Humpback whale (Megaptera novaeangliae) distribution and movements in the vicinity of South Georgia and the South Sandwich Islands Marine Protected Area

Southern right whales (Eubalaena australis) occur in the waters around the sub-Antarctic island of South Georgia, where they use the area to feed during the austral summer months (Jackson et al., 2020;Kennedy et al., 2020;Moore et al., 1999;Richardson et al., 2012). Although Antarctic krill (Euphausia superba) is known to be an important part of their diet, there have been few descriptions of southern right whale foraging behavior or prey (Argüelles

Section: Date Sighting Time Utc Sighting Time Local Local Time Sunset...mentioning

confidence: 97%

Observations of southern right whales (Eubalaena australis) surface feeding on krill in austral winter at South Georgia

Calderan

Dornan

Fielding

et al. 2023

“…Southern Ocean foraging humpback whales occur in high densities in coastal regions north of and/or in proximity (10s of km) of the ice edge (15% sea ice concentration), as well as select regions adjacent to sub‐Antarctic islands (e.g., South Georgia; Baines et al, 2021; Bamford et al, 2022; Bedriñana‐Romano et al, 2022; Herr et al, 2016; Reisinger et al, 2021; Riekkola et al, 2018; Thiele et al, 2004). The exception is in the Ross Sea (south of ≈70°S) where humpback whales are rarely sighted even in ice‐free areas, despite supporting high densities of Antarctic minke whales ( Balaenoptera bonaerensis ; Ainley et al, 2017, 2020; Branch, 2011; Constantine et al, 2014; Murase et al, 2013; Riekkola et al, 2018).…”

Section: Figurementioning

confidence: 99%

The most southerly occurrence of humpback whales in the western Weddell Sea

Henderson

Cheeseman

Curcio

et al. 2023

Globally, warming oceans are causing marine species to shift poleward (Melbourne-Thomas et al., 2022). The Antarctic Peninsula is a global hotspot for human-induced warming (Jones et al., 2019;Turner et al., 2020), evidenced by lessening sea ice conditions (Kumar et al., 2021), warming oceans, and the collapse of ice shelves (Etourneau et al., 2019). Warming is influencing the spatiotemporal occurrence of prey species such as Antarctic krill (Euphausia superba; Kawaguchi & Nicol, 2020), which is, in turn, influencing the foraging behaviors and demographic success of some Southern Ocean predators, e.g., crabeater seals (Erignathus barbatus; Hückstädt et al., 2020). For highly mobile marine predators, such as baleen whales, which are free from range restrictions faced by central place foragers (Orians, 1979), foraging is thought to be directly dictated by finding and accessing profitable prey patches, likely driven by the underlying environmental conditions (e.g., sea ice and chlorophyll concentrations; Bedriñana-Romano et al., 2022;Meynecke et al., 2021;Reisinger et al., 2021). There is some recent evidence that humpback whale (Megaptera novaeangliae) foraging activities have shifted southward in response to record lows in sea-ice extent and presumably spatial shifts in krill populations (

“…This may mean that when feeding at some locations around SG/IG, these two species are occupying different niche spaces, perhaps targeting different krill sizes, swarm types, or different prey (e.g., SRW may sometimes feed on copepods; Valenzuela et al, 2009). However, both species have annual bimodal peaks in sightings (in summer and winter), and a recent satellite tracking study also estimated concentrated habitat use in SG/IG coast waters by humpback whales in winter (Bamford et al, 2022), indicating the importance of SG/IG to both species across multiple seasons. The sighting pattern may reflect humpback and right whales migrating past western SG/IG enroute to/from other feeding areas, or spatial variation in their use of SG/IG habitat across the feeding season.…”

Section: Srw Habitat Use In Sg/igmentioning

confidence: 99%

Photo‐identification and satellite telemetry connect southern right whales from South Georgia Island (Islas Georgias del Sur) with multiple feeding and calving grounds in the southwest Atlantic

Kennedy,

Carroll,

Zerbini

et al. 2023

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.