Collecting Antarctic Fishes for Science - MOO Antarctica

How does one collect fish under an 8-foot-thick (2.5m) solid cover of ice in the near-freezing waters of Antarctica's Southern Ocean?

Our preferred method is to do it while diving! All you need is a typical pet store green aquarium net, a catch bag and whole lot of diving gear!

In this video, shot at locations some distance away from the McMurdo Oceanographic Observatory, project leader Paul Cziko is collecting primarily Trematomus bernacchii, a very abundant Antarctic Notothenioid fish species.

This species' blood is loaded with antifreeze proteins, called antifreeze glycoproteins, which protects them from freezing to death in icy waters where your everyday fish would freeze solid almost instantly.

Near the end of the video we also collect a few young (less than 1 yr old) fishes up near the underside of the ice and, with frozen hands, delicately transfer them to special collection bottles to prevent any injuries to them.

Fishes shown here were collected to support studies aimed at quantifying (counting) the number of microscopic ice crystals that occur INSIDE their bodies. We would like to know how their "ice load" varies with the environmental conditions (seawater temperature, iciness) that these fish inhabit.

While antifreeze protein-bearing notothenioids do not freeze instantly in this 28°F (-2°C) water, environmental ice crystals (those that exist in the seawater in which they live) still manage to invade their bodies.

It is still not known when or how the ice crystals get inside the fishes' bodies, what happens to them once inside (can the fish remove them, melt them), nor whether accumulating ice crystals could be harmful to the fish over the 10 to 20 years of their lives (imagine what would happen to you if your blood became the consistency of an ice slushy).

Some of the collected fishes were used in our studies. Some were released unharmed after measuring and weighing.

In our science work we make every attempt to minimize disturbance to the environment and collect and use only the fishes we absolutely need for our studies.

Our project, the demonstrated fishing technique, and our experimental protocols are approved and carried out under the University of Oregon Animal Care and Use Committee guidelines for the use of animals in research (protocol approval 17-14). The institution has an Animal Welfare Assurance on file with the Office for Protection of Research Risks (A-3009-01).

For more info, please visit www.moo-antarctica.net

The McMurdo Oceanographic Observatory is a project managed by Paul A. Cziko at the University of Oregon USA, supported by the US Antarctic Program and funded by the US National Science Foundation.