Methods
A FRAMEWORK FOR UNDERSTANDING
A goal scores highest when the maximum sustainable benefit is achieved through methods that do not compromise the ocean’s ability to deliver that benefit in the future. The Index score is the average of the 10 goal scores.
Calculating the Goals
All goals are measured in relation to a reference point, or target. The reference points and components used to evaluate a goal's Status, Trend, Pressure, and Resilience vary by goal. For a description of each goal and its importance, reference point, and components, refer to the goal pages.
To find out how each goal score was calculated, download the Paper and Supplementary Online Materials.
10 Human Goals
Provision
Seafood is a fundamental component of our diet, contributing to the basic protein needs of nearly half of the world’s population. This goal measures the amount of seafood harvested primarily for human consumption and how sustainable it is.
Food Provision is divided into two sub-goals: Wild-caught commercial seafood and Mariculture, or ocean-farmed seafood.
Opportunities
Local fishing provides jobs and feeds families in communities around the world, especially in developing nations. This goal measures the degree to which a nation permits or encorages artisanal fishing compared to the demand for fishing opportunities, and in the future will include the sustainability of artisanal fishing practices.
Products
From seashells and sponges to aquarium specimens, non-food ocean resources support local economies and international trade. This goal measures the amount and sustainability of harvest levels pertaining to marine ornamental fish specimens for aquariums, coral products, fish oil, seaweed, sponges, and shells.
Storage
The ocean and the coastal plant habitats fringing its shores play a major role in slowing global warming by absorbing and storing atmospheric carbon (CO2). This goal measures the current condition or area of coastal plant habitat coverage relative that in ~1980.
Protection
Coral reefs, mangroves, seagrasses, salt marshes, and sea ice act as natural buffers against incoming waves, protecting people from storm damage, flooding, and erosion. This goal assesses the amount of protection these coastal habitats provide by measuring the current area they cover relative to the area they covered in the recent past.
& Economies
The ocean is an important source of jobs and revenue for individuals, businesses, and communities worldwide. This goal measures a country’s ability to maintain coastal livelihoods and economies in ten marine sectors, from shipping and transportation to wave and tidal energy.
This goal is divided into two sub-goals: Livelihoods, and Economies.
& Recreation
Whether it's a day at the beach, snorkeling on reefs, or a weeklong cruise, people enjoy visiting coastal areas and taking part in the many recreational activities that they offer. This goal evaluates the attraction of (priced and un-priced) coastal and marine activities by measuring the number and length of international tourist visits, and sustainability as indicated by tourist density.
Place
People derive a sense of cultural identity from coastal and marine areas. For people living both near to and far from the ocean, knowing that particular species or places exist provides important cultural, spiritual, and personal value. Sense of Place measures the condition of culturally iconic species and the percentage of protected places within a country.
Sense of Place is divided into two sub-goals:
Iconic Species, and Special Places
Waters
Waters contaminated by pollutants have negatively impact human health, livelihoods, and recreational opportunities, as well as the health of marine wildlife and ecosystems. This goal measures the degree to which waters are polluted by eutrophication (excess nutrients mostly from fertilizers or sewage), chemicals, pathogens, and trash.
An ocean filled with diverse species and flourishing habitats can produce food, jobs, recreation, coastal protection, and other benefits now and in the future. This goal measures the conservation status of marine species and the condition of key habitats that support species richness and diversity.
Biodiversity is divided into two sub-goals: Species and Habitats.
GLOBAL INDEX SCORE
Calculating the
Ocean Health Index
The Index calculates scores using data for each country’s shoreline and Exclusive Economic Zones (EEZ). EEZs extend outward 200 nautical miles from shore.
Each goal is evaluated on the basis of four dimensions. Present Status is a goal’s current value (based on the most recent available data) compared to a reference point. Trend is the average percent change in the present status for the most recent 5 years of data. Pressures are the sum of the ecological and social pressures that negatively affect scores for a goal, and Resilience is the sum of the ecological factors and social initiatives (policies, laws, etc) that can positively affect scores for a goal by reducing or eliminating pressures.
The score for each goal is the average of the values for the Present Status and Likely Future Status. Likely Future Status is determined by combining the Trend, Pressures, and Resilience values. Trend is considered twice as important in indicating the likely future state as the combined role of Resilience and Pressures, because trends are a more direct measure of the future trajectory of a goal. Resilience measures require more time to take effect, and changes are often slow to register. The Ocean Health Index does not attempt to indicate conditions further than 5 years into the future.
likely future status is calculated as:
Likely Future Status = Present Status x {1 + (0.67 x Trend) + 0.33 x (Resilience – Pressures)}using likely future status, each goal score is computed as:
Goal Score = (Present Status + Likely Future Status) divided by 2.The Ocean Health Index combines the 10 goal scores to calculate the overall score for each EEZ. The global score is the area-weighted average of the scores for all EEZs. Individual goals are considered to be equally important, so each represents 10 percent of the global score.
