Long-term monitoring of southern right whale feeding behavior indicates that Península Valdés is more than a calving ground

Foraging dives of southern right whales (Eubalaena australis) in relation to larger zooplankton size prey availability in Golfo Nuevo, Península Valdés, Argentina

“…Additionally, while surface photographs and video clips from aerial drones or underwater cameras have successfully captured behaviors at or just below the water surface in marine mammals (e.g. 15 – 17 ), these images are unable to document their deep-sea behavior. Fortunately, progress in imaging technology over the last three decades has led to the development of small, minimally invasive devices for animal-borne video, audio, and data-logging deployments, enabling thorough documentation of their behavior 18 , 19 .…”

“…The SRW has a circumpolar distribution in the Southern Hemisphere between 12°S and 65°S 24 , migrating annually between productive feeding and sheltered calving grounds. SRWs are filter-feeders, using their baleen to filter prey from dense patches of zooplankton (mainly copepods and euphausiids) 9 , 17 , 25 . Feeding typically occurs in austral summer and fall in regions located around 40°S and 65°S 26 – 29 .…”

“…Additionally, although it was previously believed that SRWs feed only in feeding grounds and not in calving grounds such as Península Valdés 54 , investigations have demonstrated that SRWs do feed in the gulfs off Península Valdés 7 , 13 , 55 . Furthermore, a recent study identified the waters off Península Valdés as a multi-use habitat for SRWs 17 . An analysis of photographic and video data from 2007 to 2019 conducted by D’Agostino et al 17 revealed that SRWs feed annually throughout the calving season at Península Valdés (June to December), primarily during the spring months.…”

“…Furthermore, a recent study identified the waters off Península Valdés as a multi-use habitat for SRWs 17 . An analysis of photographic and video data from 2007 to 2019 conducted by D’Agostino et al 17 revealed that SRWs feed annually throughout the calving season at Península Valdés (June to December), primarily during the spring months. Studies have demonstrated that at Península Valdés, SRWs mainly feed on adult and fifth copepodite (CV) stage of calanoid copepods ( Calanoides carinatus , Calanus australis , Ctenocalanus vanus , and Paracalanus parvus ), zoeae of squat lobster ( Grimothea gregaria ), calyptopis and furcilia of euphausiids ( Euphausia lucens ), as well as fish eggs and larvae 7 , 13 , 55 .…”

“…Studies have demonstrated that at Península Valdés, SRWs mainly feed on adult and fifth copepodite (CV) stage of calanoid copepods ( Calanoides carinatus , Calanus australis , Ctenocalanus vanus , and Paracalanus parvus ), zoeae of squat lobster ( Grimothea gregaria ), calyptopis and furcilia of euphausiids ( Euphausia lucens ), as well as fish eggs and larvae 7 , 13 , 55 . D’Agostino et al 17 observed SRWs feeding both at and below the surface (< 10 m) and suggested that SRWs dive to feed near the bottom, evidenced by observations of individuals surfacing with mud on their heads. However, to our knowledge, conclusive evidence of SRWs feeding near the bottom in Península Valdés is lacking.…”