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  • 1
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    Online Resource
    Summer Abundance of Harbour Porpoises (Phocoena phocoena) in the Coastal Waters of Iceland and the Faroe Islands
    UiT The Arctic University of Norway ; 2020
    In:  NAMMCO Scientific Publications Vol. 11 ( 2020-08-17)
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 11 ( 2020-08-17)
    Abstract: This study presents the first fully corrected abundance estimates for the harbour porpoise (Phocoena phocoena) for Iceland and the Faroe Islands. In both regions reliable estimates are needed to assess the impact of by-catch and other threats to harbour porpoises. Aerial surveys with harbour porpoise as a secondary and main target species were conducted in the summers of 2007 and 2010 in Icelandic and in Faroese coastal waters respectively. In Iceland, the cue counting procedure was used (which also produces the data required for line transect analysis), while in the Faroese, standard line transect sampling was applied, following the SCANS-II (Small Cetacean Abundance in the North Sea) survey protocol. In both surveys, identical aircraft surveyed at an altitude of 600 ft and a speed of 90–100 kn. Only data collected during Beaufort Sea States (BSS) lower than 3 and during good or moderate porpoise sighting conditions were used for abundance estimates. Abundance estimates were corrected using stratified estimates of esw (incorporating g(0)) values derived during the SCANS-II survey in 2005 as principal observers took part in this survey as well. In Iceland, realised effort in good or moderate harbour porpoise sighting conditions totalled 8,289 km in 13 survey strata, where 77 sightings (109 individuals) were made by the experienced harbour porpoise observer only. In Faroese waters, only part of the area inside the 300 m depth curve could be surveyed and 1,564 km were surveyed in good or moderate porpoise sighting conditions, yielding 39 sightings (49 individuals). The total abundance estimates were 43,179 porpoises (CV=0.45; 95% CI: 31,755–161,899) for Icelandic coastal waters and 5,175 porpoises (CV=0.44; 95% CI: 3,457–17,637) for Faroese waters.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.11
    DOI: 10.7557/3.4939
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2020
    detail.hit.zdb_id: 2736527-X
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  • 2
    Online Resource
    Online Resource
    Density surface fitting to estimate the abundance of humpback whales based on the NASS-95 and NASS- 2001 aerial and shipboard surveys
    UiT The Arctic University of Norway ; 2009
    In:  NAMMCO Scientific Publications Vol. 7 ( 2009-09-01), p. 143-
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 7 ( 2009-09-01), p. 143-
    Abstract: Generalized additive models (GAMs) with spatially referenced covariates were fitted to data collected during the 1995 and 2001 Icelandic (shipboard and aerial) and Faroese (shipboard only) components of the North Atlantic Sightings Surveys (NASS-95 and NASS-2001). The shipboard surveys extended from the east coast of Greenland, around Iceland, down to an area along the west coast ofIreland (in 1995) and to the north of the United Kingdom (in 2001). In contrast, the aerial surveys were limited to Icelandic coastal waters only. The aim of the analysis was to predict density, and hence abundance, of humpback whales throughout the survey regions and also to establish if there was any evidence that humpback whale density was related to sea surface temperature or depth.Fitting GAMs to the 1995 data proved problematic and so various subsets of the data were used in an attempt to improve the model fitting. Such difficulties did not occur with the 2001 data. Confidence intervals (CIs) for the abundance estimates were estimated using bootstrap sampling methods.The estimated humpback whale abundance for the region covered by the aerial and shipboard surveys in 1995 was 10,521 (95% CI: 3,716–24,636) using all available data and 7,625 (3,641–22,424) if survey blocks with 0 sightings around the Faroes and south of 60˚ N where no humpback whales were detected were excluded from the analysis. The estimate for the total survey region in 2001 was 14,662 (9,441–29,879). The high upper bounds of the confidence intervals were thought to be caused by a paucity of effort over wide areas of the survey leading to interpolation. Overall, the uncertainty associated with these abundance estimates was approximately equal to, or greater than, that associated with a stratified distance analysis. Given these wide CIs the evidence for a substantial difference in abundance between years was equivocal. However there was evidence to suggest that humpback whales congregated in shallower waters between 6–8˚C.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.7
    DOI: 10.7557/3.2711
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2009
    detail.hit.zdb_id: 2736527-X
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  • 3
    Online Resource
    Online Resource
    Oceanic Drivers of Sei Whale Distribution in the North Atlantic
    UiT The Arctic University of Norway ; 2020
    In:  NAMMCO Scientific Publications Vol. 11 ( 2020-05-06)
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 11 ( 2020-05-06)
    Abstract: This study investigated the oceanic drivers of sei whale (Balaenoptera borealis) distribution in the central and eastern North Atlantic, and explored how distribution may have changed over almost three decades. Cetacean sightings data were available from Icelandic, Faroese and Norwegian surveys conducted throughout the central and eastern North Atlantic during summer between 1987 and 2015. Effective strip half width was estimated from the data to take account of variation in detection probability. Spatially-referenced environmental variables used as predictors in generalised additive models of sei whale relative density included: relief-related variables seabed depth, slope and aspect; monthly-varying physical oceanographic variables sea surface temperature (SST), mixed layer depth, bottom temperature, salinity, and sea surface height anomaly (SSH); and monthly-varying biological oceanographic variables chlorophyll-a concentration and primary productivity. Preliminary analysis considered which month (March-August) in the dynamic oceanographic variables explained most variability in sei whale density. Models including all variables (“full models”) could only be run for 1998-2015 because data for several variables were missing in earlier years. “Simple models" including only relief-related variables and SST were therefore run for 1987-89, and also for 1998-2015 for comparison. The best-fitting full model for 1998-2015 retained the covariates depth, May SST, May bottom temperature, July salinity, July SSH and July primary productivity. Of these, depth, May SST and July SSH were the strongest predictors of sei whale density. In the simple models for both 1987-89 and 1998-2015, depth (especially), May SST and seabed slope were the strongest predictors of sei whale density. The highest densities of sei whales were predicted in the Irminger Sea and over the Charles-Gibbs Fracture Zone; a pattern driven by large negative SSH, deep water ( 〉 1500m) and polar-temperate SST (5-12oC). There was some inter-annual variability in predicted distribution and there appears to be a northward expansion in distribution consistent with prey species responding to ocean warming. The models could be used to predict future distribution of sei whales based on future environmental conditions predicted by climate models.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.11
    DOI: 10.7557/3.5211
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2020
    detail.hit.zdb_id: 2736527-X
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  • 4
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    Online Resource
    Trends in the distribution and abundance of cetaceans from aerial surveys in Icelandic coastal waters, 1986-2001
    UiT The Arctic University of Norway ; 2009
    In:  NAMMCO Scientific Publications Vol. 7 ( 2009-09-01), p. 117-
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 7 ( 2009-09-01), p. 117-
    Abstract: Aerial surveys were carried out in coastal Icelandic waters 4 times between 1986 and 2001 as part of the North Atlantic Sightings Surveys. The surveys had nearly identical designs in 3 of the 4 years. The target species was the minke whale (Balaenoptera acutorostrata) but all species encountered were recorded. Sighting rate and density from line transect analysis were used as indices of relative abundance to monitor trends over the period, and abundance estimates corrected for perception biases were calculated for some species from the 2001 survey. More than 11 species were sighted, of which the most common were the minke whale, humpback whale (Megaptera novaeangliae), dolphins of genus Lagenorhychus, and the harbour porpoise (Phocoena phocoena). Minke whales anddolphins showed little change in distribution or abundance over the period. There were an estimated 31,653 (cv 0.30) dolphins in the survey area in 2001. Humpback whales increased rapidly at a rate of about 12%, with much of the increase occurring off eastern and northeastern Iceland. In 2001 there were an estimated 4,928 (cv 0.463) humpback whales in the survey area. The relative abundance of harbour porpoises decreased over the period, but estimates for this species were compromised by uncorrected perception biases and poor coverage. The ecological and historical significance of these findings with respect to previous whaling activities and present-day fisheries is discussed.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.7
    DOI: 10.7557/3.2710
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2009
    detail.hit.zdb_id: 2736527-X
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  • 5
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    Distribution and Abundance of Killer Whales in the Central North Atlantic, 1987-2015
    UiT The Arctic University of Norway ; 2020
    In:  NAMMCO Scientific Publications Vol. 11 ( 2020-12-03)
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 11 ( 2020-12-03)
    Abstract: The North Atlantic Sightings Surveys (NASS), covering a large but variable portion of the Central and Eastern North Atlantic, were conducted in 1987, 1989, 1995, 2001, 2007 and 2015. Sightings of killer whales (Orcinus orca), a non-target species, were relatively rare in the Central Atlantic (Icelandic and Faroese) portions of the survey area. In cases where sighting numbers were insufficient, we pooled sightings over several surveys to derive a distance detection function and used this to estimate abundance using standard Distance Sampling methodology. Uncorrected estimates were produced for all surveys, and estimates corrected for perception bias were produced for the 2001 and 2015 surveys. Killer whales were sighted in all areas but were most common in the eastern part of the survey area. Uncorrected abundance in the NASS core area ranged from a low of 4,736 (95% CI: 1,842–12,176) in 1995 to a maximum of 15,142 (95% CI: 6,003–38,190) in 2001. The low precision of the estimates makes the detection of temporal trends unlikely. In 2007 an extension survey revealed relatively high numbers of killer whales to the east of the survey area, in conformity with Norwegian survey estimates in this area. The NASS and other surveys conducted over the period indicate that killer whales number in the low tens of thousands in the Central and Eastern North Atlantic.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.11
    DOI: 10.7557/3.5579
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2020
    detail.hit.zdb_id: 2736527-X
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  • 6
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    Online Resource
    Some Catch-at-Age Analysis Methods and Models Compared on Simulated Data
    Scientific Research Publishing, Inc. ; 2012
    In:  Open Journal of Marine Science Vol. 02, No. 01 ( 2012), p. 16-24
    Details
    In: Open Journal of Marine Science, Scientific Research Publishing, Inc., Vol. 02, No. 01 ( 2012), p. 16-24
    Type of Medium: Online Resource
    ISSN: 2161-7384 , 2161-7392
    URL: Article
    DOI: 10.4236/ojms.2012.21003
    Language: Unknown
    Publisher: Scientific Research Publishing, Inc.
    Publication Date: 2012
    detail.hit.zdb_id: 2631409-5
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  • 7
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    Online Resource
    Marine mammal consumption and fisheries removals in the Nordic and Barents Seas
    Oxford University Press (OUP) ; 2022
    In:  ICES Journal of Marine Science Vol. 79, No. 5 ( 2022-06-29), p. 1583-1603
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 79, No. 5 ( 2022-06-29), p. 1583-1603
    Abstract: In this study, we assess prey consumption by the marine mammal community in the northeast Atlantic [including 21 taxa, across three regions: (I) the Icelandic shelf, Denmark Strait, and Iceland Sea (ICE); (II) the Greenland and Norwegian Seas (GN); and (III) the Barents Sea (BS)], and compare mammal requirements with removals by fisheries. To determine prey needs, estimates of energetic requirements were combined with diet and abundance information for parameterizing simple allometric scaling models, taking uncertainties into account through bootstrapping procedures. In total, marine mammals in the ICE, GN, and BS consumed 13.4 [Confidence Interval (CI): 5.6–25.0] , 4.6 (CI: 1.9–8.6), and 7.1 (CI: 2.8–13.8) million tonnes of prey year–1. Fisheries removed 1.55, 1.45, and 1.16 million tonnes year–1 from these three areas, respectively. While fisheries generally operate at significantly higher trophic levels than marine mammals, we find that the potential for direct competition between marine mammals and fisheries is strongest in the GN and weakest in the BS. Furthermore, our results also demonstrate significant changes in mammal consumption compared to previous and more focused studies over the last decades. These changes likely reflect both ongoing population recoveries from historic whaling and the current rapid physical and biological changes of these high-latitude systems. We argue that changing distributions and abundances of mammals should be considered when establishing fisheries harvesting strategies, to ensure effective fisheries management and good conservation practices of top predators in such rapidly changing systems.
    Type of Medium: Online Resource
    ISSN: 1054-3139 , 1095-9289
    URL: Article
    DOI: 10.1093/icesjms/fsac096
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2463178-4
    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
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  • 8
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    Online Resource
    Spatial and temporal variation in body mass and the blubber, muscle and visceral fat content of North Atlantic common minke whales
    International Whaling Commission ; 2020
    In:  IWC Journal of Cetacean Research and Management Vol. 21, No. 1 ( 2020-09-11), p. 59-70
    Details
    In: IWC Journal of Cetacean Research and Management, International Whaling Commission, Vol. 21, No. 1 ( 2020-09-11), p. 59-70
    Abstract: The exponent for predicting total body mass from length has been studied in many species and here data on common minke whales from areas in the North Atlantic is added from both Icelandic and Norwegian research catches. The exponent was found to be not significantly different from 3. In addition seasonal changes in body mass and in the parts of blubber, muscle and visceral fat are reported. The exponent for how blubber mass increases with length is lower than 3. In all cases a significant increase over the season was detected, in particular for the mature animals, and also in girth measurements, particularly at the posterior part of the body. Pregnant females had significantly more blubber than other whales. These results agree with studies on blubber thickness measurements and tissue energy content of Icelandic baleen whales and observed changes in the ecosystem around Iceland during the research period.
    Type of Medium: Online Resource
    ISSN: 2312-2706 , 1561-0713
    URL: Issue
    URL: Article
    DOI: 10.47536/jcrm.v21i1
    DOI: 10.47536/jcrm.v21i1.150
    Language: Unknown
    Publisher: International Whaling Commission
    Publication Date: 2020
    detail.hit.zdb_id: 2744616-5
    SSG: 21,3
    SSG: 12
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  • 9
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    Online Resource
    Distribution, abundance, and feeding ecology of baleen whales in Icelandic waters: have recent environmental changes had an effect?
    Frontiers Media SA ; 2015
    In:  Frontiers in Ecology and Evolution Vol. 3 ( 2015-02-17)
    Details
    In: Frontiers in Ecology and Evolution, Frontiers Media SA, Vol. 3 ( 2015-02-17)
    Type of Medium: Online Resource
    ISSN: 2296-701X
    URL: Article
    DOI: 10.3389/fevo.2015.00006
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2015
    detail.hit.zdb_id: 2745634-1
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  • 10
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    Combined line-transect and cue-count estimate of sperm whale abundance in the North Atlantic, from Icelandic NASS-2001 shipboard survey
    UiT The Arctic University of Norway ; 2009
    In:  NAMMCO Scientific Publications Vol. 7 ( 2009-09-01), p. 73-
    Details
    In: NAMMCO Scientific Publications, UiT The Arctic University of Norway, Vol. 7 ( 2009-09-01), p. 73-
    Abstract: Sperm whales (Physeter macrocephalus) pose a particular problem to shipboard surveys as they dive for extended periods and are therefore likely to be missed (not available) even if they are right under the track line. To address these problems the NAMMCO planning committee for the NASS 2001 survey drew up guidelines to be followed when sperm whales were sighted. This required every deep dive to be recorded and considered to be a cue, from which a cue-count estimate is calculated if the cue rate is known. For those whales that did not dive before coming abeam, a conventional line-transect estimate is calculated, which gives an instantaneous surface estimate from which a total estimate can be obtained if the proportion of the time spent at the surface is known. These estimates are compared and combined. Precise dive cycle information is missing for the mostly single all male sperm whales in this area but a preliminary estimate of 11,185 (cv 0.34) is obtained for the surveyed area with an assumed surface time of 20% and two deep dives per hour.
    Type of Medium: Online Resource
    ISSN: 2309-2491 , 1560-2206
    URL: Issue
    URL: Article
    DOI: 10.7557/3.7
    DOI: 10.7557/3.2706
    Language: Unknown
    Publisher: UiT The Arctic University of Norway
    Publication Date: 2009
    detail.hit.zdb_id: 2736527-X
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