Many of the fish down here are red-blooded (as are we), though fish are different in that their red blood cells contain nuclei (which ours don’t). This means that we can easily extract DNA from just a sample of their blood; this would not be nearly so easy using our blood. Below are just a few of the many red-blooded fishes here.
Additionally, many fishes down here are in the Nototheniidae family, and most of those also make antifreeze glycoproteins, or AFGPs. These proteins help to prevent the fish from freezing, as its name implies. Often we can determine the level of AFGP in a fish by analyzing its blood as well. However, at least two of the species have atypical AFGP production. One of them, Pleuragramma antarcticum, or the Antarctic silverfish, appears to only produce a limited selection of AFGP molecules, rather than the whole host of types. The other species of note is Lepidonotothen squamifrons, which appears to lack AFGP activity in its blood, yet still retains the AFGP gene (or something similar to it). My master’s thesis project is mostly focused on sequencing this genomic region to determine how it compares to the species with full AFGP activity. No pics of L. squamifrons to add yet, but check out the silverfish below.
There are also some cool fish down here known as the icefishes, of the family Channichthyidae. These fishes are so called because their blood is clear/white instead of red. This lack of color is due to their lack of hemoglobin, the iron-containing oxygen-binding molecule in our blood. A lot of interesting work has been done to study these fishes, though I myself have done little work on them (though taken lots of pictures)! Check out a few of them below.
Lastly, I’ll mention two of the other oddball species. One such fish is the snailfish, which has pink/translucent skin and a very jellylike, soft body. These are not very well studied, in part because they’re rarely caught. We were lucky enough to catch a handful in our trawls in the Gerlache Strait.