Parasite Causes Skin Tumors on Antarctic Fish, Climate Change Aggravates Infection

Numerous Antarctic fish have been discovered to have skin tumors all over their bodies. These tumors are thought to be caused by a parasite, according to research. Climate change makes the infection worse.

Tumor-Ridden Fish

The weird-looking fish was found by the authors in 2018 during their expedition to West Antarctica. They discovered that about 30% of the specimens from two species of crowned notothen had tumors. The skin tumors usually covered more than a third of the fish's body. The tumors are raised, pale pink, and rough. Four years before the publication of the study, the researchers visited the region, including Dallmann Bay and Andcord Bay, but there were no instances of fish with these tumors during the time.

The team quickly discovered that one species was widespread and that many of them had large tumors, according to Thomas Desvignes, the study's lead author, in a statement.

Fish Cancer and Climate Change

The research team examined the tumors once they got back to the lab and discovered that the fish had X-cell disease, a cancerous infection brought on by a new species of Xcellidae, a parasitic alveolate. This protozoan is the same kind that causes malaria. Prior reports of Xcellidae infections in wild fisheries in Iceland and Norway exist, but the mode of transmission is still unknown.

Fish belonging to the notothenioid family are infamous for their adaptations, which enable them to survive in the world's coldest waters. To survive in the chilly Antarctic waters, the fish evolved a glycoprotein that lowers their blood's freezing point to just below that of seawater (28.4 F).

According to the researchers, the sudden and sharp increase in Xcellidae infections may be linked to rising seawater temperatures as a result of climate change.

The West Antarctic Peninsula's glaciers are melting quickly, according to the study's authors, although sea bottom temperatures at the capture sites were not significantly different from those at other nearby localities. Antarctic bottom waters, which have been warming and getting fresher for a while, are being impacted by this.

The new Xcellidae species discovered to be infecting the Antarctic fish may spread more readily or be more infectious due to the warmer waters, or they may weaken the icefish, making them more vulnerable to infection.

Desvignes explains that when circumstances in life become difficult, some animals develop a higher risk of illness, Newsweek reports.

The ocean is becoming warmer as a result of rising global temperatures brought on by climate change. Since 1955, the upper ocean has warmed by more than 34 degrees Fahrenheit to the west of the Antarctic Peninsula, with the Antarctic Circumpolar Current warming the Southern Ocean more quickly than the rest of it. This, along with the resulting sea ice melting, is already having an impact on the entire Antarctic ecosystem, with changes in penguin distribution and a long-term decline in Antarctic krill abundance.

Current Progress and Future Plans

The team currently lacks the information and expertise to forecast how X-cells might be impacted by a changing climate. The dramatic situation in this population, as the authors noted, may foreshadow widespread biotic changes in host-parasite interactions brought on by changes in the abiotic environment, despite alarming predictions for continued changes in Antarctic climates.

To better comprehend and quantify the parasitic infection, how it spreads among fish, and how long-term climate change will affect it, the authors concluded that more research is necessary.

In a statement, Desvignes stated that they are putting together project proposals to return there and examine this specific outbreak, how it changed since 2018, and explore nearby areas to see if they can find the pathogen elsewhere or in other species.