GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1
    Publikationsdatum: 2020-07-07
    Beschreibung: Marine mammals are under growing pressure as anthropogenic use of the ocean increases. Ship strikes of large whales and loud underwater sound sources including air guns for marine geophysical prospecting and naval midfrequency sonar are criticized for their possible negative effects on marine mammals. Competent authorities regularly require the implementation of mitigation measures, including vessel speed reductions or shutdown of acoustic sources if marine mammals are sighted in sensitive areas or in predefined exclusion zones around a vessel. To ensure successful mitigation, reliable at-sea detection of animals is crucial. To date, ship-based marine mammal observers are the most commonly implemented detection method; however, thermal (IR) imaging–based automatic detection systems have been used in recent years. This study evaluates thermal imaging–based automatic whale detection technology for its use across different oceans. The performance of this technology is characterized with respect to environmental conditions, and an automatic detection algorithm for whale blows is presented. The technology can detect whales in polar, temperate, and subtropical ocean regimes over distances of up to several kilometers and outperforms marine mammal observers in the number of whales detected. These results show that thermal imaging technology can be used to assist in providing protection for marine mammals against ship strike and acoustic impact across the world’s oceans.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Publikationsdatum: 2016-11-25
    Beschreibung: Thermographic imaging has been shown to reliably detect marine mammals, both day and night, for operational mitigation in polar and subpolar waters (Zitterbart et al., 2013), with encouraging findings having recently been reported for temperate waters (NOAA Southwest Fisheries Science Center, 2015). As thermographic imaging is based on thermal contrast between whale body or blow and the sea surface, thermographic discriminability is expected to wane with increasing sea surface temperatures. ETAW explored the upper sea surface temperature limit of this approach by deploying high-end thermal cameras on North Stradbroke Island, Queensland, Australia (subtropical conditions) and on both the North and South shore of Kauai, HI, USA (tropical conditions). The study design included both acquisition of thermographic video as well as concurrent visual sightings, including double-blind setups. Our findings show, that cues of humpback whales are thermally discriminable even under the highest sea surface temperatures encountered (26°C / 79°F). Thermal discriminability and performance of computer based automatic detection of cues, appear, as based on the (subjective) experience gained in the field, to be more dependent on covariates such as camera height, sea-state and glare than on sea surface temperature. While increasing sea surface temperatures appear to reduce the operational radius of thermographic images (yet not below typical mitigation radii of 1-3 km), they did not render cues entirely indistinguishable from the background image, while glare and increased sea states caused increased numbers of false alerts. Comparisons of different IR technologies (scanning LWIR 8 – 12µm, focal plane array LWIR 8.0 – 9.4µm, focal plane array MWIR 3.7 – 5.5µm) suggest that the broadband LWIR sensor produced the clearest image least affected by glare. Tests of polarization filters in different orientations revealed that glare is somewhat, but not significantly reduced, for horizontal polarization orientation, but that benefits are outweighed by image degeneration due to the additional optics, at least for the high temperature resolution required in this application.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Conference , notRev
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    facet.materialart.
    Unbekannt
    Internatonal Whaling Commission
    In:  EPIC3The International Whaling Commission's 64th Annual Meeting, Panama City, Panama, 2012-06-11-2012-07-06The International Whaling Commission's 64th, Internatonal Whaling Commission, 6 p.
    Publikationsdatum: 2019-07-17
    Beschreibung: From 13 March to 09 April 2012 Germany conducted a fisheries survey on board RV Polarstern in the Scotia Sea (Elephant Island - South Shetland Island - Joinville Island area) under the auspices of CCAMLR. During this expedition, ANT-XXVIII/4, an opportunistic marine mammal survey was carried out. Data were collected for 26 days along the externally preset cruise track, resulting in 295 hrs on effort. Within the study area 248 sightings were collected, including three different species of baleen whales (fin whale (Balaenoptera physalus), humpback whale (Megaptera novaeangliae), and Antarctic minke whale (Balaenoptera bonaerensis) and one toothed whale species, killer whale (Orcinus orca). More than 62% of the sightings recorded were fin whales (155 sightings) which were mainly related to the Elephant Island area (116 sightings). Usual group sizes of the total fin whale sightings ranged from one to five individuals, also including young animals associated with adults during some encounters. Larger groups of more than 20 whales, and on two occasions more than 100 indivuduals, were observed as well. These large pods of fin whales were observed feeding in shallow waters (〈 300 m) on the north-western shelf off Elephant Island, concordant with large aggregations of Antarctic krill (Euphausia superba). This observation suggests that Elephant Island constitutes an important feeding area for fin whales in early austral fall, with possible implications regarding the regulation of (krill) fisheries in this area.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Miscellaneous , notRev
    Format: application/pdf
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of the Atmospheric and Oceanic Technology 37(5), (2020): 807-824, doi:10.1175/JTECH-D-19-0054.1.
    Beschreibung: Marine mammals are under growing pressure as anthropogenic use of the ocean increases. Ship strikes of large whales and loud underwater sound sources including air guns for marine geophysical prospecting and naval midfrequency sonar are criticized for their possible negative effects on marine mammals. Competent authorities regularly require the implementation of mitigation measures, including vessel speed reductions or shutdown of acoustic sources if marine mammals are sighted in sensitive areas or in predefined exclusion zones around a vessel. To ensure successful mitigation, reliable at-sea detection of animals is crucial. To date, ship-based marine mammal observers are the most commonly implemented detection method; however, thermal (IR) imaging–based automatic detection systems have been used in recent years. This study evaluates thermal imaging–based automatic whale detection technology for its use across different oceans. The performance of this technology is characterized with respect to environmental conditions, and an automatic detection algorithm for whale blows is presented. The technology can detect whales in polar, temperate, and subtropical ocean regimes over distances of up to several kilometers and outperforms marine mammal observers in the number of whales detected. These results show that thermal imaging technology can be used to assist in providing protection for marine mammals against ship strike and acoustic impact across the world’s oceans.
    Beschreibung: This work was funded by the Office of Naval Research (ONR) under Award N000141310856, by the Environmental Studies Research Fund (ESRF; esrfunds.org) under Award 2014-03S and by the Alfred-Wegener-Institute Helmholtz Zentrum für Polar- und Meeresforschung. DPZ and OB declare competing financial interests: 1) Patent US8941728B2, DE102011114084B4: A method for automatic real-time marine mammal detection. The patent describes the ideas basic to the automatic whale detection software as used to acquire and process the data presented in this paper. 2) Licensing of the Tashtego automatic whale detection software to the manufacturer of IR sensor. The authors confirm that these competing financial interests did not alter their adherence good scientific practice. We thank P. Abgrall, J. Coffey, K. Keats, B. Mactavish, V. Moulton, and S. Penney-Belbin for data collection or IR image review. We thank S. Besaw, J. Christian, A. Coombs, P. Coombs, W. Costello, T. Elliott, E. Evans, I. Goudie, C. Jones, K. Knowles, R. Martin, A. Murphy, D. and J. Shepherd; and the staffs at the Irish Loop Express, the Myrick Wireless Interpretive Centre, the Mistaken Point Ecological Reserve, and the lighthouse keepers for logistical assistance at our remote field site. We thank D. Boutilier and B. McDonald (DFO) for assisting us in obtaining license to occupy permits for Cape Race. We thank D. Taylor (ESRF Research Manager) for his support.
    Schlagwort(e): Ocean ; Instrumentation/sensors ; Remote sensing ; Animal studies ; Field experiments
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...