Willem Visser, Sector Portfolio Manager, Impact and Emerging Markets at T. Rowe Price, has penned a warning to consumers and investors about overfishing ahead of World Ocean Day on 8 June.
On World Ocean Day, we often celebrate the beauty and bounty of our seas. But behind the shimmering surface lies a crisis that threatens not just marine life, but global food security, livelihoods, and climate resilience. The crisis is overfishing. And it’s accelerating.
In 2021, global fish production reached a record 182 million tonnes - split almost evenly between wild capture and aquaculture[1]. That might sound like a triumph of human ingenuity. But it’s a warning sign. One out of every three fish populations that are caught in the wild is being harvested faster than it can naturally replenish, meaning it is overfished. Nearly 60% are fished to their maximum sustainable limit. Only 7% remain underfished, a margin that’s shrinking fast.
The Pacific Ocean alone yielded 47 million tonnes of fish in 2021. The top 10 fishing nations - led by China, Indonesia, and Peru - accounted for 60% of global capture. But the most caught species weren’t destined for dinner plates. It was the Peruvian anchovy, used primarily to make fishmeal for farmed fish and livestock. In other words, we’re emptying the ocean to feed industrial farms.
Aquaculture, often hailed as a sustainable alternative, is a double-edged sword. It has grown nearly sevenfold since 1990, but many farmed fish are fed with wild-caught species. It can take several kilos of small fish to produce just one kilo of farmed salmon or tuna. This is not a solution, it’s a feedback loop of depletion.
And then there’s the invisible threat: illegal, unreported, and unregulated (IUU) fishing. It’s estimated that one in every five fish is caught outside the law. Small-scale fisheries, which account for 40% of the global catch and employ 90% of the world’s fishers, often lack the technology to track or report their activity. That makes regulation nearly impossible.
Climate change is compounding the damage. Rising ocean temperatures, acidification, and deoxygenation are pushing marine ecosystems to the brink. Fish stocks are migrating toward the poles or deeper waters. Some may adapt. Many won’t. The Intergovernmental Panel on Climate Change (IPCC) warns that the global fish catch could decline by up to 40% by 2050. Already, a third of shark and ray species are threatened with extinction, up from a quarter just a few years ago.
This isn’t just an ecological crisis. It’s a human one. Around 60 million people work in fisheries - most in small-scale operations. Indigenous communities, in particular, rely heavily on marine resources. In some coastal Indigenous populations, fish consumption is nearly four times the global average. For them, this is not just about food. It’s about culture, identity, and survival.
So, what can we do?
Sustainable investment in the ocean economy is not only possible; it’s increasingly essential. We must stop treating the ocean as an endless resource and start funding it like the fragile, life-sustaining system it truly is. This means investing in sustainable aquaculture practices that do not rely on wild fish for feed, thereby breaking the destructive cycle of depleting one species to farm another. It also requires expanding and enforcing marine protected areas, giving ecosystems the space and time they need to recover.
Real-time monitoring technologies, such as satellite tracking and Automatic Identification Systems (AIS), must be scaled up to improve transparency and accountability across global fisheries. And perhaps most critically, governments must strengthen the enforcement of fishing quotas and crack down on illegal, unreported, and unregulated fishing, which continues to undermine conservation efforts and economic stability alike.
Governments must also rise to the challenge. Stronger regulations, better data transparency, and rigorous enforcement of fishing quotas are all essential to curbing overexploitation. International cooperation is equally vital, particularly when it comes to addressing illegal fishing and protecting the high seas.
Ending overfishing isn’t just about saving fish. It’s about saving ourselves. Governments must act. Investors must act. And we, as consumers and citizens, must demand change. The outdated belief that profit must come at the planet’s expense is being overturned. Sustainability is no longer a moral luxury - it’s a financial necessity. The question isn’t whether we can afford to act. It’s whether we can afford not to.
By Willem Visser, Sector Portfolio Manager, Impact and Emerging Markets at T. Rowe Price
