Spatial distribution of seals in the wider Weddell Sea (Antarctica) with links to ArcGIS map packages


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hendrik.pehlke [ at ] awi.de

Abstract

Here we provide two ArcGIS map packages with georeferenced files on the spatial distribution of seals in the wider Weddell Sea (Antarctica), which were created in the context of the development of a marine protected area in the Weddell Sea. Spatial distribution of seals based on aerial surveys: The map of the spatial distribution of crabeater seals is based on modelled seal abundances from Flores et al. (2008) and Forcada et al. (2012). These modelled abundances were supplemented by abundance data derived from Bester et al. (1995, 2002) and by point data from Pl\"otz et al. (2011a-e), which were translated into abundance values by the count method for line transect data. The calculated data on seal abundances from Pl\"otz et al. (2011a-e) and Bester et al. (1995, 2002) were interpolated using the inverse distance weighted method. The combined data set of modelled and interpolated abundances showed highest absolute seal abundances offshore the Riiser-Larsen Ice Shelf and Quarisen Ice Shelf. Spatial distribution of seals based on tracking data: The map of probability of seal occurrence is based on all tracking data publicly available for the wider Weddell Sea from the MEOP data portal "Marine Mammals Exploring the Oceans Pole to Pole" (data request: 14-11-2016). In addition, we have used MEOP data (UK data: ct27, ct70; German data: ct113, wd06, wd07) for which unconditional sharing is not yet accepted. These data were provided by Lars Boehme (University of St. Andrews) and Horst Bornemann (AWI), respectively. Furthermore, the data from the MEOP data portal were complemented by tracking data sets on southern elephant seals (Tosh et al. 2009, James et al. 2012), Weddell seals (McIntyre et al. 2013) and crabeater seals (Nachtsheim et al. 2016). All tracking data united were processed with a state-space model described by Johnson et al. (2008) and were implemented in the R package crawl (Johnson 2011). The tracking data analysis indicated frequent occurrence of seals in a larger area off the Brunt and Filchner Ice Shelf (approx. 25°W-40°W), and in smaller patches along the eastern Weddell Sea ice shelfs as well as in the region around the tip of the Antarctic Peninsula. More information on the spatial analysis is given in working paper WG-EMM-16/03 and WG-SAM-17/30 submitted to the CCAMLR Working Group on Ecosystem Monitoring and Management (EMM) and the CCAMLR Working Group on Statistics, Assessments and Modelling (SAM), respectively (available at https://www.ccamlr.org/en/wg-emm-16 and https://www.ccamlr.org/en/wg-sam-17



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Other
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Helmholtz Cross Cutting Activity (2021-2027)
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Published
Eprint ID
56957
DOI 10.1594/PANGAEA.899619

Cite as
Pehlke, H. , Brey, T. and Teschke, K. (2019): Spatial distribution of seals in the wider Weddell Sea (Antarctica) with links to ArcGIS map packages , [Other] doi: 10.1594/PANGAEA.899619


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