An investigation, recently published in the scientific journal Fish & Shellfish Immunology, revealed that the increase in temperatures conditions the response of Harpagifer antarcticus and Harpagifer bispinis to diseases.

One of the consequences of climate change is the increase in ocean temperatures, which can affect countless marine species that live in an ecosystem disturbed by the presence of new diseases and the increase in anthropogenic activities.

This context motivated a group of researchers headed by Dr. Julia Saravia, belonging to the Doctorate program in Aquaculture Sciences at the Austral University of Chile (UACh), and Dr. Luis Vargas-Chacoff, tenured professor at the UACH Institute of Marine and Limnological Sciences, researcher at the Center for Dynamic Research of High Latitude Marine Ecosystems (IDEAL) and the BASE Millennium Institute, to analyze how temperature is a stressor in the development of Harpagifer antarcticus and Harpagifer bispinis, two species of fish that inhabit Antarctica and Patagonia, respectively.

Both organisms belong to the nototheniids, a group that arouses special scientific interest due to its presence inside and outside Antarctica. This makes it possible to compare species with a close common origin, but which inhabit thermally different zones, being the predominant group of fish in the white continent.

The study determined that Harpagifer bispinis showed a lower immune response to increasing degrees Celsius. © Mauricio Ergas.

The work team collected specimens from King George Island (Antarctic Peninsula) and Punta Arenas to then simulate viral and bacterial infections, both in fish and in primary cell cultures (in vitro). The samples were exposed to three different temperatures (2, 5 and 8 degrees Celsius) to determine their reaction.

“We were not only interested in evaluating the response of the whole organism, but also the isolated response of its immune cells to infections in the presence of thermal variations,” explained Dr. Saravia, who is also a researcher at the Laboratory of Antarctic and Subantarctic Genomics and Molecular Ecology (LAGEMAS).

The analysis, published in the scientific journal Fish & Shellfish Immunology, showed that at 2°C none of the species responded to the immunostimulants, but they did as temperature increased (5 and 8°C.) The study determined that Harpagifer antarcticus presented a greater immune response to the increase in degrees Celsius.

“Although we would expect both specimens to respond in their natural conditions, these differences could be associated with specific ecological relationships between host and pathogens, as well as thermal thresholds for the proliferation of microorganisms,” explained Saravia.

Dr. Vargas-Chacoff, corresponding author of the study, assured that “this behavior is interesting because the temperature, rather than the infection condition, regulates the response. Therefore, climate change will affect the immune system of these species and will condition how they will face future diseases.”

Read the study here.