First records of Chionodraco hamatus nesting at Silverfish Bay (Terra Nova Bay, Ross Sea)

Nests of the icefish Chionodraco hamatus were documented for the first time at about 500 m depth at Terra Nova Bay (Victoria Land, western Ross Sea), in an area included in the Antarctic Specially Protected Area (ASPA) No. 173 in a portion of the General Protection Zone of the largest marine protected area of the world established, the Ross Sea Region Marine Protected Area (RSRMPA).

Here we report on the observation of five nests of C. hamatus by remote underwater video systems in November 2021, during an Italian Antarctic expedition. The nests, made of gravel and small stones, were circular and bowl-shaped with a uniform diameter of ~ 30-40 cm. Nest building behaviour, with the icefish individual alternating radial turns in clockwise and counter-clockwise movements was also recorded in situ for the first time. Prior to present work, nest building behaviour for C. hamatus was observed only in the frame of aquarium experiments. If confirmed, the occurrence of an icefish nesting area in Silverfish Bay would further strengthen the ecological and scientific value of ASPA No.173. Documenting nesting icefish also reinforces the high ecological value of nearshore coastal areas in the RSRMPA, and provides an important focus for guiding future research and monitoring in the MPA.