Ocean warming threatens southern right whale population recovery

Agrelo, Macarena; Daura‐Jorge, Fábio G.; Rowntree, Victoria J.; Sironi, Mariano; Hammond, Philip S.; Ingram, Simon; Marón, Carina F.; Vilches, Florencia Ornela; Seger, Jon; Payne, Roger; Simões-Lopes, Paulo César

doi:10.1126/sciadv.abh2823

Cited by 21 publications

(25 citation statements)

References 56 publications

(77 reference statements)

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“…Broad climate events such as El Niño can affect the oceanic structure of the Southern Ocean. The Southern Ocean ecosystem relies heavily on phytoplankton and krill abundance for other species' survival, previously reported for Antarctic whales, King Penguins (Aptenodytes patagonicus), and SES (McIntyre et al 2014;Cristofari et al 2018;Bestley et al 2020;Rogers et al 2020;Agrelo et al 2021;Volzke et al 2021). Over the last four decades, the global SES population has seen dramatic declines in some populations due to the changes in food availability (McMahon et al 2005a;Volzke et al 2021).…”

Section: Population Declines Impacted By Climate Changementioning

confidence: 91%

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Chua

McMahon

et al. 2022

Polar Biol

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Marine animals such as the southern elephant seal (Mirounga leonina) rely on a productive marine environment and are vulnerable to oceanic changes that can affect their reproduction and survival rates. Davis Base, Antarctica, acts as a moulting site for southern elephant seals that forage in Prydz Bay, but the mitochondrial haplotype diversity and natal source populations of these seals have not been characterized. In this study, we combined genetic and animal tracking data on these moulting seals to identify levels of mitochondrial haplotype diversity, natal source population, and movement behaviours during foraging and haul-out periods. Using partial sequences of the mitochondrial control region, we identified two major breeding mitochondrial lineages of seals at Davis Base. We found that the majority of the seals originated from breeding stocks within the South Atlantic Ocean and South Indian Ocean. One seal was grouped with the Macquarie Island breeding stock (South Pacific Ocean). The Macquarie Island population, unlike the other two stocks, is decreasing in size. Tracking data revealed long-distance foraging activity of the Macquarie Island seal around Crozet Islands. We speculate that changes to the Antarctic marine environment can result in a shift in foraging and movement strategies, which subsequently affects seal population growth rates.

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Section: Population Declines Impacted By Climate Changementioning

confidence: 91%

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Chua

McMahon

et al. 2022

Polar Biol

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“…Different from New Zealand (Carroll et al, 2013), the fixed survival rate was not selected by the best‐fit model. In Argentina, there is a relationship among the survival rates of whales and ocean warming (Agrelo et al, 2021), and once the Brazilian breeding population has some relationship with Argentina, it is expected that a non‐fixed survival rate was observed here too. We do not test if there is some relationship between ocean warming and survival rates in Brazil, but oceanographic events like el Niño affect the reproductive success of right whales in Brazil (Seyboth et al, 2016).…”

Section: Discussionmentioning

confidence: 80%

How many are they? Estimates of demographic patterns of reproductive females of southern right whale (Eubalaena australis) in the southern coast of Brazil

2023

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Southern right whales use the Brazilian coast as a wintering area. This population was severely depleted by whaling up until 1973. Since the 1980s, studies have shown that this species is now restricted to the southern waters of Brazil. Using photoidentification data obtained via standardized aerial surveys from Florianópolis, State of Santa Catarina (SC) (−27.797°/−48.533°) to Torres, State of Rio Grande do Sul (RS) (−29.396°/−49.763°), mark-recapture methods were used to estimate survival capture and recruitment probability, population size using the POPAN model for reproductive females. Data were collected between 2004 and 2021. The final model was selected based on the lowest Akaike Information Criterion value. Of the 396 female whales identified, 41.41% were recaptured at least once. The final POPAN model showed time dependence in all parameters. The population size was estimated to be 397 reproductive females. This is the first update on the population trends for southern right whales in Brazilian breeding grounds since 2010.

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“…Such changes are not unique to South African waters, as in recent years, fluctuations in southern right whale counts 32 , elongation of calving intervals 32 , 70 , 71 and increased calf mortality 71 , 72 have been observed across several wintering grounds, with (at least) short-term effects on the population growth rate 73 , 74 . While certain discrepancies in changes between the different breeding populations exist, they all seem directly or indirectly related to altered prey availability 25 , 27 , 34 , 75 . The species can therefore represent a sentinel for environmental change in their South Ocean foraging grounds.…”

Section: Discussionmentioning

confidence: 99%

Decadal decline in maternal body condition of a Southern Ocean capital breeder

Vermeulen

Thavar

Glarou

et al. 2023

Sci Rep

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The changing physical properties of the Southern Ocean are known to impact the recruitment and survival of Antarctic krill (Euphausia superba). For oceanic krill predators, the resulting reduced energy intake may lead to population-level effects likely preceded by an alteration in the animals’ body condition. This is especially true for capital breeders that rely on stored energy for successful reproduction. One such Southern Ocean capital breeder, the southern right whale (Eubalaena australis), has been monitored over the past 43 years in their South African wintering ground. Changes in the population have been documented in the past decade, including a decreased reproductive rate and a shift in foraging strategy. To evaluate if a reduced foraging success is an underlying factor, we assessed the temporal variation in morphological body condition through aerial photogrammetry. Results showed a 23% reduction in maternal body condition, potentially contributing to the decreased reproductive rate of the population. To the best of our knowledge, this is the first study to quantify a decadal reduction in the body condition of a capital breeder dependent on Southern Ocean productivity. Understanding the bioenergetic consequences of environmental change is vital to predicting species’ resilience to climate change.

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Ocean warming threatens southern right whale population recovery

Cited by 21 publications

References 56 publications

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

Movements of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: combining population genetics and tracking data

How many are they? Estimates of demographic patterns of reproductive females of southern right whale (Eubalaena australis) in the southern coast of Brazil

Decadal decline in maternal body condition of a Southern Ocean capital breeder

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