We are always hearing about how the ocean’s health is in peril. However, what does that really mean? Are all of the oceans at threat, as one huge connected entity, or do specific regions face greater alarms than others? A recent study published in PLOS ONE analyzed data over five years from the Ocean Health Index for 220 countries, and determined that in general global ocean health has remained mostly stable while specific countries have seen significant changes.
Benjamin Halpern from University of California Santa Barbara, USA and colleagues spearheaded the study and when analyzing the data they were looking particularly for potential drivers and implications that could explain the changes that they saw in certain ocean regions. The regions that experienced the most notable declines in health were mainly Arctic and sub-Arctic countries. This is likely the result of the fast-paced melting of glaciers and sea-ice, which has made coastal marine areas more vulnerable. The authors think that higher health reports in other regions of the world could have been due to improvements in wild-caught fishery management, the creation of marine protected areas, and decreases in harvesting of fish, according to the study.
The Ocean Health Index is a crucial tool to assessing assess ocean health on a big and small scale. It takes into account biodiversity, coastal protection, and clean waters and calculates a score which is useful for environmental policies.
The Ocean Health Index takes many factors into account. Photo OHI
"One of the things that's so powerful about the Ocean Health Index is that it allows you to compare the health of oceans any place on the planet, over time, with a directly comparable measure," says Benjamin Halpern. "You can ask some of the most basic yet most important questions about the state of our planet: how are the oceans doing, and what factors are driving changes in ocean health. We can finally start answering those questions."
Nevertheless, the Ocean Health Index does lack data in some aspects, making it a sufficient test for short-term projections but not long-term models. “If countries and the global community hope to achieve and maintain healthy oceans, we will need to dedicate significant resources to measuring what we are trying to manage,” writes the study.