A Southern Ocean archipelago enhances feeding opportunities for a krill predator

Harrison, Lisa-Marie Katrina; Goetz, Kimberly T.; Cox, Martin J.; Harcourt, Robert

doi:10.1111/mms.12645

Cited by 6 publications

(2 citation statements)

References 78 publications

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“…Prior to this, the largest documented group size of feeding animals was 12 (Owen et al, 2015). This population is thought to feed predominantly on Antarctic krill ( Euphausia superba ; Groß et al, 2020; Harrison et al, 2020) in Antarctic waters (Franklin et al, 2012; Constantine et al, 2014; Harrison et al, 2020). However, these observations provide further evidence that extensive feeding occurs prior to leaving the coastal waters of Australia.…”

Section: Discussionmentioning

confidence: 99%

First evidence of bubble‐net feeding and the formation of ‘super‐groups’ by the east Australian population of humpback whales during their southward migration

Pirotta

Owen

Donnelly³

et al. 2021

Aquatic Conservation

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The recovery of overexploited populations is likely to reveal behaviours that may have been present prior to harvest but are only now reappearing as the population size increases. The east Australian humpback whale (Megaptera novaeangliae) population (group V, stock E1) has recovered well from past exploitation and is now estimated to be close to the pre‐whaling population size. Humpback whales were thought to follow a ‘feast and famine’ model historically, feeding intensively in high‐latitude feeding grounds and then fasting while migrating and in calving grounds; however, there is growing evidence that animals may feed outside of known foraging grounds. This short article reports on the first photographically documented evidence of bubble‐net feeding by humpback whales in Australian coastal waters (n = 10 groups observed) and provides the first evidence of a second site in the southern hemisphere for the formation of ‘super‐groups’ (n = 6 super‐groups at discrete locations). The formation of super‐groups may be linked to changes in the type or density of prey available, either along the migratory route or in the feeding grounds of the previous summer. It is also possible that the increased population size following recovery make large group sizes while feeding more common. These findings strongly support evidence that feeding behaviour is not restricted to high‐latitude foraging grounds in the Southern Ocean, and that prey consumption prior to leaving the coastal waters of Australia may be a significant component of the migratory ecology of this population. Understanding how environmental variation influences the extent to which humpback whales depend on foraging opportunities along their migratory route, and where feeding occurs, will help to predict how future changes in the ocean will influence whale populations. This will also allow for more effective management measures to reduce the impact of threats during this important period of energy consumption.

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Section: Discussionmentioning

confidence: 99%

First evidence of bubble‐net feeding and the formation of ‘super‐groups’ by the east Australian population of humpback whales during their southward migration

Pirotta

Owen

Donnelly³

et al. 2021

Aquatic Conservation

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“…a substantial biomass) (Reilly et al, 2004). Adopting an engulfmentfeeding strategy and consuming bulk quantities of krill during high velocity lunges (Goldbogen et al, 2013), baleen whales maximise efficiency by selectively targeting large/dense krill aggregations (Santora et al, 2010;Goldbogen et al, 2012;Miller et al, 2019;Harrison et al, 2020). In contrast, penguins forage on individual krill, even when foraging within a swarm (Watanabe et al, 2014), and require a much smaller energy load (total prey kg consumed).…”

Section: Penguin Foraging Strategiesmentioning

confidence: 99%

Spatial link between Adélie penguin foraging effort and krill swarm abundance and distribution

et al. 2023

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Understanding how predator foraging behaviour is influenced by the distribution and abundance of prey is a fundamental challenge in marine foraging ecology. This is particularly relevant in Southern Ocean ecosystems where the relationships between select predator species and Antarctic krill (Euphausia superba) can inform ecosystem conservation and precautionary fisheries management. In this study, we examine the spatial associations between krill swarm characteristics and Adélie penguin (Pygoscelis adeliae) foraging effort at Béchervaise Island, a long-term monitoring site in East Antarctica. Spatially integrating two years of regional-scale krill acoustic data with contemporaneous horizontal and vertical movement information from chick-rearing adult Adélie penguins, we assessed how penguin foraging effort changed in relation to krill swarm abundance and distribution across the survey area. Our findings show that penguin diving effort was focused in areas with a high number of krill swarms, yet they did not focus their effort in areas with high krill biomass. These results suggest the spatial organisation of Adélie penguin foraging effort can provide an indication of krill presence (and/or availability) but may not reflect krill abundance. We discuss our results in the context of penguin foraging strategies, capturing single krill within the water column rather than the engulfment feeding strategy of larger marine mammals such as whales. Our work substantially improves understanding of penguin-krill dynamics in East Antarctica and provides a greater level of nuance regarding the utility of Adélie penguins as indicator species under CCAMLR’s Ecosystem Monitoring Programme (CEMP). Understanding these predator-prey linkages will become increasingly important for managing any expanding krill fisheries in the region or changes in the prey field under future climate change scenarios. Thus, our results can be interpreted alongside other ecological indicators to support management of the East Antarctic sector of the Southern Ocean ecosystem.

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Ecological interactions between Antarctic krill (Euphausia superba) and baleen whales in the South Sandwich Islands region – Exploring predator-prey biomass ratios

Baines¹,

Jackson²,

Fielding³

et al. 2022

Deep Sea Research Part I: Oceanographic Research Papers

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A Southern Ocean archipelago enhances feeding opportunities for a krill predator

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Cited by 6 publications

References 78 publications

First evidence of bubble‐net feeding and the formation of ‘super‐groups’ by the east Australian population of humpback whales during their southward migration

First evidence of bubble‐net feeding and the formation of ‘super‐groups’ by the east Australian population of humpback whales during their southward migration

Spatial link between Adélie penguin foraging effort and krill swarm abundance and distribution

Ecological interactions between Antarctic krill (Euphausia superba) and baleen whales in the South Sandwich Islands region – Exploring predator-prey biomass ratios

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