Aerial surveys for Antarctic minke whales ( Balaenoptera bonaerensis ) reveal sea ice dependent distribution patterns
| Autor: | S. Viquerat, Boris Dorschel, Ursula Siebert, Natalie Kelly, M. Scheidat, Linn Sophia Lehnert, Rob Williams, Karl-Hermann Kock, Helena Herr, Marcus Huntemann |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Aerial survey Antarctic minke whale distribution 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Abundance (ecology) lcsh:QH540-549.5 Sea ice Bathymetry 14. Life underwater marginal ice zone distance sampling Southern Ocean ship‐based helicopter surveys density surface models Sea ice concentration Ecology Evolution Behavior and Systematics southern ocean 030304 developmental biology Nature and Landscape Conservation 0303 health sciences geography Distance sampling geography.geographical_feature_category Ecology Business Manager projecten Midden-Noord ship-based helicopter surveys Generalized additive model Oceanography Balaenoptera bonaerensis Environmental science lcsh:Ecology Business Manager projects Mid-North |
| Zdroj: | Ecology and Evolution 9 (2019) 10 Ecology and Evolution, Vol 9, Iss 10, Pp 5664-5682 (2019) Ecology and Evolution, 9(10), 5664-5682 Ecology and evolution, 9(10):5664–5682 |
| ISSN: | 2045-7758 |
| DOI: | 10.1002/ece3.5149 |
| Popis: | This study investigates the distribution of Antarctic minke whales (AMW) in relation to sea ice concentration and variations therein. Information on AMW densities in the sea ice‐covered parts of the Southern Ocean is required to contextualize abundance estimates obtained from circumpolar shipboard surveys in open waters, suggesting a 30% decline in AMW abundance. Conventional line‐transect shipboard surveys for density estimation are impossible in ice‐covered regions, therefore we used icebreaker‐supported helicopter surveys to obtain information on AMW densities along gradients of 0%–100% of ice concentration. We conducted five helicopter surveys in the Southern Ocean, between 2006 and 2013. Distance sampling data, satellite‐derived sea‐ice data, and bathymetric parameters were used in generalized additive models (GAMs) to produce predictions on how the density of AMWs varied over space and time, and with environmental covariates. Ice concentration, distance to the ice edge and distance from the shelf break were found to describe the distribution of AMWs. Highest densities were predicted at the ice edge and through to medium ice concentrations. Medium densities were found up to 500 km into the ice edge in all concentrations of ice. Very low numbers of AMWs were found in the ice‐free waters of the West Antarctic Peninsula (WAP). A consistent relationship between AMW distribution and sea ice concentration weakens the support for the hypothesis that varying numbers of AMWs in ice‐covered waters were responsible for observed changes in estimated abundance. The potential decline in AMW abundance stresses the need for conservation measures and further studies into the AMW population status. Very low numbers of AMWs recorded in the ice‐free waters along the WAP support the hypothesis that this species is strongly dependent on sea ice and that forecasted sea ice changes have the potential of heavily impacting AMWs. |
| Databáze: | OpenAIRE |
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