Antarctic fish are developing strange tumors that are believed to cause disease outbreaks

The news raises alarm and it is for a specific reason: the researchers of the University of Ohio believe a parasitic disease is spreading due to climate change after finding large numbers of Antarctic fish with grotesque skin tumors due to a never seen before in the polar region.

“The tumors are pale, pink, raised, rough and have appeared in various places on the trunk and head, in some cases covering more than a third of the surface of the fish’s body,” says the study published by the researchers in a section. ‘UO.

Thomas Desvignes, chief scientist on the research expedition in 2018 and lead author of the paper, said in a statement: “When living conditions become difficultanimals become more prone to disease. “

Changing conditions include rising air temperatures and melting glaciers. “The waters of the Southern Ocean have been environmentally stable and chronically cold, hovering around the freezing point for the past 15-20 million years,” shared the team in the study published in the journal iScience.

“However, the climate in Antarctica is changing rapidly with rising air temperatures and melting glaciers contributing to warmer and colder bottom waters, “the study continues.” Strong abiotic stressors are already affecting Antarctic wildlife. highly endemic and specialized causing a cascade of responses from the molecular to the community level “, say the experts.

Desvignes, together with the biologist of the OU John Postlethwaitvisited a small fjord in the West Antarctic Peninsula to study a unique group of fish called notothenioids. The team was intrigued by this fish because it poured into the Southern Ocean from the Atlantic and evolved to withstand the freezing waters.

This includes developing a specialized protein that prevents the blood from freezing. The fjord is usually full of obstacles at the time of year the team visits, but due to rising temperatures, they could venture out and start fishing.

Scientists studied specimens at Andcord Bay and Dallmann Bay. “Just when we put the first bottom trawl back on deck, we realized that one species was really abundant and many of them had large tumorsDesvignes said, “When we saw it, we immediately realized we had to do something,” he said.

The team collected several infected fish and took them to a laboratory for further analysis. There they established that the parasites that caused the tumors they belonged to a different genus than other parasites implicated in previous cases of X-cell disease.

“It can be difficult to attribute a disease outbreak to a specific cause. But Antarctic ecosystems are particularly vulnerable to the effects of climate change and they are experiencing changes particularly fast, “according to the researchers.” When the ice melts, for example, the nearby water becomes less salty. And the bottom water where these notothenioids live is getting hotter and fresher, especially quickly. “

Desvignes suggests it the fish may feel pressured when the waters warm up and ecosystems change.

“Climate change could also affect the parasite’s life cycle, perhaps making it more effective in spreading and infection,” he said. Other non-weather explanations could also explain the outbreak, but the team said more data needed before a concrete conclusion can be reached.

“Maybe the parasite has a long life cycle and only manifests itself in a disease outbreak from time to time, and we could have been there by accident when it happened,” said Desvignes, who said it was due to Covid-19. and the logistical challenge of visiting Antarctica, they have not been able to return to the area since then.

“We are preparing project proposals to go back and study this specific outbreak, how it has evolved since 2018 and explore adjacent areas to try to see if we can detect the pathogen in other places and in other species, ”Desvignes said.