[5] P. walkeri live in the benthic zone of the Southern Ocean, all around Antarctica, down to a depth of 310 metres (1,020 ft).

[8] As omnivores, they eat phytoplankton, cryophilic flora, and Diphyllobothrium tapeworms, among other organisms, under the top level of ice.

[9] Predators include Trematomus borchgrevinki, T. newnesii, T. bernacchii, Notothenia corriiceps neglecta, and Adélie penguins.

[4] During a female's second (occasionally third) winter, she releases pheromones, picked up by a male's antennae, signaling that readiness to mate.

[3][7] When the sea water becomes diluted, the eggs may swell up, to keep the total salinity around the embryos constant.