds, fish, and krill. The report also flagged additional climate impacts on krill, including changes to their growth and size, population declines due to ocean acidification, and the resulting negative impacts on krill predators and the krill fishery.4 The stressful impacts of climate change on krill and their predators near the Antarctic Peninsula are compounded by an increase in concentrated fishing within the same area.5
Research indicates that proposed MPAs in the Southern Ocean will help to provide ecosystem resilience as well as positive impacts on krill, their predators, and the krill fishery, even as the climate continues to change.6 Although addressing climate change is a global issue that will require global solutions, CCAMLR has at its disposal the ability to implement Southern Ocean MPAs and a strategic EBFM approach—precaution-based conservation measures that help to ensure that the krill-based ecosystem is protected from the overlapping impacts of climate change and fishing.
Supporting healthy fisheries
According to the U.N. Food and Agriculture Organization, more than a third of the fish stocks around the world are being overfished.7 Scientific evidence shows that, in addition to conserving and rebuilding habitats and biodiversity, fisheries can also benefit from MPAs and EBFM, which help ensure healthy populations of fished species, among other things.8 Through a concept known as the spillover effect, fished species within fully or strongly protected areas are more likely to supply adult and larval fish to areas outside of the MPAs, which then support healthy populations that can sustain or increase the catch of nearby fisheries.9
Connectivity bolsters protections: MPA networks and EBFM
The International Union for Conservation of Nature defines a network of MPAs as “a collection of individual marine protected areas operating cooperatively and synergistically, at various spatial scales, and with a range of protection levels, in order to fulfill ecological aims more effectively and comprehensively than individual sites could alone.”10
Marine scientists overwhelmingly agree that establishing networks of large MPAs complemented by an EBFM approach and good monitoring, control, and surveillance are essential for protecting the ocean’s biodiversity and making it more resilient to climate change. Greater resilience means that marine ecosystems can better resist and recover from shocks associated with changing ocean conditions and can help to maintain the vital services they provide to wildlife and people. Conservation networks also provide species with resilience to climate change by giving them places to feed and breed without human interference and creating protected pathways for species migrations and range shifts. This is especially true in the Southern Ocean, where protected waters can serve as natural laboratories for studying how intact marine ecosystems react to a warming and acidifying ocean.
Effective EBFM measures for waters adjacent to MPAs or as integral parts of MPA networks extend the benefits of MPAs beyond their borders. As part of its commitment to apply the precautionary principle, CCAMLR’s work on MPAs should be complemented with krill fisheries management measures that apply an EBFM approach that includes spreading out concentrated krill fishing to ensure that enough krill remains available for predators.
Protecting the Southern Ocean’s biodiversity safeguards ecosystem services for the planet
In Antarctica, MPAs and EBFM can help protect threatened biodiversity and improve chances for long-term ocean health and productivity, including many benefits for the global economy. An integrated network of Southern Ocean MPAs will lead to more resilient ecosystems and a healthy ocean for all of humanity, including generations to come. The Southern Ocean’s unique biodiversity provides essential ecosystem services to the entire planet and has until recently remained largely free of anthropogenic impacts.11
It is becoming increasingly clear to Antarctic scientists that the Southern Ocean plays an important role in the biological capture and sequestration of carbon.12 For example, Antarctic krill play a prominent role in the cycling of nutrients in the Southern Ocean through their large swarms, substantial biomass, daily vertical migrations through the water column and wide distribution. Antarctic krill influence both surface productivity (as primary prey for many species) and the increasingly important deep carbon sink of the Southern Ocean (through their dense fecal pellets that descend quickly to the deep seas).13
Over time, well-funded and fully protected MPAs result in more fish, bigger fish, and greater biodiversity. Research indicates that roughly 71% of MPAs have positively affected global fish populations.14 Southern Ocean MPAs can preserve the economic benefits of tourism as well as lead to economic growth through enhanced fisheries production. The Western Antarctic Peninsula provides vital habitats to some of the ocean’s most iconic species and, despite its remoteness, attracted more than 74,000 visitors in 2019-20.15 The Antarctic tourism industry has been steadily increasing since the early 1990s, and as other tourism hot spots have demonstrated, boosts in sustainable tourism can lead to a growth in scientific investments.16
In addition to supporting more productive fisheries and tourism, MPAs that protect Southern Ocean biodiversity also safeguard vital genetic resources such as enzymes from sponges used to cure cancers and other infections, vast quantities of Earth’s fresh water and air, global nutrient cycling, and Antarctica’s irreplaceable climate regulating abilities.
Through the spillover effect, Southern Ocean MPAs help support healthy Antarctic krill and toothfish fisheries and sustain viable fish populations for current and future generations. (See graphic.) Although research to quantify the immense value of the Southern Ocean remains ongoing, scientists know it is worth protecting now— both economically and environmentally.
The Southern Ocean is home to unique flora and fauna found no place else on Earth. Its icy habitats are essential to regulating the Earth’s climate and protecting Antarctic krill, which support the Antarctic marine food web.
Therefore, it is important that CCAMLR implement a precaution-based approach to the conservation of Antarctic marine living resources by accomplishing the following:
- Follow through on its commitment to establish a network of connected MPAs that are representative of the habitat diversity by designating the three current proposals in the Weddell Sea, the East Antarctic, and the Antarctic Peninsula.
- Establish scientifically supported and precautionary EBFM conservation measures that more effectively spread out catch and account for the needs of krill predators.
- E.L. Cavan et al., “The Importance of Antarctic Krill in Biogeochemical Cycles,” Nature Communications 10, no. 4742 (2019).
- National Oceanic and Atmospheric Administration, “Understanding Ecosystem-Based Fisheries Management,” accessed Jan. 6, 2023, https://www.fisheries.noaa.gov/insight/understanding-ecosystem-based-fisheries-management.
- B.C. O’Leary and C.M. Roberts, “The Structuring Role of Marine Life in Open Ocean Habitat: Importance to International Policy,” Frontiers in Marine Science (2017).
- M. Meredith et al., “Polar Regions,” in “IPCC Special Report on the Ocean and Cryosphere in a Changing Climate” (2019): 203-320.
- G.M. Watters, J.T. Hinke, and C.S. Reiss, “Long-Term Observations From Antarctica Demonstrate That Mismatched Scales of Fisheries Management and Predator-Prey Interaction Lead to Erroneous Conclusions About Precaution,” Scientific Reports 10, no. 1 (2020): 2314, https://doi.org/10.1038/s41598-020-59223-9.
- A. Dahood, K. de Mutsert, and G.M. Watters, “Evaluating Antarctic Marine Protected Area Scenarios Using a Dynamic Food Web Model,” Biological Conservation 251 (2020): 108766, https://www.sciencedirect.com/science/article/pii/S0006320720308247.
- U.N. Food and Agriculture Organization, “The State of World Fisheries and Aquaculture 2018: Meeting the Sustainable Development Goals” (2018), http://www.fao.org/state-of-fisheries-aquaculture.
- E. Klein and G.M. Watters, “What’s the Catch? Profiling the Benefits and Costs Associated With Marine Protected Areas and Displaced Fishing in the Scotia Sea,” PLOS ONE 15, no. 8 (2020).
- B.S. Halpern, S.E. Lester, and J.B. Kellner, “Spillover From Marine Reserves and the Replenishment of Fished Stocks,” Environmental Conservation 36 (2010): 268-276, https://doi.org/10.1017/S0376892910000032; H.B. Harrison et al., “Larval Export From Marine Reserves and the Recruitment Benefit for Fish and Fisheries,” Current Biology 22, no. 11 (2012): 1023-28, https://doi.org/10.1016/j. cub.2012.04.008; M. Di Lorenzo et al., “Assessing Spillover From Marine Protected Areas and Its Drivers: A Meta-Analytical Approach,” Fish and Fisheries 21, no. 5 (2020): 906-915, https://doi.org/10.1111/faf.12469; E. Sala et al., “Fish Banks: An Economic Model to Scale Marine Conservation,” Marine Policy 73 (2016): 154-161, https://doi.org/10.1016/j.marpol.2016.07.032; E. Sala and S. Giakoumi, “No-Take Marine Reserves Are the Most Effective Protected Areas in the Ocean,” ICES Journal of Marine Science 75, no. 3 (2017): 1166-8, https://doi.org/10.1093/icesjms/fsx059.
- International Union for Conservation of Nature, “Establishing Marine Protected Area Networks” (2008), https://www.iucn.org/content/establishing-marine-protected-area-networks.
- A.D. Rogers et al., “Antarctic Futures: An Assessment of Climate-Driven Changes in Ecosystem Structure, Function, and Service Provisioning in the Southern Ocean,” Annual Review of Marine Science 12, no. 7 (2020): 87-120, https://doi.org/10.1146/annurev-marine-010419-011028.
- N. Bax et al., “Perspective: Increasing Blue Carbon Around Antarctica Is an Ecosystem Service of Considerable Societal and Economic Value Worth Protecting,” Global Change Biology (2020): 1-8, https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.15392; D.K.A. Barnes, “Polar Zoobenthos Blue Carbon Storage Increases With Sea Ice Losses, Because Across-Shelf Growth Gains From Longer Algal Blooms Outweigh Ice Scour Mortality in the Shallows,” Global Change Biology 23, no. 12 (2017): 5083-91, https://doi.org/10.1111/gcb.13772.
- E.L. Cavan et al., “The Importance of Antarctic Krill in Biogeochemical Cycles,” Nature Communications 10, no. 4742 (2019), https://doi.org/10.1038/s41467-019-12668-7.
- D.A. Gill et al., “Capacity Shortfalls Hinder the Performance of Marine Protected Areas Globally,” Nature 543, no. 7467 (2017): 665-9, https://doi.org/10.1038/nature21708.
- International Association of Antarctica Tour Operators, “Data & Statistics” (2021), https://iaato.org/information-resources/data-statistics/.
- H.S.J. Cesar and P.J.H. van Beukering, “Economic Valuation of the Coral Reefs of Hawai’i,” Pacific Science 58, no. 2 (2004): 231-42, http://hdl.handle.net/10125/2723.
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