Ocean floor features such as seamounts are hotspots of biodiversity1. They trap plankton and tiny animals that are food for coral and fish, forming the base of an extensive food web. The physical shape of coral provides nursery habitat for fish. The benefits extend around the area, with higher populations of organisms including species of interest to fishing vessels being found in the water column over some seamounts. Hydrothermal vents, trenches and seeps host life rarely found elsewhere.

On land, it has become customary to protect highly biodiverse areas, for the direct benefits to nature and for the eventual economic return that protection brings. The same is not true of the global ocean – particularly the high seas. Even activities such as bottom-trawling have proven stubbornly hard to regulate.

While all of the threats pose hazards to ocean biodiversity on their own, there is growing evidence that together, their impact is much greater2. Overfishing reduces ecosystems’ resilience to climate change; acidification exacerbates the impacts of reduced oxygen levels. The long-term casualty is biodiversity. With carbon emissions steadfastly rising, measures to protect biodiversity through regulating fishing assume even greater importance because of the greater resilience they confer.

Human rights and security

The principles of high seas navigation enshrined in UNCLOS give ships, including fishing vessels, the right to travel virtually anywhere on the high seas. Modern equipment such as Automatic Identification Systems (AIS) or Vessel Monitoring Systems (VMS)3 can track and monitor ship movements. But most high seas fishing vessels do not always use these systems – nor do they carry a unique and unchangeable International Maritime Organization (IMO) number4.

This makes vessels owned and operated by unscrupulous parties useful to international criminal operations. A UN review in 20115 concluded that ‘fishing vessels are used for the purpose of smuggling of migrants, illicit traffic in drugs (primarily cocaine), illicit traffic in weapons, and acts of terrorism’. It also documented working conditions that amounted to forced labour: ‘fishers are held as de facto prisoners of the sea… a particularly disturbing facet of this form of exploitation is the frequency of child trafficking in the fishing industry’.

The report concluded that several issues contribute to these abuses and security concerns:

  • licensing systems for fishing vessels are opaque and vulnerable to corruption
  • the global fishing fleet has an excess of capacity in relation to fish stocks and quotas, producing a need for owners to seek other sources of income
  • there is a lack of surveillance on the high seas.

In coastal waters, for example around Somalia, overfishing is also cited as a contributor to piracy6, as foreign vessels have depleted fish stocks on which local people traditionally relied.


Fishing yields across the ocean are declining7, despite an increase in investment in terms of the number of fishing vessels8 and advanced technology. Simply, there are fewer and fewer fish to catch. Reducing fishing effort, allowing stocks to rebuild, and then setting sustainable catch levels would put about $50bn per year into the global economy9, with the costs of restraint paying for themselves in just 12 years10.

The overcapacity issue is stimulated by subsidies, which now amount to about $30bn per year11. Governments give subsidies with the intention of supporting livelihoods and securing fish supplies – but the long-term impact is exactly the reverse: overcapacity depletes stocks, leading to sub-optimal yields and financial returns. In most cases, subsidies are directed at large industrial operations – often to the detriment of small-scale artisanal fleets that could support more jobs and more sustainable fishing.

Illegal, unreported and unregulated (IUU) fishing is estimated to be worth $10-23bn per year12. That creates a direct loss to legal fleets, a reduction in tax revenues for governments, and destruction of the global resource.

Turtles are among marine life impacted by ‘ghost’ fishing nets (Greenpeace/Care/Marine Photobank)

“I was sold into slavery by brokers, who passed me from one hand to another. Eventually I was sold to a (Thai) fishing company… When I was on the boat, a Thai cook beat one of our Burmese guys with an iron bar in front of my eyes… the guy was hit at the back of his head and his brains spilled out. I grabbed him; he took an hour to die. The young guy took an hour to die.” Saing Winna, an escaped Burmese fishing crewman, in Tual, Indonesia: Environmental Justice Foundation report ‘All at Sea’, 201213

Conditions on board illegal fishing vessels can amount to slavery (Environmental Justice Foundation)