Latest news with #InstitutefortheOceansandFisheries
National Observer
5 days ago
- Health
- National Observer
Distant Covid cousin correlates with calamitous oyster die-offs
A previously-unknown virus distantly related to Covid is "strongly associated" with mass die-offs of farmed Pacific oysters in BC, researchers have found. The virus showed up in about two-thirds of the dead and dying oysters the research team collected during a mass die-off on two oyster farms in BC in 2020. Wild oysters collected near the farms weren't infected, hinting at a possible link between the virus and the mass die-offs. The virus — Pacific oyster Nidovirus 1 — is specific to oysters, and doesn't pose a health risk to humans. "We have not demonstrated a causative effect between this virus and mortality at this point, but they're highly associated," said Curtis Suttle, a study co-author and professor of earth, ocean and atmospheric sciences, botany, microbiology and immunology, and the Institute for the Oceans and Fisheries. Pacific oysters are the primary shellfish farmed in BC, with the industry worth about $16 million in 2023. In recent years, the province's oyster farmers have lived under the threat of so-called "summer oyster mortality syndrome," a phenomenon where up to 90 per cent of a crop of oysters die within a few days of each other right before reaching market size. The mass die-offs are closely linked to higher water temperatures. As the climate crisis has deepened, BC's average water temperatures have increased by between 0.2°C and 0.6°C, particularly in shallow waters where oysters grow best. Climate change is also causing more extreme temperature swings — ocean heatwaves — which stress the bivalves further, said Suttle. "It's been pretty devastating for our industry," said Nico Prins, executive director of the BC Shellfish Growers Association. "This summer oyster mortality syndrome is a cascade of various stressors that just combine to just be too much for the poor animal to deal with, and they die." He doesn't think the virus will be a "smoking gun" pinpointing the cause of the mass die-offs, but could help offer more insight. Suttle said that his team found that farmed Pacific oysters in Europe and Asia were also routinely infected with the virus, but those infections weren't linked to mass die-offs. A previously-unknown virus distantly related to Covid is "strongly associated" with mass die-offs of farmed Pacific oysters in BC, researchers have found. But Suttle said the findings should be a reminder that oyster farmers need to be cautious about moving oyster seed — baby oysters — between farms and bodies of water. Most oyster farms don't produce their own seed, instead requiring a labour-intensive process where seed producers induce spawning in broodstock, then grow the larvae into small oysters that are sold to farms. Once at the farms, the oysters are suspended in underwater cages, where they grow to market size. Fisheries and Oceans Canada has few restrictions on where oyster seed can be sold and BC only has a handful of oyster seed producers. Stricter rules apply to older oysters, which can only be moved from farm to farm within specific zones, explained Prins. Jessie McMillan, operations manager at Manatee Holdings, one of BC's oyster seed producers, said that while he'll "definitely be paying attention" to emerging research about the virus, he isn't panicked. "There's no way to predict if it's a causative agent," he explained. Oysters stressed by heat or other well-known factors could be more susceptible to carrying the virus, even if they're asymptomatic. He's more concerned about problems that cause known stress to the shellfish, such as harmful chemicals and bacteria that lax provincial and federal pollution and wastewater regulations allow to enter the ocean, as well as climate change.
Global News
17-06-2025
- Science
- Global News
Wildfires can have dramatic effect on water quality, UBC research finds
While the smoky greenhouse gas emissions get most of the attention, new research from the University of British Columbia suggests wildfires may be producing several other troubling environmental impacts. Research by the Institute for the Oceans and Fisheries raised concerns that runoff from wildfire zones could both be harming water quality and ecosystems and be speeding up the process of climate change. In one recent study, professor Brian Hunt and research scientist Emily Brown focused on the Fraser River, combing through 20 years of historical wildfire and water data. They concluded that more than 16 per cent in the variation of water quality could be linked to fires. 'We saw that wildfires lead to increases in the concentrations in metals and nutrients, including things like lead, copper and nitrogen, which could eventually lead to downstream negative effects on river and ocean ecosystems including impacting fish and shellfish and the aquatic ecosystems overall,' Brown said. Story continues below advertisement 1:50 Canada's summer forecast raises fears for worsening wildfires Wildfires are a natural part of the province's environment, Brown said, meaning the presence of such materials shouldn't necessarily ring alarm bells. Get breaking National news For news impacting Canada and around the world, sign up for breaking news alerts delivered directly to you when they happen. Sign up for breaking National newsletter Sign Up By providing your email address, you have read and agree to Global News' Terms and Conditions and Privacy Policy But she said with climate change increasing the frequency and intensity of the fires B.C. sees, there is room for concern. High concentrations of metals can end up in fish and shellfish, both harming them and causing potential health hazards for humans that eat them. High concentrations of nutrients can cause algae to bloom, potentially sucking oxygen from the water and releasing toxins. 'So the concern is more that if this continues to happen, then we can see negative impacts,' she said. Also troubling is the potential for wildfire-tainted runoff to reinforce the cycle of climate change itself. Story continues below advertisement That finding, published in another recent study, revolves around 'black carbon,' a material of tightly-clustered carbon atoms that forms when carbon that is in trees or vegetation is burned. 1:38 Canada's 2023 wildfires released more carbon than most of the world's top economies Because those tightly packed molecules are hard to break down, scientists believe they could help sequester carbon, keeping it out of the atmosphere, Brown explained. 'But what our research is showing is that as the climate is changing and the Fraser River is changing from being more snow-driven to maybe a bit more driven by rain, we could be seeing smaller particles of black carbon entering the ocean and ones that are easier to break down,' she said. 'And that could reduce the ability of black-carbon to sequester carbon from the atmosphere, and it could be broken down when it enters the ocean more quickly and then released back as carbon dioxide.' Story continues below advertisement Brown said the research is another reminder of the importance of local action, like respecting fire bans, and broader climate action. She said it also points to the importance of prescribed and cultural burning, which can help ensure the province's forests are more resilient to wildfires.
