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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 17 (2001), S. 0 
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In conjunction with the International North Water Polynya Study (NOW) in northern Baffin Bay, we examined the diets of ringed seals (Phoca hispida)1 on the west (Grise Fiord, Nunavut) and east (Qaanaaq, Greenland) sides of the polynya, using conventional stomach content analysis, as well as inferences from stable isotope ratios in seal muscle. Between May and July 1998, stomach and muscle tissue samples were collected from 99 ringed seals taken near Grise Fiord and 100 taken near Qaanaaq. The amphipod Themisto libellula was the dominant prey type in the diet of immature ringed seals from Grise Fiord, whereas arctic cod (Boreogadus saida) and polar cod (Arctogadus glacialis) predominated in the diet of adults. Both immature and adult seals collected near Qaanaaq fed predominantly on arctic cod. Overall, seals collected near Grise Fiord had significantly higher δ13C values than those collected near Qaanaaq (P 〈 0.001), but there was no statistical separation in δ15N values between the two samples (P= 0.06). Differences in diets of ringed seals from the east and west sides of the North Water Polynya may be due to differences in prey distribution and/or differences in biological productivity and fish biomass within the polynya.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The impact of whole-lake lime (slaked lime, Ca(OH)2, and/or calcite, CaCO3) addition on plankton communities was evaluated in eutrophic hardwater lakes on the North American Boreal Plain.2. Two lakes received a single treatment of lime (Ca(OH)2 at 74 or 107 mg L–1), two lakes received multiple treatments with Ca(OH)2 and/or CaCO3 (5–78 mg L–1), and four lakes were untreated and served as reference systems.3. Over the long-term (〉 1 year), phytoplankton biomass was reduced in multiple-dose lakes, but not in single-dose lakes. Cyanobacteria typically dominated the algal community in the years before, during and after lime treatment in both single- and multiple-dose lakes.4. In the single-dose lakes, randomized intervention analysis showed no significant change in the biomass of zooplankton after lime addition.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Aquatic macrophytes are abundant in ponds and canals that are constructed in semi-arid regions for water storage and conveyance, as well as in lakes that are culturally enriched.2. Addition of Ca(OH)2 to two hardwater ponds at 250 or 275 mg L–1 caused an immediate eradication of submersed aquatic plants. Although these ponds are well-buffered (alkalinity: 2.57–3.94 mequiv L–1; pH: 8.1–9.0), lime addition caused an immediate increase in pH of 0.2–3 units.3. Application of 135 mg L–1 Ca(OH)2 for 24 h or 210 mg L–1 Ca(OH)2 for 65 h to two irrigation canals had no effect on macrophyte biomass at the lower concentration and duration, but resulted in the elimination of aquatic macrophytes 1 month after the higher concentration, longer duration treatment.4. Unlike the macrophyte control achieved following application of 210–275 mg L–1 Ca(OH)2 to ponds or canals, microcosm experiments in which lime formulation [slaked lime (Ca(OH)2), calcite (CaCO3), or a 1 : 1 mixture] and concentrations (up to 1500 mg L–1) were manipulated failed to elicit a consistent change in macrophyte biomass. Macrophytes in microcosms treated for the short-term (23–33 days) with ≥ 200 mg L–1 Ca(OH)2 or a mixed Ca(OH)2/CaCO3 formulation always lost pigmentation, but biomass was not consistently reduced.5. Declines in macrophyte biomass following treatment of ponds and canals may have been triggered by a short-term rise in pH which, in these relatively warm (22–23 °C) alkaline (2.28–3.94 mequiv L–1) systems, would have resulted in low concentrations of free CO2 and bicarbonate for photosynthesis.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2020-05-01
    Description: 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.
    Print ISSN: 0739-0572
    Electronic ISSN: 1520-0426
    Topics: Geography , Geosciences , Physics
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  • 5
  • 6
    Publication Date: 2020-07-07
    Description: 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
    Type: Article , isiRev
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  • 7
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    Unknown
    In:  EPIC322nd Biennial Society for Marine Mammalogy Conference on the Biology of Marine Mammals, Halifax, Nova Scotia, Canada, 2017-10-22-2017-10-27
    Publication Date: 2017-11-02
    Description: We are interested in making a comparison of three methods to detect marine mammals at sea offshore of Atlantic Canada: marine mammal observers (MMOs) making visual observations, MMOs assisted by a thermal-IR (infrared) automatic detection system, and passive acoustic monitoring (PAM). Prior to making this comparison, the detection and classification algorithms for the thermal-IR system required optimization for use in the thermal regime offshore Atlantic Canada. In summer 2015, we made visual observations concurrent with the collection of thermal-IR data at a shore-based observation site at Cape Race, Newfoundland. A total of 1114 location fixes on marine mammals were made using a theodolite: humpback whales (n = 967), minke whales (n = 112), harbour porpoises (n = 10), unidentified baleen whales (n = 16), and unidentified whales (n = 9). Thermal imagery data were retrospectively scanned and thermal anomalies that could be identified as marine mammals were found to match 700 of the 1114 fixes. Of the remaining 414 fixes, 366 were not found in the images, and 48 were undetermined. This dataset was used to optimize the detection and classification algorithms prior to the 2016 field season. In general, ≥70% of marine mammal sightings made by MMOs within 3 km of the shore-based observation site were discernible in thermal-IR imagery during periods when the Beaufort wind force was ≤ 6, for all sighting cues (e.g., blow, body) and species combined. The three detection methods will be compared during a research cruise in summer 2017. The results should be useful in the development of best practice guidelines for marine mammal mitigation monitoring during seismic surveys in Canada.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 8
    Publication Date: 2022-05-26
    Description: 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.
    Description: 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.
    Description: 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.
    Keywords: Ocean ; Instrumentation/sensors ; Remote sensing ; Animal studies ; Field experiments
    Repository Name: Woods Hole Open Access Server
    Type: Article
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