Life below water

  • Oceans face significant challenges from eutrophication, worsening acidification, declining fish stocks, rising temperatures and widespread pollution. All these factors destroy habitats, diminish biodiversity and threaten coastal communities and the health of marine ecosystems, vital to over 3 billion people.
  • Efforts to address these mounting concerns remain uneven. Key actions include implementing sustainable fishing practices, expanding marine protected areas to safeguard key biodiversity areas, increasing capacities to monitor ocean health and addressing the pollution that is choking waterways.
  • Comprehensive global action is under way , yet it must accelerate. Priorities include ensuring that the Agreement on Fisheries Subsidies enters into force as soon as possible; increasing participation in the Agreement on Port State Measures to combat illegal, unreported and unregulated fishing;

  • A group of bleached corals in a reef in Indonesia. Record high ocean temperatures have triggered a fourth global coral bleaching event.

     © Unsplash/Nico Smit

    adopting a global plastic pollution instrument; and ensuring that the Agreement on Marine Biodiversity of Areas Beyond National Jurisdiction enters into force as soon as possible to ensure the long-term health and sustainability of oceans.

    Overfishing, pollution, climate change and poor management drive continued declines in fish stocks

    The sustainability of global fishery resources declined from 90.0 per cent in 1974 to 64.6 per cent in 2019 and further to 62.3 per cent in 2021, due to overfishing, pollution, poor management and other factors. Fish stocks within biologically sustainable levels, however, comprised around 76.9 per cent of global marine fish landings in 2021. Averaging 80 million tons annually, global marine fish landings have remained relatively stable since 1995.

    Trends in 2021 for major fishing regions vary greatly, from 33 per cent to 84 per cent of fish stocks at sustainable levels (underfished and maximally sustainably fished). The Southeast Pacific had the highest percentage of overfished stocks at 66.7 per cent, followed by the Mediterranean and Black Sea at 62.5 per cent, the Northwest Pacific at 56 per cent and the Eastern Central Atlantic at 51.3 per cent. In contrast, the Eastern Central Pacific, Northeast Atlantic, Northeast Pacific and Southwest Pacific had the lowest proportions of overfished stocks, ranging from 16 to 24 per cent.

    Overfishing could harm biodiversity, ecosystems and fisheries production, and imposes adverse social and economic costs. Effective fisheries management can possibly reverse these effects (if they are driven by overfishing and not factors such as habitat degradation, pollution or climate change) and lead to optimal stock levels while supporting global food security and coastal communities. The ongoing albeit decelerated decline in biologically sustainable fish stocks worldwide underscores the need for enhanced regulatory frameworks and efficient monitoring systems.

    Proportion of fish stocks within biologically sustainable and biologically unsustainable levels, 1974-2021 (percentage)
    Note: Underfished and maximally sustainably fished stocks are considered within biologically sustainable levels. Overfished stocks are considered at biologically unsustainable levels.
    Proportion of fish stocks within biologically sustainable levels, by marine region, 2004 and 2021 (percentage)

    Sustainable fisheries' contribution to GDP declined worldwide yet several regions saw positive trends

    The value added of fisheries and aquaculture rose by 10 per cent from 2019 to 2021. The contribution of sustainable fisheries to GDP declined 5.4 per cent in 2021, however, mainly due to the expansion of other economic sectors and the declining sustainability of several fish stocks in some regions. This marks a second consecutive drop following a brief period of growth from 2015 to 2017. Recovery from COVID-19 disruptions has been challenging, with the industry facing volatile demand and rising costs.

    Several countries that depend heavily on fisheries for livelihoods and food security, however, have seen positive developments. In sub-Saharan Africa, the contribution of sustainable fisheries to GDP climbed from 0.38 per cent in 2019 to 0.42 per cent in 2021. Small island developing States have similarly shown promising growth, from 0.46 per cent of GDP in 2019 to 0.51 per cent in 2021. Pacific small island developing States, which rank among the countries most dependent on fisheries globally, increased their share from 1.54 per cent of GDP in 2019 to 1.63 per cent in 2021. This rise underscores the sector's potential to drive economic development. Sustaining economic dividends from fisheries, however, requires judicious fish stock management practices that prevent overexploitation and depletion.

    Sustainable fisheries as a proportion of GDP, 2015-2021 (percentage)
    *Excluding Australia and New Zealand.

    Global agreements could renew momentum to protect key biodiversity areas in the oceans

    As of May 2024, there are 18,200 marine protected areas and 199 other effective, area-based conservation measures1 covering over 29 million square kilometres or 8.12 per cent of the ocean. This represents a more than tenfold increase in marine protected area coverage since 2000, largely due to the establishment of very large areas exceeding 100,000 square kilometres. Progress has stalled since 2020, however. Reaching the 10 per cent SDG target by 2030 calls for effectively managing important sites covering an average additional 1.13 million square kilometers of ocean each year. Renewed momentum for marine conservation is expected from global agreements. The Kunming-Montreal Global Biodiversity Framework commits to establish protected areas to safeguard areas of particular importance for biodiversity, adding up to cover 30 per cent of oceans by 2030. Additionally, the Agreement on Marine Biodiversity of Areas Beyond National Jurisdiction aims to protect marine biodiversity in international waters and seabed. Adequate management of such protected areas will be crucial to realize conservation benefits.

    Marine designations should also be strategically located to safeguard key biodiversity areas. Since 2000, average protected area coverage of marine key biodiversity areas has nearly doubled, but growth has stagnated since 2015. From 2000 to 2015, Oceania (excluding Australia and New Zealand) saw a staggering 255 per cent increase in key biodiversity area coverage, followed by Northern Africa and Western Asia (128 per cent) and sub-Saharan Africa (86 per cent).

    Since 2015, sub-Saharan Africa has led with an 18 per cent increase, followed by Northern Africa and Western Asia (10 per cent). Less than 30 per cent of marine key biodiversity areas in Oceania (excluding Australia and New Zealand), Central and Southern Asia, and Northern Africa and Western Asia are protected, however, highlighting a critical need for action within the next six years.

    Mean proportion of each marine key biodiversity area covered by protected areas, 2000, 2015 and 2023 (percentage)
    *Excluding Australia and New Zealand.

    1 These measures provide sustained, positive conservation outcomes even if they are managed primarily for other purposes.

    Record high ocean temperatures have triggered a fourth global coral bleaching event

    Rising ocean temperatures are raising new concerns for coral reefs, which support a quarter of marine species, provide resources for hundreds of millions of people in coastal communities and generate trillions of dollars in revenue annually. According to the World Meteorological Organization, as of April 2024, sea surface temperatures had reached record highs for 13 consecutive months. In 2023, ocean heat content soared to its highest level in 65 years; over 90 per cent of the ocean experienced heatwave conditions at some point during the year. The National Oceanic and Atmospheric Administration confirms the world is currently experiencing its fourth global coral bleaching event, the second in a decade. Bleaching has been observed in 53 countries and territories, including throughout the tropics, the Great Barrier Reef, large parts of the South Pacific, and the Atlantic and Indian ocean basins.

    As oceans continue to warm amid rising global temperatures, the frequency and severity of coral bleaching will likely increase. The Intergovernmental Panel on Climate Change warns that up to 90 per cent of corals could be lost by 2050 at 1.5°C of warming and up to 99 per cent at 2°C. The survival of coral reefs is vital for ocean health and humanity's well-being.