Responses of Antarctic pack-ice seals to environmental change and increasing krill fishing

The compound effects of changing habitats, ecosystem interactions, and fishing practices have implications for the management of Antarctic krill and conservation of its predators. For Antarctic pack-ice seals, an important group of krill predators, we estimate the density and krill consumption in th...

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Bibliographic Details
Published in:Biological Conservation
Main Authors: Forcada, Jaume, Trathan, Philip N., Boveng, Peter L., Boyd, Ian L., Burns, Jennifer M., Costa, Daniel P., Fedak, Michael, Rogers, Tracey L., Southwell, Colin J.
Format: Article in Journal/Newspaper
Language:unknown
Published: Elsevier 2012
Subjects:
Antarctic
Antarctic Peninsula
Marguerite
Marguerite Bay
The Antarctic
Weddell
Weddell Sea
Antarc*
Antarctic Krill
Crabeater Seals
Sea ice
Online Access:http://nora.nerc.ac.uk/id/eprint/16599/
http://www.sciencedirect.com/science/article/pii/S0006320712000948
Description
Summary:The compound effects of changing habitats, ecosystem interactions, and fishing practices have implications for the management of Antarctic krill and conservation of its predators. For Antarctic pack-ice seals, an important group of krill predators, we estimate the density and krill consumption in the West Antarctic Peninsula (WAP)–Western Weddell Sea area, the main fishery region; and we consider long-term changes in suitable pack-ice habitat, increased fishing pressure and potential krill declines based upon predictions from declines in sea ice cover. More than 3 million crabeater seals consumed over 12 million tonnes of krill each year. This was approximately 17% of the krill standing stock. The highest densities of pack ice seals where found in the WAP, including in its small-scale fishery management areas, where apparently suitable seal habitat has declined by 21–28% over a 30 year period, where krill density is likely to have declined, and fishing has increased. The highest seal density was found in the Marguerite Bay area which is a source of krill for the Antarctic Peninsula and elsewhere. Significant sea-ice loss since 1979 has already occurred, leading to open water and possible expansion for the fishery in the future. These factors may combine to potentially reduce food for pack ice seals. Therefore, high uncertainty in krill and seal stock trends and in their environmental drivers call for a precautionary management of the krill fishery, in the absence of survey data to support management based on specific conservation objectives for pack-ice seals.

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