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Ivar Christensen - One of the best experts on this subject based on the ideXlab platform.
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the northern bottlenose whale in the faroe islands 1584 1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
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The northern bottlenose whale in the Faroe Islands, 1584‐1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
Dorete Bloch - One of the best experts on this subject based on the ideXlab platform.
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the northern bottlenose whale in the faroe islands 1584 1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
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The northern bottlenose whale in the Faroe Islands, 1584‐1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
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Variation in foetal and postnatal sex ratios in long-finned pilot whales
Ophelia, 1994Co-Authors: Geneviève Desportes, Liselotte Wesley Andersen, Dorete BlochAbstract:Abstract Variation in foetal and postnatal sex ratios was examined jointly with the 1986-1988 Faroese international research programme on the ecology and status of the long-finned pilot whale (Globicephala melas). Data were obtained from 58 schools of whales landed in the Faroe Islands from 1958 to 1992. The sample includes 505 embryos and foetuses. Variation in foetal sex ratios was analysed according to gestational age, mother's age and years. Foetal and postnatal sex ratios from pilot whales off the Faroe Islands also were compared with those obtained off Newfoundland by Sergeant (1962). The overall foetal sex ratio was biased significantly towards more females than males. The proportion of male foetuses declined as the size of foetuses increased. Females older than 25 yrs of age in comparison to younger females bore more female than male foetuses. From birth, through the three first years oflife, selection acted mainly against females and parity was observed again in the age group 3 and maintained unt...
G. Desportes - One of the best experts on this subject based on the ideXlab platform.
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the northern bottlenose whale in the faroe islands 1584 1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
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The northern bottlenose whale in the Faroe Islands, 1584‐1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
M Zachariassen - One of the best experts on this subject based on the ideXlab platform.
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the northern bottlenose whale in the faroe islands 1584 1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
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The northern bottlenose whale in the Faroe Islands, 1584‐1993
Journal of Zoology, 1996Co-Authors: Dorete Bloch, M Zachariassen, G. Desportes, Ivar ChristensenAbstract:The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
B. Hansen - One of the best experts on this subject based on the ideXlab platform.
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Atlantic water flow through the Faroese Channels
Copernicus Publications, 2017Co-Authors: B. Hansen, T. Poulsen, K. Húsgarð M. Larsen, H. Hátún, S. Østerhus, E. Darelius, B. Berx, D. Quadfasel, K. JochumsenAbstract:Through the Faroese Channels – the collective name for a system of channels linking the Faroe–Shetland Channel, Wyville Thomson Basin, and Faroe Bank Channel – there is a deep flow of cold waters from Arctic regions that exit the system as overflow through the Faroe Bank Channel and across the Wyville Thomson Ridge. The upper layers, in contrast, are dominated by warm, saline water masses from the southwest, termed Atlantic water. In spite of intensive research over more than a century, there are still open questions on the passage of these waters through the system with conflicting views in recent literature. Of special note is the suggestion that there is a flow of Atlantic water from the Faroe–Shetland Channel through the Faroe Bank Channel, which circles the Faroes over the slope region in a clockwise direction. Here, we combine the observational evidence from ship-borne hydrography, moored current measurements, surface drifter tracks, and satellite altimetry to address these questions and propose a general scheme for the Atlantic water flow through this channel system. We find no evidence for a continuous flow of Atlantic water from the Faroe–Shetland Channel to the Faroe Bank Channel over the Faroese slope. Rather, the southwestward-flowing water over the Faroese slope of the Faroe–Shetland Channel is totally recirculated within the combined area of the Faroe–Shetland Channel and Wyville Thomson Basin, except possibly for a small release in the form of eddies. This does not exclude a possible westward flow over the southern tip of the Faroe Shelf, but even including that, we estimate that the average volume transport of a Circum-Faroe Current does not exceed 0.5 Sv (1 Sv = 106 m3 s−1). Also, there seems to be a persistent flow of Atlantic water from the western part of the Faroe Bank Channel into the Faroe–Shetland Channel that joins the Slope Current over the Scottish slope. These conclusions will affect potential impacts from offshore activities in the region and they imply that recently published observational estimates of the transport of warm water towards the Arctic obtained by different methods are incompatible
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Increasing transports of volume, heat, and salt towards the Arctic in the Faroe Current 1993-2013
Ocean Science Discussions, 2015Co-Authors: B. Hansen, H. Hátún, Karin Margretha H. Larsen, Regin Kristiansen, Ebba Mortensen, Svein ØsterhusAbstract:Abstract. The flow of warm and saline water from the Atlantic Ocean, across the Greenland–Scotland Ridge, into the Nordic Seas – the Atlantic inflow – is split into three separate branches. The most intensive of these branches is the inflow between Iceland and the Faroe Islands (Faroes), which is focused into the Faroe Current, north of the Faroes. The Atlantic inflow is an integral part of the North Atlantic thermohaline circulation (THC), which is projected to weaken during the 21 century and might conceivably reduce the oceanic heat and salt transports towards the Arctic. Since the mid-1990s, hydrographic properties and current velocities of the Faroe Current have been monitored along a section extending north from the Faroe shelf. From these in situ observations, time series of volume, heat, and salt transport have previously been reported, but the high variability of the transport series has made it difficult to identify trends. Here, we present results from a new analysis of the Faroe Current where the in situ observations have been combined with satellite altimetry. For the period 1993 to 2013, we find the average volume transport of Atlantic water in the Faroe Current to be 3.8 ± 0.5 Sv (1 Sv =106 m3 s−1) with a heat transport relative to 0 °C of 124 ± 15 TW (1 TW =1012 W). Consistent with other results for the Northeast Atlantic component of the THC, we find no indication of weakening. The transports of the Faroe Current, on the contrary, increased. The overall trend over the two decades of observation was 9 ± 8% for volume transport and 18 ± 9% for heat transport (95% confidence intervals). During the same period, the salt transport relative to the salinity of the deep Faroe Bank Channel overflow (34.93) more than doubled, potentially strengthening the feedback on thermohaline intensity. The increased heat and salt transports are partly caused by the increased volume transport and partly by increased temperatures and salinities of the Atlantic inflow, attributed mainly to the weakened subpolar gyre.
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Norwegian Sea overflow through the Faroe-Shetland gateway as documented by its bedforms
Marine Geology, 2002Co-Authors: A Kuijpers, B. Hansen, V Hühnerbach, B Larsen, T Nielsen, F WernerAbstract:We have used seabed information from three deep-tow side-scan sonar surveys in order to trace the high-energy current core of Norwegian Sea Overflow Water (NSOW) from the Faroe–Shetland Channel (FSC) through the Faroe Bank Channel (FBC) towards the southern flank of the Iceland–Faroe Ridge. A hierarchy of bedform types was used for estimating maximum mean near-bottom current speed, which has been compared with results from current meter measurements. We conclude that in the FSC maximum mean NSOW near-bottom flow speed at some sites may occasionally approach or even exceed 1.0 m/s. Both seabed data and oceanographic information indicate that the current core is concentrated along the Faroes slope at the 500–600-m depth stratum. With a change of the large-scale channel topography towards the southern extremity of the Faroe Plateau, where the FSC turns west towards the FBC, the slope current core gradually descends towards basin depth. Along the Wyville–Thomson Ridge (1100–1200 m water depth) maximum mean NSOW near-bottom current speed decreases slightly towards the west as the high-speed current core runs upslope the ridge. At the entrance to the narrow channel between Faroe Bank and the Faroe Plateau funnelling results in a renewed current acceleration at basin depth. Seabed evidence shows that further west in the FBC the NSOW high-speed current core is detached from the channel floor over larger areas. From the FBC outlet most of the overflow waters continue as a high-energy contour current concentrated along the southern flank of the Iceland–Faroe Ridge between 600 and 1000 m water depth.
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Norwegian Sea overflow through the Faroe–Shetland gateway as documented by its bedforms
Marine Geology, 2002Co-Authors: A Kuijpers, B. Hansen, V Hühnerbach, B Larsen, T Nielsen, F WernerAbstract:We have used seabed information from three deep-tow side-scan sonar surveys in order to trace the high-energy current core of Norwegian Sea Overflow Water (NSOW) from the Faroe–Shetland Channel (FSC) through the Faroe Bank Channel (FBC) towards the southern flank of the Iceland–Faroe Ridge. A hierarchy of bedform types was used for estimating maximum mean near-bottom current speed, which has been compared with results from current meter measurements. We conclude that in the FSC maximum mean NSOW near-bottom flow speed at some sites may occasionally approach or even exceed 1.0 m/s. Both seabed data and oceanographic information indicate that the current core is concentrated along the Faroes slope at the 500–600-m depth stratum. With a change of the large-scale channel topography towards the southern extremity of the Faroe Plateau, where the FSC turns west towards the FBC, the slope current core gradually descends towards basin depth. Along the Wyville–Thomson Ridge (1100–1200 m water depth) maximum mean NSOW near-bottom current speed decreases slightly towards the west as the high-speed current core runs upslope the ridge. At the entrance to the narrow channel between Faroe Bank and the Faroe Plateau funnelling results in a renewed current acceleration at basin depth. Seabed evidence shows that further west in the FBC the NSOW high-speed current core is detached from the channel floor over larger areas. From the FBC outlet most of the overflow waters continue as a high-energy contour current concentrated along the southern flank of the Iceland–Faroe Ridge between 600 and 1000 m water depth
