Overfishing is unsustainable fishing—harvesting fish so aggressively that natural fish stocks cannot fully replenish themselves. Fish become fewer and smaller, and we risk harvesting them to extinction.
One way we know is that, despite having a greater capacity to catch fish than at any other time in human history, the total mass of fish that we catch is decreasing. Based on aggregated catch reports, Dr. Pauly estimates that the total mass of fish caught globally peaked in 1996, while the total catch in the North Atlantic peaked in 1975.
According to 2023 Tyler Prize Laureate Daniel Pauly, a good baseline for defining healthy fish stocks would be those available in 1950. At this time, fish stocks had recently enjoyed a break from intense fishing due to World War II, and heavy industrial fishing had not yet penetrated all the Earth’s oceans.
The “high seas” portions of the ocean that are outside any nation’s territorial control. Territorial waters called exclusive economic zones (EEZs) give way to the high seas 200 nautical miles off a nation’s coastline. The high seas comprise about 59% of Earth’s oceans.
Daniel Pauly, 2018
Because the high seas are so far away from the coast, and fish are so widely scattered and hard to find, only large ships with specialized support fleets are able to successfully fish there. Six countries - China, Taiwan, Japan, Indonesia, Spain, and South Korea - account for 80% of all high seas fishing (2016), taking much more than their fair share!
Banning fishing on the high seas would essentially transform 59% of Earth’s oceans into a vast marine reserve. Marine reserves give fish a safe place to grow and reproduce. Existing marine reserves have shown that protected fish populations grow so abundantly within the reserve that they spill over into unprotected waters, at which point these large, healthy fish are available for harvest. Fisheries researchers expect that protecting the high seas would have a similar global effect. Game fish would grow large and abundant in the protected high seas, and then they would migrate into territorially controlled waters where they would be available to catch.
Daniel Pauly, 2018
Incredibly, no. Tyler Laureate U. Rashid Sumaila has shown that the spillover effect would probably be large enough to increase the total global catch. If catch levels were to increase just 18% in territorial waters after a high seas ban, that territorial increase would result in a net gain in the quantity of fish taken globally. And 18% is a conservative forecast of the catch increase; a prominent model forecasts that banning fishing on the high seas would increase the catch in territorial waters between 10% to 70%, with the most likely scenario being an increase of more than 30% globally.
It may seem counterintuitive that fishing in fewer places would lead to more fish. But remember that fish stocks are extremely low now, after being overfished for so long. A high seas fishing ban will allow fish populations in the high seas to rebuild, acting like a global fish reserve. That large breeding population will then spill over into coastal areas - where they can be caught without overfishing!
There would be no appreciable reduction in the variety of gamefish available after a high seas ban. Dr. Sumaila analysis included 1,406 varieties of fish, and of those, only 19 varieties were available exclusively on the high seas. The remaining 1,387 varieties would remain available for harvest.
Generally, no. Most countries don’t even fish the high seas. In fact, smaller, poorer nations would benefit enormously from a high seas fishing ban. Dr. Sumaila estimates that a high seas ban would bring a 50% reduction in measures of inequality with respect to the distribution of fisheries.
Currently, a handful of wealthy nations with access to large, industrial fishing operations exploit gamefish on the high seas before they have a chance to migrate into territorial waters. A high seas fishing ban would ultimately put substantially more fish into the territorial waters of most small and developing coastal nations.
None of us can do it individually. Because the high seas are not owned or controlled by any single entity, it will take an international effort. But as Dr. Pauly points out, we’ve done it before, and we can do it again. Exclusive Economic Zones (EEZs) were once considered impractical, but the nations of the world wrote them into international maritime law. Today, EEZs are normal, widely accepted boundaries.
To do your part, consider joining a conservation group that advocates for the high seas, and remember to share information about the benefits of a high seas ban with all your friends.