Climate change challenging Massachusetts oyster fishery

By Sarah Garcia
BU News Service

BOSTON — As climate change transforms ocean waters around the globe, the rapidly growing Massachusetts oyster industry is feeling the heat.

Effects such as warming waters, rising sea levels, coastal acidification, and stronger storms have created roadblocks for an industry with otherwise tremendous momentum.

The mollusk shellfish harvest from Massachusetts state waters in 2018 was valued at over $45 million, according to a report released by the Massachusetts Shellfish Initiative in September, “with the state’s rapidly growing shellfish aquaculture industry contributing over $28 million of the landed value in 2018.” Mollusk shellfish are oysters, clams, mussels and scallops.

Although it is difficult to pinpoint just one effect of climate change on his oyster farms, Chris Sherman, a former oyster farmer and current president of Island Creek Oysters, said the shoreside infrastructure is very clearly affected. The industry’s main concerns are increasing sea levels and more frequent storms, said Sherman, whose oyster farms are in Duxbury.

A storm that hit the Cape just over a week ago is a prime example, said Ben Lloyd, oyster grower and president of Pangea Shellfish Co., who also owns farms in Duxbury.

“It was supposed to be 50 mile an hour winds and we ended up in Duxbury with 80-plus mile an hour winds,” Lloyd wrote in an email. More frequent storms are the most prominent effect of climate change that Lloyd has seen since he started his business 18 years ago.

Powerful storms such as these cause damage to equipment and overturn cages, resulting in a loss of oysters, Lloyd said.

Climate change impacts are being mitigated through preemptive measures taken by farmers.

“Better gear, better genetics, better shoreside infrastructure are all needed to protect the incredible foundation the New England farmed shellfish industry has built over the last 20 years,” Sherman wrote in an email.

However, Massachusetts does little in comparison to other areas where shellfish are farmed when it comes to innovations used to combat the impacts of climate change, Sherman said. Other states are modernizing their infrastructure as the industry evolves, he said.

“As we look to overseas markets, it is nearly impossible for East Coast oysters to compete with more sophisticated production from places like France and Australia or even the Pacific Northwest,” Sherman wrote.

Increased storm frequency is not the only problem linked to climate change that the Massachusetts oyster industry faces.

“Something that is kind of a concern to all of us, we haven’t necessarily seen it yet, but there is disease — and I want to be really clear about this, there’s diseases that affect oysters but not humans,” Lloyd explained. “So these are diseases that can kill oyster populations.”

Hatcheries are working on disease resistance and prevention methods for a parasite known as MSX, said Lloyd, who has dealt with outbreaks before. MSX kills oysters in their early stages of life, according to a report by the Virginia Institute of Marine Science.

With an increase in ocean temperatures, Lloyd worries that diseases such as MSX and Dermo — another parasite that infects oysters in their early stages, typically in their second year — will become more prevalent.

According to the institute, with Dermo, “Moderately to heavily infected oysters usually exhibit a reduction in growth rate, poor condition, and reduced reproductive capacity.”

Water temperature and quality are the two most important environmental factors that contribute to the occurrence of Dermo and MSX.

Ocean temperatures off New England have risen by an average 3 degrees since 1901, according to Climate Central, an organization of scientists and journalists documenting the effects of climate change. The coastal waters of New England have experienced the most significant warming around the nation, according to Climate Central.

“[These effects] act as stressors on our ocean and coastal environments resulting in dead zones, altered food webs and poor water quality,” said Claudia Mazur, a Ph.D. student at Fulweiler Lab. “Warmer waters reduce the ability for our oceans to absorb CO2, increasing CO2 emissions which can further warm our atmosphere.”

One of the main focuses of the Fulweiler Lab team’s research is how climate change affects ecosystems at both a local and global level.

Higher ocean temperatures and fertilizer run-off fuel algae blooms, Mazur said. When the blooms die, they release carbon dioxide, lowering the pH levels of the water and increasing acidity. This is known as coastal acidification.

“I know as scientists we need to better understand how the interaction of these local and global changes will influence future pH conditions of our coastal waters,” Mazur wrote in an email. “If we can do this successfully, then we can help the shellfish industry mitigate any practices that may be sensitive to these future acidic environments.”

Coastal acidification is a “pressing issue” for shellfish farmers, Sherman said. And further offshore, ocean acidification also poses a threat.

“Our oceans have the ability to absorb one-third of our atmospheric CO2 emissions,” Mazur explained. Atmospheric absorption leads to an increase in hydrogen ions. The problem for shellfish arises as the ocean naturally binds its “free floating carbonate” to the hydrogen ions.

“Unfortunately, as more and more H+ bind with carbonates in seawater, there is less available for oysters or any shell-making organisms to build their shells,” Mazur said.

Currently, the effects of ocean acidification off the East Coast are not as significant as what the oyster industry on the West Coast is experiencing, according to Lloyd.

“But hatcheries certainly on the East Coast are trying to be proactive with it and conditioning water and things like that to get the pH to where it needs to be,” Lloyd said.

Shellfish such as oysters are critical to ocean health as they filter nutrients and create natural storm barriers, according to the Massachusetts Shellfish Initiative report, and efforts to protect them are vital.

“As a result of the ability for shellfish to shape the surrounding environment and control key factors important to storm protection, water quality, and fisheries production, promoting healthy shellfish populations is instrumental to the health of Massachusetts coastal waters,” according to the report.

This article was originally published in the Daily Hampshire Gazette.