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2014 High Seas Regional Assessment

The High Seas are defined as all marine waters outside of the Exclusive Economic Zones (EEZs) of coastal countries and their territories.  EEZs generally extend out to 200 nm from the coast; all waters beyond this point are the ‘High Seas’.  These waters comprise of 64 percent of the ocean’s surface and 95 percent of its volume. They are also referred to as International Waters and Areas Beyond National Jurisdiction (ABNJ), because no country owns them and they can only be regulated by international agreements. 

As portions of all oceans make up the High Seas, the Ocean Health Index (Index) used subdivisions created by the UN Food and Agriculture Organization (FAO) to create the High Seas assessment. 19 of these subdivisions include marine waters. Statistical area 37, the Mediterranean Sea, was excluded because EEZs of its bordering countries cover its entire area so there is no High Seas component. Areas number 58, 88 and 48 were analyzed separately as part of the 2014 Antarctic analysis. International waters of the remaining 15 statistical areas were used for this analysis.   

The Index assessed the health of the High Seas across three goals: Food Provision, Sense of Place and Biodiversity. Other goals normally assessed, such as Mariculture, Natural (Non-Food) Products, Opportunities for Artisanal Fishing and Coastal Protection, do not occur in the High Seas and cannot be reflected. Two other goals, Tourism & Recreation and Livelihoods & Economies occur in passing, when cruise ships or merchant ships transit the High Seas, but their benefits only accrue where trips originate and visit. Therefore, these two goals are not evaluated for the open ocean itself but are accounted for in the coastal countries or territories where the activities take place. 

The High Seas also provide other important general benefits, such as climate regulation and oxygen production by plant plankton but the Index does not assess them.


Through the above techniques, the High Seas regional assessment calculated the following average scores (all on a scale of 0 to 100):

  • High Seas overall average: 67 
  • Food Provision (Fisheries): 45
  • Sense of Place (Iconic Species): 75
  • Biodiversity (Species): 80
The Western Indian Ocean and East Central Atlantic Ocean had the highest overall scores (79).  The Northwestern Pacific Ocean had the lowest score (53). The Arctic Sea scored lowest in both Sense of Place (Iconic Species) and Biodiversity (Species).    

The Food Provision goal is represented by wild caught Fisheries, since High Seas has no mariculture at present.  Scores are based on a new approach to assessing food provision from wild caught fisheries that estimates population biomass relative to the biomass that can deliver maximum sustainable yield (B/BMSY) for each landed stock. Scores also incorporate factors such as quality of fisheries governance, accuracy in identification of fish caught, resilience of stocks and population biomass in comparison to maximum sustainable yield.

The Eastern Central Atlantic Ocean led in Fisheries, scoring 81 out of 100, followed by the Western Indian Ocean (80). Several very productive species contributed to these scores and fish stock biomass appeared to be closer to the target of being within 5% of the biomass that produces maximum sustainable yield. The Northwestern Pacific Ocean had the lowest score (7) driven down by the low Status component, showing that it is farthest from meeting the reference point of having the Biomass of stocks within 5% of the Biomass that produces maximum sustainable yield.

No score is shown for the Arctic Sea (FAO Region 18) because only 11 taxa harvested there, most with catches less than 1 metric ton. With this rate, normal analytical methods used by the Index would produce misleading results. 

The Sense of Place goal, evaluates the ocean’s intangible benefits to cultural, traditional, spiritual and aesthetic values. It is represented only by Iconic Species, because no Lasting Special Places exist in the open ocean.  Iconic species were evaluated based on risks of extinction as determined by the International Union for the Conservation of Nature (IUCN) Red-Listing process. Fifty-eight (58) species were evaluated for the entire sub-goal.  The Western Central Pacific Ocean received the highest score for Iconic Species (85). Lowest scoring were the Northeast Atlantic (61) Northwest Atlantic (63) and Arctic Sea (41).  Thirty species were assessed in the Northeast Atlantic Ocean and 29 in the Northwest Atlantic.  In both areas, one species was critically endangered (leatherback turtle); six species were endangered (sei, blue, fin and right whales; green and loggerhead turtles); eight species were vulnerable to extinction (thresher, white, basking, shortfin mako, porbeagle and whale sharks; sperm whale and polar bear); and two species were near threatened (tiger and blue sharks). Other species were at ‘least concern’ risk for extinction. 

Biodiversity is represented by its Species subgoal alone, because the absence of data prevents evaluation of the health of seafloor habitats. Species whose population status (increasing, stable or decreasing) had been evaluated by the International Union for the Conservation of Nature (IUCN) Red-Listing process were used in computing the score.

Species scores ranged from 84 in the North Eastern Pacific to 60 in the Arctic Sea, the Arctic Sea score being low primarily because of decreasing populations and poor status of a few mammal species, in particular polar bears and fin whales (as indicated by IUCN population assessments).