Why We Need to Prepare for a More Acidic Ocean—And How Fishers Are Leading the Way

The ocean plays a crucial role in regulating the global carbon cycle, storing 60 times more carbon than the atmosphere and absorbing nearly 30% of human-caused CO₂ emissions.

However, this carbon absorption comes at a cost—causing ocean acidification, a process that threatens marine ecosystems around the world. If current emissions continue, the acidity of surface oceans is expected to rise by 100%-150% over pre-industrial levels by 2100. For British Columbia, this issue is especially urgent. Acidification levels in BC's nearshore waters are already 40% higher than pre-industrial levels, surpassing the global average increase of 30%. In 2019, ocean acidification was formally recognized by the Provincial Government as a major environmental threat—a threat that disproportionately impacts coastal and Indigenous communities who rely heavily on seafood for their sustenance and livelihoods.

What is Ocean Acidification?

Ocean acidification occurs when the ocean absorbs carbon dioxide (CO₂) from the atmosphere, causing a chemical reaction that lowers the water’s pH levels. This drop in pH reduces the availability of carbonate ions, which are essential for marine organisms, particularly those that rely on calcium carbonate to form their shells and skeletons. On the West Coast of Canada, ocean acidification is amplified by natural processes like upwelling, where cold, CO₂-rich water rises from the depths to the surface. These processes, combined with local pollution, make BC’s marine ecosystems particularly vulnerable.


How is Ocean Acidification Affecting the Marine Environment?

Ocean acidification has the potential to disrupt marine ecosystems at every level, from plankton to top predators. It is particularly harmful to shellfish populations, as these organisms depend on carbonate ions to build their calcium shells. As pH levels drop, shellfish like oysters, clams, and mussels experience slower growth, weaker shells, and higher mortality rates, especially in their larval stages. For BC's shellfish industry, this could mean smaller harvests and economic losses in the near future.

Moreover, the broader food web is at risk. Some plankton species, the foundation of the marine food chain, are sensitive to changing pH levels. If these small organisms are impacted, larger species—including commercially important fish, seabirds, and marine mammals—may experience a ripple effect as their food sources dwindle. This makes it essential to understand how acidification affects different species and ecosystems along the BC coast.

 

* Landed value, 5 year average (2017-2022) in millions of dollars.

Filling the Gaps: Fishers as Data Collectors

One of the key challenges in addressing ocean acidification is the lack of detailed, location-specific data. While there has been significant progress in monitoring pH levels in some regions, much of BC's vast coastline remains under-monitored. 

This is where fishers can help! Our OAH Monitoring Program is equipping commercial fishers with the tools to collect water samples and record essential data—such as temperature, salinity, CO₂ and O₂ levels, and geographic location—this program helps fill a crucial gap in BC’s ocean acidification monitoring efforts. Fish harvesters travel to areas that are often beyond the reach of traditional research programs, such as fjords, remote inlets, and sparsely populated regions. These locations are particularly important because they can have unique environmental conditions that vary significantly from more frequently monitored regions.

 

Guy Johnston aboard his fishing vessel, Michelle Rose. Guy is one of the fishermen
taking part in the project by collecting water samples during his fishing trips. 

 

The data fishers collect will be integrated into a larger database and shared with the Hakai Institute, which conducts ecosystem research on the central BC coast. This data collected by fishers will help provide a more comprehensive understanding of how ocean acidification is impacting different regions of BC’s coastline.The data fishers collect can also help inform management decisions and conservation efforts, ensuring that marine resources are sustainably managed in the face of acidification.

For fishers themselves, participation in this program is more than just a data-collection exercise—it’s a way to take an active role in safeguarding the future of the marine environment and the fisheries that sustain their livelihoods. As stewards of the ocean, fishers have a unique perspective on the health of the waters they fish, and their contributions to scientific research are invaluable.

 

We acknowledge that this project spans the entire coastline of British Columbia and occurs on traditional territories of numerous First Nations, who have stewarded these lands and waters since time immemorial.  

This project would not be possible without the generous funding provided through the Climate Ready BC Seafood program of the BC Ministry of Agriculture and Food, and Tula.


Sources: