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The sub-Antarctic waters of South Georgia Island (Islas Georgias del Sur, SG/IG) are a regularly visited feeding ground for southern right whales (Eubalaena australis, SRW) in the southwest Atlantic. Satellite telemetry and photo-identification records were compared to better understand the role of SG/IG in the SRW migratory network. We present the first insights from SRW satellite-tracked from the SG/IG feeding ground, habitat use patterns in the Scotia Arc, and movements to Antarctic habitats. Photo-identification comparisons to calving and feeding areas across the South Atlantic and a review of sightings of cetaceans reported from Bird Island (west of SG/IG) since 1979 illuminate long-term habitat use patterns in SG/IG. We present the first recorded migratory movement between SG/IG and multiple countries: Argentina, Uruguay, and Brazil. Photo-identification (1) linked SG/IG to a female SRW with a long-term sighting history in Brazil, and (2) provided the first match between SG/IG and the western Antarctic Peninsula, suggesting the latter could extend the feeding area for southwest Atlantic SRW. Satellite tracking and opportunistic sightings suggest that shelf and coastal waters west of SG/IG represent an important multi-season SRW feeding habitat and add to our overall understanding of habitats and ranges occupied by recovering southwest Atlantic SRW.

We present a genome assembly from a Melanostigma gelatinosum (the limp eelpout; Chordata; Actinopterygii; Perciformes; Zoarcidae). The genome sequence is 662.0 megabases in span. Most of the assembly is scaffolded into 24 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.83 kilobases in length.

We present a genome assembly from an individual Notothenia rossii (the marbled rockcod; Chordata; Actinopterygii; Perciformes; Nototheniidae). The genome sequence is 1,042.9 megabases in span. Most of the assembly is scaffolded into 12 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 21.68 kilobases in length. Gene annotation of this assembly on Ensembl identified 24,432 protein coding genes.

The South Sandwich Islands are an isolated, oceanic, volcanically formed archipelago in the Atlantic sector of the Southern Ocean. The complex bathymetry, coupled with the location in the marginal sea-ice zone and the relationship with the ACC makes the region both productive and biodiverse. Although remote, the region is not pristine and has been subject to historic exploitation of cetaceans and currently supports small, sustainably managed fisheries for two species of toothfish. This special issue brings together a suite of papers that further our knowledge of the region and will contribute to the next review of the South Georgia and South Sandwich Islands Marine Protected Area, which is due in 2023. The ten papers cover a broad range of subjects, adding to our knowledge of oceanography, pelagic and benthic ecology and of habitat use by mobile vertebrate predators such as cetaceans and penguins. Whilst the papers address some important knowledge gaps, they also highlight how little is known about this region and provide pointers to future research priorities.

Lanternfishes (Myctophidae) are one of the most species-rich families of mid-water fishes. They inhabit the mesopelagic zone, where physical barriers to dispersal and gene flow are permeable. Thus, modes of speciation that rely exclusively on geographical separation are potentially of less importance than those that rely more prominently on evolution of assortative mating through divergent habitat use and/or sexual signals, including visual signals from bioluminescent light organs. Here we used phylogenetic, ecological and morphological data to investigate the roles of geography, habitat use and lateral photophores in lanternfish speciation.