Restored oyster reefs could add $12 trillion a year in ecosystem value, study says

A study published in Frontiers in Marine Science estimates that fully restored oyster reefs in the world's top 10 hotspot countries would deliver a gross ecosystem product (GEP) of $12 trillion each year. The study describes GEP as the ecological counterpart of the gross economic product. "Here we estimate that fully restored oyster reefs in the top 10 hotspot countries worldwide would yield a GEP of $12 trillion," said Dr. Matteo Convertino, an associate professor at Tsinghua University and the corresponding author of the publication.

The researchers imported thousands of geotagged records of oyster reefs from two public databases and used a machine learning algorithm to predict where reefs could exist worldwide. Their estimate weighed environmental measures including local water temperature, salinity, light, nutrient richness and oxygenation. Locations scoring 65% or higher for habitat suitability were classified as suitable, and the authors combined each score with a measure of ecosystem services to rate each location's "ecopotential."

The study reported the highest predicted ecopotential in 10 hotspot nations: the U.S., Australia, Chile, China, Japan, South Korea, Argentina, France, Germany and Italy. Across these countries, approximately 295,000 square kilometers (114,000 square miles), or 6% of their coastal zones, were deemed suitable. Oyster reefs currently occupy only 10% of that area, mainly in lagoons and bays, estuaries and river deltas, and only 23% of the suitable area is under any form of marine protection, according to the study.

The services the authors assessed include oysters for human consumption, water filtration, shoreline protection, recycling of nutrients through the food web and carbon sequestration. Oyster reefs also provide food, shelter and nursery grounds for fish and invertebrates, the study states. The authors said oyster reefs, like all coastal ecosystems, are under growing pressure from overexploitation, pollution and climate change, and that an estimated 85% of such reefs have been lost over the past century, especially in estuaries and river deltas.

The study's framing ties to the U.N.'s Sustainable Development Goal "Life below water," which calls for the conservation and sustainable use of coastal and marine resources to safeguard human well-being. The authors stated that for the reefs' full potential to be realized, oyster reefs around the world will need to be restored and protected.