Global Ocean Health Remains Relatively Stable Over Past Five years, Study Says

July 5, 2017

Rapid sea ice loss, coastal protections reduction caused declines in ocean health in many Arctic and sub-Arctic countries

ARLINGTON, Va. (July 5, 2017) – While global ocean health has remained relatively stable over the past five years, individual countries have seen notable changes, according to a study published today in the open-access journal PLOS ONE by Dr. Benjamin Halpern from University of California Santa Barbara, Johanna Polsenberg, senior director of the Ocean Health Index at Conservation International and other colleagues.

Using an innovative tool developed by Conservation International and National Center for Ecological Analysis and Synthesis (NCEAS) called the Ocean Health Index, the researchers found global ocean wellness flatlined at a score of 71 out of 100, which indicates that oceans aren’t dying but neither are they thriving.

Called the “Fitbit for oceans”, the Ocean Health index has been used to assess ocean health on the local and regional scale, measuring factors such as biodiversity, coastal protection and clean waters to help inform regional policies. In this study, Halpern, Polsenberg and colleagues analyzed five years’ worth of data for 220 countries, seeking potential drivers and implications for the changes that they observed.

That global ocean health has been fairly stable over the past five years is not unexpected since the health of the world’s oceans does not change rapidly over a relatively short time period. What was notable were changes individual countries. For example, rapid loss of sea ice and the consequent reduction of coastal protection from that sea ice was responsible for declines in overall ocean health in many Arctic and sub-Arctic countries. Meanwhile, improvements in the management of wild-caught fisheries, the creation of marine protected areas and decreases in the harvest of natural products, or non-food products like sponges and seashells, were among the factors attributed to improvements in other coastal countries.

“Each year we do this assessment we learn something about where oceans are healthy and not as healthy, and get a little more insight into what might be causing those changes,” said Dr. Ben Halpern, lead author of the study, professor and research biologist at the Marine Science Institute at the University of California, Santa Barbara. “But with five years of assessment we finally have enough information to get a clear signal of what’s going on. Countries that are seeing notable improvement in their oceans are taking concrete actions to make things better, like creating marine protected areas. This is the first anyone has been able to do this — measure the health of our oceans in a comprehensive way and track changes with a single measure.”

While the Ocean Health Index at Conservation International was capable of predicting short term changes in global ocean health, the authors suggest that investment in additional resources for measuring changes on a global scale would greatly help with management and protection of ocean health.

“We believe the Ocean Health Index gives reason for hope by providing a detailed diagnosis of the state of ocean health and a framework that allows countries to identify and prioritize the most necessary resilience actions to improve ocean health — now and for the future,” says Polsenberg.


The National Center for Ecological Analysis and Synthesis engages the best minds in ecology to address critical global challenges affecting nature and human well-being. It nurtures the discovery of breakthrough ideas and solutions by bringing together interdisciplinary teams of scientists to synthesize existing data and reap new insights. Established in 1995 and affiliated with UC Santa Barbara, it was the first synthesis science center of its kind and has helped transform how scientists do research for the benefit of nature and people. Learn more about NCEAS and follow us on Twitter.

About Conservation International

Conservation International uses science, policy and partnerships to protect the nature people rely on for food, fresh water and livelihoods. Founded in 1987, Conservation International works in more than 30 countries on six continents to ensure a healthy, prosperous planet that supports us all. Learn more about Conservation International and its groundbreaking “Nature Is Speaking” campaign, and follow Conservation International’s work on Facebook, Twitter, Instagram and YouTube.