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Antarctic fish are increasingly threatened by climate change

A new study published in the journal Nature Communications Biology has revealed a worrisome correlation between warming waters, decreased sea ice levels, and reduced abundance of Antarctic Silverfish. If this trend continues, the Silverfish could be brought on the brink of extinction, an outcome that would affect many other marine populations too.

The Antarctic Silverfish (Pleuragramma antarctica) comprises over 90 percent of adult and larval fish biomass in the coastal areas of the Southern Ocean. Due to their availability and abundance, they are important prey for many other marine species, including seals, penguins, seabirds, and other fish.

Currently, their natural habitat faces significant changes due to global warming. From 1945 to 2009, the average winter air temperature in the region increased by six degrees Celsius (10.8 degrees Fahrenheit). At the same time, the annual duration of sea ice decreased by almost two months.  

“The study area is one of the most rapidly warming regions on Earth, with increases in air and water temperatures leading to substantial reductions in sea-ice coverage over the last half century,” said study co-author Deborah Steinberg, a professor of Marine Biology at the Virginia Institute of Marine Science (VIMS).

In order to investigate the correlation between climate change and the abundance of Antarctic Silverfish populations, Professor Steinberg and her colleagues analyzed over 7,000 larval fish specimens collected over 25 years (1993-2017) as part of the Palmer Long-Term Ecological Research program (an ongoing investigation of the effects of climate change on the ocean food web along the western coast of the Antarctic Peninsula). They found that warmer sea surface temperature and decreased sea ice were strongly associated with reduced larval abundance, and consequently to declining populations of mature Antarctic Silverfish.

“This is the first statistically significant relationship reported between sea ice and the long-term abundance of any Antarctic fish species,” said study lead author Andrew Corso, a doctoral student in fisheries sciences at VIMS.

“With continued regional warming, these fish could disappear from the region entirely, triggering major changes in the marine ecosystem,” he warned.

Image Credit: Andrew Corso/VIMS

By Andrei Ionescu, Staff Writer 

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