(Image: Enrico Sacchetti)

ANTARCTIC silverfish aren’t really silver – at least not while they are alive. They start off pink with a silver shimmer that only darkens into the metallic hue they are known for after death. Living in such frigid conditions, silverfish (Pleuragramma antarcticum) have some neat survival tricks, for example, they make their own antifreeze protein.

These fish are crucial to the survival of other inhabitants of the chilly waters, namely Adélie penguins and Weddell seals. But relatively little is known about their life cycle. We do know, however, that silverfish have declined in parts of the Antarctic, perhaps due to climate change.

Biologists from Italy’s Institute of Marine Sciences in Venice are trying to learn more. In the Ross Sea, part of the Southern Ocean, silverfish are the most abundant kind. The team sent divers (above) and remote-operated vehicles to sample the ice, and found that silverfish lay eggs (below) that float up and cluster on the underside of the ice shelf. The ice provides an incubating area for the eggs, and protects them from predators.


(Image: Enrico Sacchetti)

Photographer Enrico Sacchetti spent a couple of weeks with the Italian biologists. For this shot, he had to lie on the ice and wait for the divers to return to their borehole. “The temperature hovered between -22.0 °C and -48.9 °C,” he says, nonchalantly claiming that the low humidity made the cool temperature “acceptable”. “But if the wind picked up even just slightly, we all cried like babies,” he admits.

This article appeared in print under the headline “Silver in the sea”