Ecologists fear Antarctic krill crisis

Schiermeier, Quirin

doi:10.1038/467015a

Cited by 30 publications

(18 citation statements)

References 1 publication

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“…Recently, concern was expressed by several scientists about the future sustainability of krill harvesting under the cumulative pressure of climate change and fisheries (Jacquet et al 2010, Schiermeier 2010. Such concern has been initiated by reports of a .…”

Section: Introductionmentioning

confidence: 99%

Impact of climate change on Antarctic krill

Flores¹,

Atkinson²,

Kawaguchi³

et al. 2012

Mar. Ecol. Prog. Ser.

274

206

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International audienceAntarctic krill Euphausia superba (hereafter `krill') occur in regions undergoing rapid environmental change, particularly loss of winter sea ice. During recent years, harvesting of krill has in creased, possibly enhancing stress on krill and Antarctic ecosystems. Here we review the overall impact of climate change on krill and Antarctic ecosystems, discuss implications for an ecosystem-based fisheries management approach and identify critical knowledge gaps. Sea ice decline, ocean warming and other environmental stressors act in concert to modify the abundance, distribution and life cycle of krill. Although some of these changes can have positive effects on krill, their cumulative impact is most likely negative. Recruitment, driven largely by the winter survival of larval krill, is probably the population parameter most susceptible to climate change. Predicting changes to krill populations is urgent, because they will seriously impact Antarctic ecosystems. Such predictions, however, are complicated by an intense inter-annual variability in recruitment success and krill abundance. To improve the responsiveness of the ecosystem-based management approach adopted by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), critical knowledge gaps need to be filled. In addition to a better understanding of the factors influencing recruitment, management will require a better understanding of the resilience and the genetic plasticity of krill life stages, and a quantitative understanding of under-ice and benthic habitat use. Current precautionary management measures of CCAMLR should be maintained until a better understanding of these processes has been achieved. [GRAPHICS]

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Section: Introductionmentioning

confidence: 99%

Impact of climate change on Antarctic krill

Flores¹,

Atkinson²,

Kawaguchi³

et al. 2012

Mar. Ecol. Prog. Ser.

274

206

View full text Add to dashboard Cite

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“…Fisheries bycatch causes deaths of more than 650,000 marine mammals each year (5). Overfishing has depleted food supplies by reducing fish populations by 50-90%, and industrial-scale krill harvesting will likely further deplete food resources (6)(7)(8). In addition, polar oceans are warming at rates twice as fast as the global average (3); this has already altered whale migrations, reduced benthic prey populations, and caused declines in seals and polar bears (Ursus maritimus) whose lifestyles are dependent on sea ice (9).…”

mentioning

confidence: 99%

Drivers and hotspots of extinction risk in marine mammals

Davidson

Boyer²,

Kim³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

234

267

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The world's oceans are undergoing profound changes as a result of human activities. However, the consequences of escalating human impacts on marine mammal biodiversity remain poorly understood. The International Union for the Conservation of Nature (IUCN) identifies 25% of marine mammals as at risk of extinction, but the conservation status of nearly 40% of marine mammals remains unknown due to insufficient data. Predictive models of extinction risk are crucial to informing present and future conservation needs, yet such models have not been developed for marine mammals. In this paper, we: (i) used powerful machinelearning and spatial-modeling approaches to understand the intrinsic and extrinsic drivers of marine mammal extinction risk; (ii) used this information to predict risk across all marine mammals, including IUCN "Data Deficient" species; and (iii) conducted a spatially explicit assessment of these results to understand how risk is distributed across the world's oceans. Rate of offspring production was the most important predictor of risk. Additional predictors included taxonomic group, small geographic range area, and small social group size. Although the interaction of both intrinsic and extrinsic variables was important in predicting risk, overall, intrinsic traits were more important than extrinsic variables. In addition to the 32 species already on the IUCN Red List, our model identified 15 more species, suggesting that 37% of all marine mammals are at risk of extinction. Most at-risk species occur in coastal areas and in productive regions of the high seas. We identify 13 global hotspots of risk and show how they overlap with human impacts and Marine Protected Areas.International Union for the Conservation of Nature Red List | threatened and endangered species | life history | random forest models O ceans occupy 71% of the earth's surface and harbor much of its biodiversity. Despite the vast expanse of the oceans, no area remains unaffected by humans (1). Human activities are polluting, warming, and acidifying the oceans, melting sea ice, overharvesting fisheries, and altering entire food webs (1-4). Fisheries bycatch causes deaths of more than 650,000 marine mammals each year (5). Overfishing has depleted food supplies by reducing fish populations by 50-90%, and industrial-scale krill harvesting will likely further deplete food resources (6-8). In addition, polar oceans are warming at rates twice as fast as the global average (3); this has already altered whale migrations, reduced benthic prey populations, and caused declines in seals and polar bears (Ursus maritimus) whose lifestyles are dependent on sea ice (9). The International Union for the Conservation of Nature (IUCN) Red List currently classifies 25% (32 of 128 species) of marine mammals as threatened with extinction. Examination of the threats on the basis of the Red List shows that nearly half of all species are threatened by two or more human impacts, with pollution being the most pervasive, followed by fishing, invasive species, develop...

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“…At the same time, there is considerable concern regarding the potential impact of fisheries for krill and Antarctic toothfish on Antarctic megafauna (Ainley and Siniff 2009;Schiermeier 2010). While it was previously believed that removal of large whales produced a krill surplus, there is now considerable uncertainty regarding the magnitude of krill stocks and the sustainability of large-scale harvesting (Schiermeier 2010).…”

Section: Antarctic Megafauna Needs Sciencementioning

confidence: 99%

Antarctic Megafauna

Eisert¹

2015

Exploring the Last Continent

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The megafauna (Greek μεγα: great; Latin fauna: animal life) of Antarctica is defined by absence. Two classes of vertebrates, reptiles and amphibians, are missing from the continent and its surrounding waters, and Antarctica has lacked true land vertebrates since dinosaurs last roamed the continent in the late Cretaceous. The ocean is the foundation of all vertebrate life in Antarctica, and none of its native birds and mammals can survive permanently in the continent's frigid, white interior. Antarctic vertebrates are all classified as marine and ultimately derive their food from the sea. Unlike in much of the Arctic, the harsher climate of Antarctica does not allow for significant plant growth, and no vertebrate herbivores exist. Antarctica's long isolation from other landmasses has resulted in the absence of surface predators such as the polar fox Alopex lagopus or polar bear Ursus maritimus, an important distinction between Antarctic and Arctic habitats. Antarctica and the Southern Ocean present some of the most challenging environmental conditions on Earth, including extreme cold, wind, dryness, radical seasonal changes in photoperiod, and extensive ice cover. But Antarctica also offers tremendous opportunity because it is a continent free of terrestrial mammalian predators, and the Southern Ocean surrounding the Antarctic continent includes some of the most productive marine habitats in the world.

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Ecologists fear Antarctic krill crisis

Cited by 30 publications

References 1 publication

Impact of climate change on Antarctic krill

Impact of climate change on Antarctic krill

Drivers and hotspots of extinction risk in marine mammals

Antarctic Megafauna

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