The evolution of marine biomass: Past, present, and future of fish in the oceans

A bountiful ocean: The past

Until the mid-20th century, fishing in the oceans was mostly artisanal and sustainable. According to data from the Food and Agriculture Organization (FAO), before 1950, between 15 and 20 million tonnes of fish were caught annually. Marine populations were generally abundant, and ecosystems were balanced.

Early scientific records indicate that large cod stocks in the North Atlantic, for example, could reach densities of more than 5 tonnes per square kilometre. Whales, tuna, hake, and sardines were common across almost all oceans.

Boom and crisis: The present

The advancement of fishing technology and the expansion of industrial fishing have led to unprecedented levels of extraction. In 2022, the FAO estimated that global fish capture reached 92.2 million tonnes, with 87.5 million tonnes of aquaculture production (fish farming). Global demand for fish has increased by 122% since 1990, driven by population growth and rising consumption in Asia, Europe, and Latin America.

However, this growth has had consequences:

According to the latest State of World Fisheries and Aquaculture (SOFIA, 2022) report, 34.2% of global fish populations are overexploited, a significant increase from 10% in 1974.
Marine biodiversity has declined by 49% since 1970, according to WWF.
Populations of large predatory fish such as tuna, swordfish, and sharks have declined by up to 90% in some regions, according to Nature.

Additionally, ocean warming and acidification caused by excess CO₂ are altering critical habitats like coral reefs, which host about 25% of all marine life.

The future in 100 years

If current trends continue, scientists warn we could be on the brink of a marine ecological collapse.

A study published in Science (Worm et al., 2006) projected that, without proper fisheries management, by the year 2048, many commercial species could collapse functionally, meaning a reduction of more than 90% of their original biomass.

Looking ahead to 2125, several scenarios are being considered:

Scenario of inaction: If no conservation policies are implemented, models predict a loss of 70-80% of commercial marine biomass. This would compromise the food security of more than 3 billion people who depend on fish as a primary protein source.
Sustainability scenario: If fishing zones are regulated, marine reserves are established, and subsidies for destructive industrial fishing are reduced, models from the University of California show that fish populations could recover to 90% of their maximum sustainable yield within 30 years.

Human consumption and pressure on the oceans

Global per capita fish consumption has increased from 9 kg per person per year in 1961 to more than 20.5 kg in 2021, according to the FAO. Fish currently accounts for 17% of global animal protein intake and more than 50% in coastal countries in Southeast Asia and West Africa.

The growing demand has led to unsustainable practices such as bottom trawling, illegal, unreported, and unregulated (IUU) fishing, and overfishing of juveniles, which prevents species from recovering.

Solutions and pathways to sustainability

Despite the challenges, viable and scientifically supported solutions exist. Several organisations have successfully led initiatives that contribute to the preservation of marine life:

Marine Stewardship Council (MSC): A global nonprofit that promotes sustainable fishing practices. The MSC certification has been awarded to over 450 fisheries globally, representing over 10% of global wild fish catch, helping to ensure sustainable practices.
The Nature Conservancy (TNC): Through its “Healthy Oceans, Healthy People” programme, TNC has worked to protect marine habitats and has helped establish 30 marine protected areas around the world, safeguarding over 1.4 million square kilometres of ocean.
WWF's Smart Fishing Initiative: This initiative focuses on reducing the impact of overfishing and helping companies and fisheries make more sustainable choices. WWF has facilitated the protection of more than 10 million square kilometres of ocean under its conservation programmes.
Fishery Improvement Projects (FIPs): Initiated by organisations such as Sustainable Fisheries UW, these projects work directly with fisheries to implement sustainable management practices, leading to measurable improvements in fish stock recovery.
Seacology: A non-profit dedicated to protecting ecosystems, Seacology has funded over 150 conservation projects across 46 countries, working with communities to establish protected marine areas and sustainable fishery management systems.
Oceana: A global organisation focused on policy change and advocacy, Oceana has successfully secured commitments from governments to protect millions of square miles of ocean from overfishing and habitat destruction.

The ocean has been for centuries a natural pantry that feeds millions of people. Today, it faces its greatest ecological crisis due to overexploitation and climate change. Science is clear: we are still in time to reverse the situation, but actions must be urgent, coordinated, and sustained.

Ensuring a future with oceans teeming with life is possible, but it depends on bold political decisions, international cooperation, and a more aware global citizenry regarding the real value of our seas.