Conserving High Seas Biodiversity

The range of cannon balls shot from land was the 17th Century definition of the "high seas". -- if they couldn't reach you, then you were there. Now the term is defined by Article 86 of the United Nations Convention on the Law of the Sea (UNCLOS): the high seas include "all parts of the sea that are not included in the exclusive economic zone, in the territorial sea or in the internal waters of a State, or in the archipelagic waters of an archipelagic State." This means that the high seas are more than 200 nautical miles beyond the coastal baselines of any country and beyond national exclusive economic zones (EEZs). They encompass the water and the seabed beneath, unless the continental shelf of a nation extends out more than 200 nautical miles.

The high seas cover approximately half the Earth and include a wealth of geology and biology. Beneath the surface lie trenches, canyons, mountains - including what some consider the tallest mountain in the world, Mauna Kea in Hawaii, rising over 10,000 meters from the sea floor. They include erupting volcanoes, thermal springs and cold seeps, vast plains of silt, and expanses of hard, mineral-laden floor. The high seas also harbor diverse and abundant life. Some animal species move great distances through or over them - whales, elephant seals, tunas, great white sharks, eels, albatross, sooty terns, and many more. Plankton, animal and plant, congest its upper levels in life and, in death, rain on the seabed below. Its waters and seabed harbor fish and invertebrate animals of many stripes - including squid, octopus, clams, worms, crustaceans, jellyfish, cold-water corals, and sponges. Microbes make it a living soup, with bacteria that feed on inorganic chemicals and can live where the temperature is 110 degrees Centigrade. Albatross and shearwaters dive below its surface for food while other birds, preferring not to get wet, snatch what they can at the surface.

The high seas are a place full of life, but that life is threatened. Greenhouse gases top other concerns, mostly carbon dioxide from fossil fuels that are warming and acidifying the seas. The evident solution is to reduce emissions from these mostly land-based sources, but that's not currently happening. Fertilizers and other chemicals run-off into coastal waters and affect seas further out. Marine debris, from activity on land and sea concentrates in vast gyres and entangles sea life.

Fishing, however, is the primary threat to life from activities conducted on the high seas. Its history is ‘anything goes’. "Freedom of the high seas" -- including "freedom of fishing"-- is enshrined in UNCLOS and customary international law. Many individual nations do little to regulate their own fishermen beyond the EEZ. Furthermore, many regional and subregional fisheries organizations have jurisdiction on the high seas, and their number and complexity confuses management. In consequence, high seas fishing is often excessive, illegal, unreported, unregulated, and done with destructive practices such as dragging nets over bottom habitats. It's been detrimental to whales, sharks, tunas, and many other target and non-target species. Commercial whaling knocked blue whales - the planet's largest animal - to a fraction of their original populations, and since whaling stopped for them any recovery has been slow; Blue fin tunas, prized for their sushi, have plummeted in the Atlantic and Mediterranean to the point where survival is questionable; The Great White Shark is now vulnerable to extinction; Long-lived, slow-reproducing Orange Roughy have been depleted by fishing on the sea mounts where they live in the South Pacific, and the bottom-trawling that catches them is destroying habitat for all the species living on those mounts.

Fortunately, UNCLOS and other international agreements authorize the actions needed to conserve highs seas life. Monitoring and enforcement remain a problem, with limited resources hampering efforts by nations that intend to comply, and flags of convenience from non-complying nations facilitating overfishing. Another fundamental problem, addressed below, is lack of clarity in conservation standards. Better guidance is needed, and a clear, authoritative voice is needed to be the steward of that guidance.

The principal global agreements regulating high seas fishing are UNCLOS and the 1995 "Agreement for the Implementation of the Provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 Relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks", which is sometimes referred to as the UN Fish Stocks Agreement and sometimes just UN Fishing Agreement (UNFA).

Article 119.1 of UNCLOS addresses conservation of the living resources of the high seas, and provides: "In determining the allowable catch and establishing other conservation measures for the living resources in the high seas, States shall:

  • take measures which are designed, on the best scientific evidence available to the States concerned, to maintain or restore populations of harvested species at levels which can produce the maximum sustainable yield, as qualified by relevant environmental and economic factors, including the special requirements of developing States, and taking into account fishing patterns, the interdependence of stocks and any generally recommended international minimum standards, whether subregional, regional or global;


  • take into consideration the effects on species associated with or dependent upon harvested species with a view to maintaining or restoring populations of such associated or dependent species above levels at which their reproduction may become seriously threatened."

UNCLOS's conservation provisions address all harvested species, but UNFA's reach is more complicated. The harvested species addressed are limited to "straddling" and "highly migratory" fish stocks. Straddling fish stocks are those whose ranges include more than one EEZ or include the high seas and at least one EEZ. Highly migratory fish stocks move long distances and cross more than one EEZ or cross the high seas and at least one EEZ. Said differently, these stocks are not restricted to the EEZ and interests of a single nation. If a fish stock is neither straddling nor highly migratory, then its harvest is not regulated by UNFA. Most high seas fisheries currently are limited to straddling or highly migratory stocks, but there are exceptions, such as stocks of the Orange Roughy in the South Pacific. A further complexity, adding to UNFA's scope, is that the agreement defines "fish" to include not just fish as most know them (typically vertebrates with gills and fins) but also non-sedentary mollusks and crustaceans. Sedentary species are "organisms which, at the harvestable stage, either are immobile on or under the seabed or are unable to move except in constant physical contact with the seabed or the subsoil." Hence UNFA covers harvest of organisms like squid and krill that swim, provided that they straddle or are highly migratory, but does not cover clams, hard-shell snails, barnacles, tubeworms, or seabed microbes that are cemented to surfaces or embedded in them.

UNFA's conservation policies are found in Articles 5, 6 and Annex II of the agreement. Article 5 provides "General Principles," and restates almost verbatim the text of Article 119.1(a) and (b) of UNCLOS. These provisions require measures to keep populations at levels that will provide "maximum sustainable yield" (MSY). The premise of MSY is that populations will, to a point, yield more harvest as fishing reduces numbers below the unexploited levels where environmental factors such as limited food hold numbers in check -- where populations are at the "carrying capacity" of the environment. If food is the limiting factor, for example, populations somewhat reduced by fishing will have more food to eat and the fish may reproduce faster, grow more rapidly, and "yield" more harvest. But MSY has limits. Over-fishing to extinction would obviously end yield, and as populations shrink in size there is a point, even if the populations are healthy and reproducing well, where further reduction in population size will yield less. The population at the point just before yield decreases is the level historically chosen for MSY, with fishing theoretically regulated to maintain that size.

In the past half century, MSY has been qualified by recognition that fish and other organisms have behaviors and ecologies that fishing can disrupt and lessen yield. Biological diversity and ecosystem health are now also accepted goals in addition to yield of harvested species. UNCLOS and the UNFA accommodate this more recent thinking. In both agreements, as cited above, the objective of MSY is qualified by "relevant environmental and economic factors, including the special requirements of developing States, and taking into account fishing patterns, the interdependence of stocks and any generally recommended international minimum standards, whether subregional, regional or global . . ." and by the need to prevent the "reproduction" of "associated or dependent" non-target species from being "seriously threatened." No limits are placed on the taxonomic status or mobility of these non-target species, nor are relevant environmental factors defined. One might wish for clearer language, but this agreement text provides the basis for high seas fishing regulation that is more protective than MSY alone would provide. The "special requirements of developing States" are presumably economic rather than environmental, but this provision should not be read to allow more exploitative practices than would otherwise be the case. It is better read to mean that developing nations may require financial assistance or preferences of some kind.

Article 5 of UNFA also contains provisions not found in UNCLOS, but that are consistent with it and support a higher standard for conservation than maximum sustainable yield. In particular, Article 5(a) of UNFA calls on parties to adopt measures to ensure "long-term" stability of stocks and to promote "optimum" utilization. The term "optimum" has been used in regulatory policy for harvested populations in the concept of "optimum sustainable population" (OSP), and refers to populations that may be managed for less harvest than MSY. For example, OSP was defined for marine mammals under U.S. law as a range of population sizes between the carrying capacity of the environment for a stock on the high side, and MSY on the low. The same concept was applied to populations of threatened species by the U.S. Scientific Authority under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) when that agreement was first implemented.

Article 5 (g) of UNFA provides that its parties "shall . . . protect biodiversity in the marine environment . . ." This provision is a broad mandate. The term biodiversity is not defined in the UNFA or UNCLOS but is defined - as "biological diversity" - in the 1992 global Convention on Biological Diversity (CBD), as follows:

"the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems. "

The key word in this definition is "variability," which all the other words qualify. The CBD definition includes variability between and within species and variability of ecosystems. Biological diversity is higher when then are more species, more ecosystems, more genetic variation within species, and a more distributed representation of all these things rather than having them clumped in a few places. But variability isn't everything, and the term biological diversity or biodiversity has been used primarily by the CBD parties and others as a reference to the richness of wild living nature in healthy ecosystems.

The CBD parties have issued various statements on what is needed for marine biodiversity conservation. These generally focus on the need to consider how fishing and other uses impact the ecosystems involved, not just the target species. Furthermore, in October 2010, the CBD adopted a target that "By 2020, at least . . . 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved . . ." Discussions leading up to these targets make clear that the parties contemplated parks, refuges and marine protected areas with significant restrictions on extractive uses, as in the national parks, wildlife refuges, and national monuments of the United States. International bodies other than the CBD have also advanced ecosystem conservation and measures beyond the simple population models of MYS. These include the Food and Agriculture Organization (FAO) and the UN General Assembly, recently in A/RES/65/38 adopted on December 7, 2010.

A mix of two models is required to implement the "ecosystem approach" advanced by the UN General Assembly, CBD and FAO for conserving biological diversity. The first model references the "original" features undisturbed by humankind, and the second references features exhibited when the objective is maximum sustainable yield, or MSY, with environmental qualifications. Together, the original condition and the condition of qualified MSY provide a vision and framework to meet the conservation needs of high seas ecosystems and the legal requirements of UNCLOS and UNFA.

These models can be mixed in two ways on the high seas. One is geographic - to establish marine protected areas (MPAs) closed to fishing and to establish other areas where sustainable fishing is authorized and facilitated. The alternative is to promulgate fisheries management regimes whose objectives are somewhere in-between no ecosystem impact and maintenance of stocks at MSY. This approach is also supported by Article 6 of UNFA, which articulates in detail a "precautionary principle" for regulation of fisheries. This principle now appears in various international regimes and largely speaks for itself. When in doubt, take less rather than more.

The geographic and regime-based mix of these two models should be the guiding policy for conservation of biological diversity in the high seas, including fisheries regulated under UNCLOS, UNFA, and the numerous regional and subregional fisheries organizations and arrangements. It is the grand compromise long practiced on public lands (and some waters) in many nations, including the United States. Thousands of areas in the U.S. considered most important for biodiversity have been designated as parks, refuges, and monuments and protected to keep them undisturbed. Many other areas including national forests and Bureau of Land Management units are managed for sustained use that is also protective of ecosystem values. The high seas are a global public area - deemed in UNCLOS to be not subject to the sovereignty of any state - and the same rationales and experiences that have led to the mix of these two models in national conservation recommends the same approach for the high seas. But if that can be agreed, a question still remains: who will refine, articulate and interpret the requirements for conserving biodiversity on the high seas and how will that guidance be incorporated into the fishery operations overseen by the many organizations involved?

A step forward in answering this question would be for the United Nations General Assembly to adopt a resolution that would:

  • Charge a new or existing UN committee (Committee) with developing and interpreting guidance for conserving biological diversity in high seas fishing.


  • Support an approach that embraces a mix of marine protected areas and regulated fisheries, and conservation objectives that range from preserving ecosystems undisturbed to providing maximum sustainable yield, qualified by considerations of ecosystem health.


  • Note the current efforts to identify particularly important or vulnerable areas in the high seas warranting protection, as well as the extensive work done to specify needs and appropriate practices for sustainable, ecosystem-sensitive, fishing.


  • Request that all UN members take steps to have the regional or subregional fisheries organizations in which they participate and their own flag vessels use the guidance articulated by the Committee.


  • Ask the Committee to meet in conjunction with meetings of other, existing efforts to further implementation of UNCLOS and UNFA. These include a UN informal consultative process on oceans and law of the sea that feeds into an annual review by the UN General Assembly, as well as an "Ad Hoc Open-ended Informal Working Group" to study issues relating to the conservation and sustainable use of marine biological diversity beyond areas of national jurisdiction. The UN also has a standing Subcommittee on Ocean and Coastal Areas and a network referred to as "UN-Ocean."

The way in which the Committee proposed here would meet and the name it would be given, are issues best left to UN staff and representatives. However the Committee would be advised to carryout most of its work over the Internet, to save time, expense, and environmental impact, and to encourage brevity and specificity in work products.

This is a modest proposal to solve a vexing problem. An alternative approach could be a high seas fisheries regulatory authority complementing the International Seabed Authority. But such an alternative approach would almost certainly invoke passionate opposition or non-participation from the nations that have made commitments and investments in regional and subregional organizations and arrangements. Another alternative would be to seek ways forward in forums other than the United Nations, such as the G-20, as now being done in climate change discussions. But fishing on the high sea, with flags of convenience available to any nation, does not lend itself to management by a subset of nations. This proposal for the UN General Assembly could be implemented without amending agreements or altering the operational roles of existing fisheries organizations. What it could do, however, is for the first time provide a clear and authoritative voice on what these organizations and nations should do to conserve high seas biological diversity.