Pew researching carbon-sink, fisheries-preservation potential of eelgrass in China

Published on
August 27, 2021
A research project is under way into the conservation of a sea grass that could improve China’s fishery sustainability.

A research project is examining how the conservation of a sea grass could improve China’s fishery sustainability, while also acting as a carbon sink to help the country achieve its stated climate goals.

Pew Marine Fellow and marine biologist Songlin Wang is leading a research project conducted by the Qingdao Marine Conservation Society (QMCS) to study the Bohai Bay Eelgrass Bed, an unprotected area featuring one of the last remaining ecosystems of its type in China’s marine waters.

Eelgrass beds, in the form of underwater meadows of the common eelgrass Zostera marina, were widely distributed in intertidal and subtidal zones of the Bohai Sea and the northern Yellow Sea off China’s coast. However, most of those beds are now gone, according to Wang.

“In the past 30 years, up to 90 percent of [China’s] eelgrass was lost in formerly vibrant habitats due to large-scale reclamation, sand mining, destructive fishing, and irresponsible mariculture practices, as well as water pollution,” Wang told SeafoodSource.

China’s commitment to carbon neutrality, made last September, can be accelerated by the preservation of eelgrass, Wang said. One of the most widespread and abundant seagrass species in the Northern Hemisphere, eelgrass absorbs carbon dioxide and methane – both climate-warming greenhouse gases – and stores them in its root system, according to a 2019 research article published by Pew.

Eelgrass habitats also serve as valuable sites for breeding and feeding of commercially valuable fish, according to Wang. Protecting the eelgrass also makes economic sense for fishing communities, Wang said – in the past decade researchers have found “biodiversity and fisheries resources are very abundant” within a stretch of eelgrass in the Bohai Bay. Fishing methods deemed “eelgrass friendly” by Wang are cages and pots favored by artisanal fishermen to target demersal fish, crab, mantis shrimp, octopus, and whelks.

“The most eco-friendly fishing method in an eelgrass bed I witnessed was in Dongchudao [in] Weihai, where villages actively preserve eelgrass bed for [a] spiky sea cucumber stock enhancement fishery,” Wang said. “They release hatchery produced juvenile sea cucumbers to their natural eelgrass bed and then hand-pick the sea cucumbers once they reach harvestable sizes.”

Yet fishing practices like bottom trawling and the use of pumps to suck up crabs are still common in China, and do significant damage to eelgrass, Wang said.

But the Chinese government may intervene in the future as it seeks ways to sequester carbon. Wang Hong, vice minister at the Ministry of Natural Resources and director of the State Oceanic Administration, recently said China plans to add marine carbon sinks such as fisheries and marine microorganisms to its list of ecosystems that function as “biological pumps,” storing carbon in the deep sea.

The city of Weihai in the province of Shandong, which has a significant fishing industry, is preparing to develop “blue carbon” schemes, Wang said. Another key fisheries province, Zhejiang, is researching marine carbon sink ecosystems province-wide, with four cities to preparing to operate blue carbon trial projects.

Photo courtesy of I. Noyan Yilmaz/Shutterstock

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