Connectivity of the High Seas to Coastal Waters

Date: 21st May 2021

Authors: Olivia Livingstone and John Paul Jose

A fisherman who builds his life around the Ocean, a community whose economy is supported by the Ocean, a beach lover, and you, reading this blog, because of your connection to the Ocean —or your love for reading blogs, are all inextricably linked to the high seas. And this is exactly what we are exploring here, the major links that coastal waters, coastal communities, and humanity share with areas beyond national jurisdiction (ABNJ).

Liberia, ©Olivia P. Livingstone

Areas beyond national jurisdiction, commonly called the high seas, is the area of the ocean beyond the 200 nautical miles from shore that cover nearly half of the Earth’s surface and represent 95% of Earth’s occupied habitats.  This area is richly endowed with biodiversity, both discovered and unknown, and has a strong connection to coastal waters. 

The connectivity of the high seas to coastal waters has been scientifically proven, as a growing body of literature and evidence suggests that both are tightly linked via two processes: ecological connectivity and ocean circulation connectivity, each exposing ecosystems of coastal waters to the downstream influence of activities in ABNJ (i.e. It has been shown that overfishing in the ABNJ can affect productivity and fishing opportunities in coastal waters).

Despite the growing evidence, there is still a disconnect between the management of the high seas and coastal waters due to coastal states prioritising coastal waters and a broken and highly fragmented regime governing ABNJ. As a consequence,  the effective, precautionary, and equitable management of ABNJ and its ecosystem services are neglected. Recognizing the connectedness of ABNJ and coastal waters is the first step towards better ocean management, leading to healthier ocean ecosystems and species, with direct and positive impacts on coastal communities.  

ABNJ provides critical ecosystem services, especially to coastal communities, that rely on marine resources for their food and livelihoods. The types of ecosystem services connecting ABNJ and coastal waters include (i) provisioning services (i.e. seafood, mineral, genetic, medicinal and ornamental resources); (ii) regulating services (i.e. air purification, climate regulation, biological control); and, (iii). cultural services (i.e. recreation and leisure, aesthetic, cultural, spiritual and historical).

Provisioning Services:

Kerala, India ©johnpauljos

Millions of people living in coastal areas of developing countries in general, and the Least Developed Countries (LDCs) in particular, rely heavily on marine and coastal resources for their livelihoods. A large number of commercially and culturally important migratory species straddle both the coastal zone and ABNJ, with the latter providing a critical lifecycle maintenance service to the former.  For example, the deterioration of ecosystems and habitat used by migratory species in ABNJ, which have high economic and cultural values for coastal communities, may disrupt the distribution of species by forcing them to travel longer distances to find alternative habitats, directly impacting species that coastal communities rely upon. Similarly, the disturbance of areas in ABNJ that are key spawning or nursery areas for the juvenile life stages of fish species would directly impact fish stocks in coastal areas connected via the ocean circulation of larvae.  

Regulating Services:

Carbon sequestration by the high seas indirectly impacts the coastal zone by acting to decrease climate warming, sea-level rise and ocean acidification, and in return, safeguarding habitats and species. This service provided by the high seas plays a major role in mitigating and combating the global climate crisis.

Cultural services: 

The Ocean has substantially held and still holds cultural significance for traditional coastal communities, as the prevailing mode of subsistence in these communities is fishing. As culture is organized as a system, external influences such as the depletion of fish stocks due to poor management in the high seas will bring about far-reaching impacts and repercussions for coastal communities. For example, if a key fish stock collapses that has long been the mainstay of a small-scale fishing community’s subsistence system due to poor management in ABNJ, it will force them to find a new source of food or revenue which may compel the community to target new species. In turn, this may require the community to learn how to utilize new and unfamiliar fishing methods and technologies. The utilization of new methods and technologies may then require changes in how the fishing effort is organized, prompting important changes in community social organization and patterns of interpersonal relations. The collapsed fish stock may also have had great symbolic importance in the community’s traditions, mythology, religion, and cultural identity, leaving those culturally significant components severely impoverished and incapable of being quickly revitalized. 

In addition, it is not just fundamental for coastal communities to remember the connectedness of coastal areas to ABNJ and act accordingly, but also that the wellbeing of vulnerable coastal communities is considered in the management of activities in ABNJ, as they can have serious repercussions for their livelihoods and wellbeing. For example, some of the most ABNJ-connected Least Developed Countries, such as Kiribati in the Pacific Ocean; Tanzania and Somalia in the Indian Ocean; and Liberia in the Atlantic Ocean are already facing, or may soon be exposed to, several significant challenges arising from pollution, overfishing, mining, and geoengineering experiments in the ABNJ. The impacts of these activities in ABNJ will be felt by coastal communities dependent on marine resources for sustenance and income.

The connectedness and services provided by the high seas deliver substantial revenue for LDCs.  For example, in Liberia ocean resources can be used to support entire communities and villages, fund the operation of national governments, service international debt or pay to import food for domestic consumption, thus contributing to national food security and diversification of diets. 

In the wake of  COVID and the economic and environmental crises these countries are battling, failure to protect the high seas and, consequently, the ecosystems and communities that rely on them, have the potential to threaten food security and degrade their already bad economic conditions. 

Goa, India ©johnpauljos

This is why it is important to view the high seas as not just a singular distant entity. The high seas are an integral part of the planet, as important as land and deeply linked to coastal waters and humankind. Therefore, the high seas need to be protected. A new high seas treaty being negotiated at the United Nations can help with this by transforming the way we manage and govern biodiversity in ABNJ and by establishing a mechanism to create marine protected areas on the high seas. The future of the High Seas and its connectivity to coastal communities depend on the success of the new high seas treaty and the political will and ambition of world leaders to change the status quo of high seas governance. Let us act now!


Dunn, D., et al. 2019. The importance of migratory connectivity for global ocean policy. Proc. of the R. Soc. Biological Sciences.


McGoodwin, J.R. 2001. Understanding the Cultures of Fishing Communities: A Key to Fisheries Management and Food Security. FAO, Rome. 

Popova, E., et al. 2019. Ecological connectivity between the areas beyond national jurisdiction and coastal waters: Safeguarding interests of coastal communities in developing countries. Marine Policy, 104.

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