Publication Date:
2024-02-14
Description:
A breeding colony of notothenioid icefish (Neopagetopsis ionah, Nybelin 1947) of globally unprecedented
extent has been discovered in the southern Weddell Sea, Antarctica. The colony was estimated to cover
at least �240 km2 of the eastern flank of the Filchner Trough, comprised of fish nests at a density of 0.26 nests
per square meter, representing an estimated total of �60 million active nests and associated fish biomass of
〉60,000 tonnes. The majority of nests were each occupied by 1 adult fish guarding 1,735 eggs (±433 SD). Bot-
tom water temperatures measured across the nesting colony were up to 2�C warmer than the surrounding
bottom waters, indicating a spatial correlation between the modified Warm Deep Water (mWDW) upflow
onto the Weddell Shelf and the active nesting area. Historical and concurrently collected seal movement
data indicate that this concentrated fish biomass may be utilized by predators such as Weddell seals (Lep-
tonychotes weddellii, Lesson 1826). Numerous degraded fish carcasses within and near the nesting colony
suggest that, in death as well as life, these fish provide input for local food webs and influence local biogeo-
chemical processing. To our knowledge, the area surveyed harbors the most spatially expansive continuous
fish breeding colony discovered to date globally at any depth, as well as an exceptionally high Antarctic sea-
floor biomass. This discovery provides support for the establishment of a regional marine protected area in
the Southern Ocean under the Convention on the Conservation of Antarctic Marine Living Resources
(CCAMLR) umbrella.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
peerRev
Format:
application/pdf
