Physiological studies involving the use of isotopic water required chemical restraint of free-ranging walruses ( Odobenus rosmarus ) for several hours. In August 2000, six male walrus (total body mass: 1050–1550 kg) were immobilized in East Greenland by remote delivery of 8.0–9.8 mg of etorphine and subsequently restrained for up to 6.75 h by administration of medetomidine. The effects of etorphine were reversed with 10–24 mg diprenorphine. After termination of the etorphine-induced apnoea, lasting an average of 15.8 min (SD = 9.7, range = 9.5–35.2 min, n = 6), the animals were initially given 10–20 mg medetomidine intramuscularly. The initial dose was further augmented by 5 mg at intervals of 5 min. In two cases, when medetomidine was administered through a catheter inserted in the extradural vein, the animal became instantly apnoeic and regained respiratory function only after intravenous injection of the prescribed dose of the antagonist atipamezole and of the respiratory stimulant doxapram. After an average of 3.5 hours of immobilisation, rectal temperature began to increase and it is conceivable that this is the factor that will ultimately limit the duration of immobilisation. The animals became conscious and fully mobile shortly after an intravenous injection of a dose of atipamezole approximately twice the mass of the total dose of medetomidine given during the procedure followed by 400 mg of doxapram. It is concluded that medetomidine appears to be a suitable drug for chemical restraint of walruses for time-consuming procedures following initial immobilisation by etorphine. With animals of total body mass around 1,000–1,500 kg, the drug should be given intramuscularly in 10–20 mg increments (total mass 10–60 mg) until the breathing rate falls to approximately 1 min-1. At this level, breathing is maintained and animals do not respond to touch or injection.
涉及使用同位素水的生理研究需要对自由放养的海象(Odobenus rosmarus)进行几个小时的化学约束。2000年8月，在东格陵兰岛，6只雄性海象(总体重:1050-1550公斤)通过远程给药8.0-9.8毫克埃托啡固定，随后通过给予美托咪定限制长达6.75小时。乙托啡的作用被10-24毫克的二丙诺啡逆转。乙托啡诱导的呼吸暂停结束后，平均持续15.8 min (SD = 9.7，范围= 9.5 ~ 35.2 min, n = 6)，开始肌注美托咪定10 ~ 20 mg。初始剂量每隔5分钟增加5mg。在两个病例中，当通过硬膜外静脉插入导管给药时，动物在静脉注射处方剂量的拮抗剂阿替帕唑和呼吸兴奋剂多沙普兰后，立即出现呼吸暂停，并恢复呼吸功能。在平均3.5小时的固定后，直肠温度开始升高，可以想象这是最终限制固定时间的因素。在静脉注射一剂量的阿替帕唑(大约是美托咪定总剂量的两倍)和400毫克多沙普兰后，这些动物很快就变得有意识和完全活动。由此得出结论，美托咪定似乎是一种适合的药物，以化学约束海象的耗时程序后，最初由乙托啡固定。对于总体重在1,000-1,500 kg左右的动物，应以10-20 mg的增量(总质量10-60 mg)肌肉给药，直到呼吸速率降至约1分钟-1。在这个水平，动物保持呼吸，对触摸或注射没有反应。
{"title":"Prolonged chemical restraint of walrus ( Odobenus rosmarus ) with etorphine supplemented with medetomidine","authors":"David Griffiths, E. Born, M. Acquarone","doi":"10.7557/3.3015","DOIUrl":"https://doi.org/10.7557/3.3015","url":null,"abstract":"Physiological studies involving the use of isotopic water required chemical restraint of free-ranging walruses ( Odobenus rosmarus ) for several hours. In August 2000, six male walrus (total body mass: 1050–1550 kg) were immobilized in East Greenland by remote delivery of 8.0–9.8 mg of etorphine and subsequently restrained for up to 6.75 h by administration of medetomidine. The effects of etorphine were reversed with 10–24 mg diprenorphine. After termination of the etorphine-induced apnoea, lasting an average of 15.8 min (SD = 9.7, range = 9.5–35.2 min, n = 6), the animals were initially given 10–20 mg medetomidine intramuscularly. The initial dose was further augmented by 5 mg at intervals of 5 min. In two cases, when medetomidine was administered through a catheter inserted in the extradural vein, the animal became instantly apnoeic and regained respiratory function only after intravenous injection of the prescribed dose of the antagonist atipamezole and of the respiratory stimulant doxapram. After an average of 3.5 hours of immobilisation, rectal temperature began to increase and it is conceivable that this is the factor that will ultimately limit the duration of immobilisation. The animals became conscious and fully mobile shortly after an intravenous injection of a dose of atipamezole approximately twice the mass of the total dose of medetomidine given during the procedure followed by 400 mg of doxapram. It is concluded that medetomidine appears to be a suitable drug for chemical restraint of walruses for time-consuming procedures following initial immobilisation by etorphine. With animals of total body mass around 1,000–1,500 kg, the drug should be given intramuscularly in 10–20 mg increments (total mass 10–60 mg) until the breathing rate falls to approximately 1 min-1. At this level, breathing is maintained and animals do not respond to touch or injection.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"9 1","pages":"361-369"},"PeriodicalIF":0.0,"publicationDate":"2014-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. T. Olsen, J. Robbins, M. Bérubé, Mary Beth Rew, P. Palsbøll
This study examines the applicability of telomere length measurements by quantitative PCR as a tool for minimally invasive age determination of free-ranging cetaceans. We analysed telomere length in skin samples from 28 North Atlantic humpback whales ( Megaptera novaeangliae ), ranging from 0 to 26 years of age. The results suggested a significant correlation between telomere length and age in humpback whales. However, telomere length was highly variable among individuals of similar age, suggesting that telomere length measured by quantitative PCR is an imprecise determinant of age in humpback whales. The observed variation in individual telomere length was found to be a function of both experimental and biological variability, with the latter perhaps reflecting patterns of inheritance, resource allocation trade-offs, and stochasticity of the marine environment.
{"title":"Utility of telomere length measurements for age determination of humpback whales","authors":"M. T. Olsen, J. Robbins, M. Bérubé, Mary Beth Rew, P. Palsbøll","doi":"10.7557/3.3194","DOIUrl":"https://doi.org/10.7557/3.3194","url":null,"abstract":"This study examines the applicability of telomere length measurements by quantitative PCR as a tool for minimally invasive age determination of free-ranging cetaceans. We analysed telomere length in skin samples from 28 North Atlantic humpback whales ( Megaptera novaeangliae ), ranging from 0 to 26 years of age. The results suggested a significant correlation between telomere length and age in humpback whales. However, telomere length was highly variable among individuals of similar age, suggesting that telomere length measured by quantitative PCR is an imprecise determinant of age in humpback whales. The observed variation in individual telomere length was found to be a function of both experimental and biological variability, with the latter perhaps reflecting patterns of inheritance, resource allocation trade-offs, and stochasticity of the marine environment.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The widely accepted method of determining ages of beluga is to count dentine growth layer groups (GLGs) in median, longitudinal sections of a tooth. It is essential to understand how these growth layers form and to consider developmental factors that can confound their enumeration to be able to provide meaningful age estimates. Here we provide information on, and illustrate, the developmental biology of beluga teeth as it relates to interpreting GLGs. Key factors are: evaluating the presence and occlusal wear of fetal dentine; interpreting early-formed diagnostic features such as the neonatal line; assessing the last-formed growth layer adjacent to the pulp cavity; identifying the presence of nodes at the dentine-cementum interface to assist in counting GLGs; and recognizing pulp stones and accessory lines in the dentine which may hinder the age estimate process.
{"title":"The biology behind the counts: tooth development related to age estimation in beluga ( Delphinapterus leucas )","authors":"B. Stewart, R. Stewart","doi":"10.7557/3.3195","DOIUrl":"https://doi.org/10.7557/3.3195","url":null,"abstract":"The widely accepted method of determining ages of beluga is to count dentine growth layer groups (GLGs) in median, longitudinal sections of a tooth. It is essential to understand how these growth layers form and to consider developmental factors that can confound their enumeration to be able to provide meaningful age estimates. Here we provide information on, and illustrate, the developmental biology of beluga teeth as it relates to interpreting GLGs. Key factors are: evaluating the presence and occlusal wear of fetal dentine; interpreting early-formed diagnostic features such as the neonatal line; assessing the last-formed growth layer adjacent to the pulp cavity; identifying the presence of nodes at the dentine-cementum interface to assist in counting GLGs; and recognizing pulp stones and accessory lines in the dentine which may hinder the age estimate process.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71336180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isotopic time series from sequentially sampled growth layer groups (GLGs) in marine mammal teeth can be combined to build chronologies allowing assessment of isotopic variation in marine ecosystems. Synchronous recording of baseline isotopic variation across dentinal GLGs of species with temporal and spatial overlap in foraging offers a unique opportunity for validation of marine mammal age estimation procedures through calibration of GLG deposition rates in one species against another whose GLG deposition has been independently determined. In this study, we compare trends in stable carbon isotope ratios (d 13 C) across dentinal GLGs of three eastern Canadian Arctic (ECA) beluga ( Delphinapterus leucas ) populations through the 1960s-2000s with a d 13 C time series measured across dentinal GLGs of ECA/Northwest Atlantic killer whales ( Orcinus orca ) from 1944-1999. We use confirmed annual GLG deposition in killer whales as a means to assess beluga GLG deposition, and show linear d 13 C declines across chronologies of both species were statistically indistinguishable when based on annual GLG deposition in beluga whales, but differed when based on biannual deposition. We suggest d 13 C declines reflect the oceanic 13 C Suess effect, and provide additional support for annual GLG deposition in beluga whales by comparing rates of d 13 C declines across beluga GLGs with published annual d 13 C declines attributed to the oceanic 13 C Suess effect in the North Atlantic.
{"title":"Validation of dentine deposition rates in beluga whales by interspecies cross dating of temporal δ13C trends in teeth","authors":"C. Matthews, S. Ferguson","doi":"10.7557/3.3196","DOIUrl":"https://doi.org/10.7557/3.3196","url":null,"abstract":"Isotopic time series from sequentially sampled growth layer groups (GLGs) in marine mammal teeth can be combined to build chronologies allowing assessment of isotopic variation in marine ecosystems. Synchronous recording of baseline isotopic variation across dentinal GLGs of species with temporal and spatial overlap in foraging offers a unique opportunity for validation of marine mammal age estimation procedures through calibration of GLG deposition rates in one species against another whose GLG deposition has been independently determined. In this study, we compare trends in stable carbon isotope ratios (d 13 C) across dentinal GLGs of three eastern Canadian Arctic (ECA) beluga ( Delphinapterus leucas ) populations through the 1960s-2000s with a d 13 C time series measured across dentinal GLGs of ECA/Northwest Atlantic killer whales ( Orcinus orca ) from 1944-1999. We use confirmed annual GLG deposition in killer whales as a means to assess beluga GLG deposition, and show linear d 13 C declines across chronologies of both species were statistically indistinguishable when based on annual GLG deposition in beluga whales, but differed when based on biannual deposition. We suggest d 13 C declines reflect the oceanic 13 C Suess effect, and provide additional support for annual GLG deposition in beluga whales by comparing rates of d 13 C declines across beluga GLGs with published annual d 13 C declines attributed to the oceanic 13 C Suess effect in the North Atlantic.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71336191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Murphy, M. Perrott, Jill McVee, F. L. Read, K. A. Stockin
Knowledge of age structure and longevity (maximum age) are essential for modelling marine mammal population dynamics. Estimation of age in common dolphins ( Delphinus spp.) is primarily based on counting Growth Layer Groups (GLGs) in the dentine of thin, decalcified and stained sections of teeth. An annual incremental deposition rate was validated for Delphinus spp. 30-years ago through the use of tetracycline. However, it is not known if the pulp cavity becomes occluded in older individuals or GLGs continue to be deposited in dentine tissue. To investigate the deposition of GLGs in dentine tissue, teeth samples were obtained during the necropsies of two short-beaked common dolphins ( Delphinus delphis ) that were held in captivity for 31 and 33 years in New Zealand. Individuals were captured together in Hawkes Bay, North Island, New Zealand and classified as juveniles based on physical appearance. Teeth were processed in two ageing laboratories, using four different bone decalcifiers, two sectioning techniques incorporating the use of both a freezing microtome (-20 ° C) and paraffin microtome, and two different stains. An age was estimated for one of the dolphins, in line with that proposed based on estimated age at capture and period in captivity. However, a hypomineralised area was observed in the dentine tissue close to the pulp cavity of the second individual, preventing estimation of maximum age. The presence and structure of this anomaly is explored further within the study.
{"title":"Deposition of growth layer groups in dentine tissue of captive common dolphins Delphinus delphis","authors":"S. Murphy, M. Perrott, Jill McVee, F. L. Read, K. A. Stockin","doi":"10.7557/3.3017","DOIUrl":"https://doi.org/10.7557/3.3017","url":null,"abstract":"Knowledge of age structure and longevity (maximum age) are essential for modelling marine mammal population dynamics. Estimation of age in common dolphins ( Delphinus spp.) is primarily based on counting Growth Layer Groups (GLGs) in the dentine of thin, decalcified and stained sections of teeth. An annual incremental deposition rate was validated for Delphinus spp. 30-years ago through the use of tetracycline. However, it is not known if the pulp cavity becomes occluded in older individuals or GLGs continue to be deposited in dentine tissue. To investigate the deposition of GLGs in dentine tissue, teeth samples were obtained during the necropsies of two short-beaked common dolphins ( Delphinus delphis ) that were held in captivity for 31 and 33 years in New Zealand. Individuals were captured together in Hawkes Bay, North Island, New Zealand and classified as juveniles based on physical appearance. Teeth were processed in two ageing laboratories, using four different bone decalcifiers, two sectioning techniques incorporating the use of both a freezing microtome (-20 ° C) and paraffin microtome, and two different stains. An age was estimated for one of the dolphins, in line with that proposed based on estimated age at capture and period in captivity. However, a hypomineralised area was observed in the dentine tissue close to the pulp cavity of the second individual, preventing estimation of maximum age. The presence and structure of this anomaly is explored further within the study.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Dietz, Paul Paludan-Müller, C. Agger, C. O. Nielsen
Muscle, liver, and kidney tissue from 456 ringed seals ( Phoca hispida ) from eight areas in Greenland were analysed for cadmium, mercury, zinc and selenium. In general, cadmium concentrations were high in liver and kidney tissue, with geometric means of 7.79 and 33.5 μg/g (all data on wet weight basis), respectively. Muscle levels were considerably lower, at 0.067 μg/g. The concentration of mercury was relatively high in liver tissue with a geometric mean of 2.59 μg/g. Muscle and kidney mercury levels were somewhat lower, with geometric means of 0.210 and 0.956 μg/g, respectively. Cadmium and mercury levels were strongly dependent upon age and sampling area, as well as the interaction combinations, indicating that the accumulation of cadmium and mercury varies with age and area. Mercury accumulated in all three tissues throughout life, whereas cadmium in liver and kidneys peaked in the age group 5-10 years old where after it dropped significantly. Cadmium levels showed a tendency towards higher concentrations in the northern municipalities, which may be due to the higher cadmium levels in certain prey items in the northern areas. Mercury levels were higher in seals from East Greenland compared to West Greenland. Variations in feeding habits probably explain some of the differences in levels of cadmium and mercury in ringed seals from different geographical areas. Cadmium concentrations were correlated (both pairwise and partial) in the three organs. This was true for mercury as well, whereas only half of the combinations were significant for zinc and selenium. Cadmium was strongly correlated to mercury in all three tissues and zinc only in liver and kidneys. Mercury was only correlated to selenium in liver and not to zinc. High concentrations of cadmium were found in the bile from 58 ringed seals, and were about 10-fold higher than in muscle. The concentration of mercury in bile was relatively low, being only one third of the muscle level. The bile levels reflect that substantial amounts of especially cadmium are circulated through the bile. However, it is uncertain whether these amounts are actually excreted or reabsorbed in the intestine (enterohepatic circulation).
{"title":"Cadmium, mercury, zinc and selenium in ringed seals ( Phoca hispida ) from Greenland and Svalbard","authors":"R. Dietz, Paul Paludan-Müller, C. Agger, C. O. Nielsen","doi":"10.7557/3.2992","DOIUrl":"https://doi.org/10.7557/3.2992","url":null,"abstract":"Muscle, liver, and kidney tissue from 456 ringed seals ( Phoca hispida ) from eight areas in Greenland were analysed for cadmium, mercury, zinc and selenium. In general, cadmium concentrations were high in liver and kidney tissue, with geometric means of 7.79 and 33.5 μg/g (all data on wet weight basis), respectively. Muscle levels were considerably lower, at 0.067 μg/g. The concentration of mercury was relatively high in liver tissue with a geometric mean of 2.59 μg/g. Muscle and kidney mercury levels were somewhat lower, with geometric means of 0.210 and 0.956 μg/g, respectively. Cadmium and mercury levels were strongly dependent upon age and sampling area, as well as the interaction combinations, indicating that the accumulation of cadmium and mercury varies with age and area. Mercury accumulated in all three tissues throughout life, whereas cadmium in liver and kidneys peaked in the age group 5-10 years old where after it dropped significantly. Cadmium levels showed a tendency towards higher concentrations in the northern municipalities, which may be due to the higher cadmium levels in certain prey items in the northern areas. Mercury levels were higher in seals from East Greenland compared to West Greenland. Variations in feeding habits probably explain some of the differences in levels of cadmium and mercury in ringed seals from different geographical areas. Cadmium concentrations were correlated (both pairwise and partial) in the three organs. This was true for mercury as well, whereas only half of the combinations were significant for zinc and selenium. Cadmium was strongly correlated to mercury in all three tissues and zinc only in liver and kidneys. Mercury was only correlated to selenium in liver and not to zinc. High concentrations of cadmium were found in the bile from 58 ringed seals, and were about 10-fold higher than in muscle. The concentration of mercury in bile was relatively low, being only one third of the muscle level. The bile levels reflect that substantial amounts of especially cadmium are circulated through the bile. However, it is uncertain whether these amounts are actually excreted or reabsorbed in the intestine (enterohepatic circulation).","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"1 1","pages":"242-272"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Siegstad, P. Neve, M. Heide‐Jørgensen, T. Härkönen
Analysis of 454 stomachs of ringed seals ( Phoca hispida ) collected from the Inuit hunt in six municipalities in West Greenland and 30 alimentary tracts collected by scientists in East Greenland, showed seasonal and regional differences in the diet. In Northwest and East Greenland polar cod ( Boreogadus saida ) and Arctic cod ( Arctogadus glacialis ) were the most dominant prey items. In contrast, seals in central West Greenland mainly preyed upon amphipods ( Parathemisto spp.), capelin ( Mallotus villosus ), redfish ( Sebastes sp.) and squid ( Gonatus sp.), while capelin was the most important prey item in Southwest Greenland. The material from Uummannaq demonstrates seasonal variations, as euphausiids were common in spring, and snailfish ( Liparis spp.) dominated from October through January, where after snailfish disappeared with the formation of fast ice. No age related differences in the diet were found in stomach samples from Avanersuaq, but in Upemavik crustaceans were more abundant in stomach samples from younger immature seals. Greenland halibut ( Reinhardtius hippoglossoides ) was only present in samples from seals older than 4 years. In Upemavik Arctic cod was the dominant prey item for seals caught in May at the ice edge, whereas polar cod dominated the samples from seals caught in open water.
{"title":"Diet of the ringed seal ( Phoca hispida ) in Greenland","authors":"H. Siegstad, P. Neve, M. Heide‐Jørgensen, T. Härkönen","doi":"10.7557/3.2991","DOIUrl":"https://doi.org/10.7557/3.2991","url":null,"abstract":"Analysis of 454 stomachs of ringed seals ( Phoca hispida ) collected from the Inuit hunt in six municipalities in West Greenland and 30 alimentary tracts collected by scientists in East Greenland, showed seasonal and regional differences in the diet. In Northwest and East Greenland polar cod ( Boreogadus saida ) and Arctic cod ( Arctogadus glacialis ) were the most dominant prey items. In contrast, seals in central West Greenland mainly preyed upon amphipods ( Parathemisto spp.), capelin ( Mallotus villosus ), redfish ( Sebastes sp.) and squid ( Gonatus sp.), while capelin was the most important prey item in Southwest Greenland. The material from Uummannaq demonstrates seasonal variations, as euphausiids were common in spring, and snailfish ( Liparis spp.) dominated from October through January, where after snailfish disappeared with the formation of fast ice. No age related differences in the diet were found in stomach samples from Avanersuaq, but in Upemavik crustaceans were more abundant in stomach samples from younger immature seals. Greenland halibut ( Reinhardtius hippoglossoides ) was only present in samples from seals older than 4 years. In Upemavik Arctic cod was the dominant prey item for seals caught in May at the ice edge, whereas polar cod dominated the samples from seals caught in open water.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"1 1","pages":"229-241"},"PeriodicalIF":0.0,"publicationDate":"2014-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The size of the population of ringed seals ( Phoca hispida ) inhabiting Baffin Bay and associated waters was estimated by two methods. An approximate model of the energetics of the polar bear ( Ursus maritimus ) estimated an energetic need of about 16,000 MJ/bear per year. Modelled estimates of the energetic yield of a ringed seal population showed that a stable standing population of 140-170 ringed seals per bear would be needed to provide that much energy, assuming that all mortalities were due to polar bear predation. This result was sensitive to assumptions about the Field Metabolic Rate (FMR) of the bears and the energetic yield of individual ringed seals, but less sensitive to assumptions about relative incidence of predation on different age classes of seal or the age structure of the polar bear population. Estimated sizes of polar bear populations in Baffin Bay and associated waters (total about 4,025), and of the standing population needed to support an estimated hunter kill of 100,000 yielded a population estimate of, very roughly, 1.2 million ringed seals. Estimates of ice areas and of the density of hauled out seals from aerial surveys were used to generate another approximate figure for the ringed seal population, which was about the same. The density of seals in the pack-ice area of Baffin Bay, which is imperfectly known, has a large influence on the latter estimate.
{"title":"The numbers of ringed seals ( Phoca hispida ) in Baffin Bay and associated waters","authors":"M. Kingsley","doi":"10.7557/3.2988","DOIUrl":"https://doi.org/10.7557/3.2988","url":null,"abstract":"The size of the population of ringed seals ( Phoca hispida ) inhabiting Baffin Bay and associated waters was estimated by two methods. An approximate model of the energetics of the polar bear ( Ursus maritimus ) estimated an energetic need of about 16,000 MJ/bear per year. Modelled estimates of the energetic yield of a ringed seal population showed that a stable standing population of 140-170 ringed seals per bear would be needed to provide that much energy, assuming that all mortalities were due to polar bear predation. This result was sensitive to assumptions about the Field Metabolic Rate (FMR) of the bears and the energetic yield of individual ringed seals, but less sensitive to assumptions about relative incidence of predation on different age classes of seal or the age structure of the polar bear population. Estimated sizes of polar bear populations in Baffin Bay and associated waters (total about 4,025), and of the standing population needed to support an estimated hunter kill of 100,000 yielded a population estimate of, very roughly, 1.2 million ringed seals. Estimates of ice areas and of the density of hauled out seals from aerial surveys were used to generate another approximate figure for the ringed seal population, which was about the same. The density of seals in the pack-ice area of Baffin Bay, which is imperfectly known, has a large influence on the latter estimate.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"1 1","pages":"181-196"},"PeriodicalIF":0.0,"publicationDate":"2014-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ringed seals ( Phoca hispida ) in Thesiger Bay (about 71 °45'N, 125°00'W), in northwestern Amundsen Gulf in the western Canadian Arctic, suffered a failure of pup production in the years before 1987, starting probably in 1984. Pups taken in the summer hunt in the years before 1987 were reported scarce, and in 1987 were only 2.8% of the total 4+ and older. This low reproduction was associated with poor body condition in females and with an age distribution of adults that was weighted toward older animals (the modal year class was the 8+ class). An unusually high proportion of adult females had never reproduced; the median age of first birth was estimated at 8.6 years. By the summer of 1988 the age distribution had changed toward younger animals (modal age 5+), in better condition (by 20%), which had almost all ovulated. Pups were more numerous in the catch. In 1989 pups were very numerous in the catch (142% of the 4+ adults) and the estimated mean age of first birth had decreased to 5.3 years; almost all 5-year-olds sampled had borne pups. A similar occurrence of low pup production had been documented in the early 1970s, and resumption of reproductive activity had then also been associated with an apparent turnover of the population, the mean age of adults decreasing from 16-17 years when reproduction was low to 10.9 years in the year before reproduction resumed. Long-term data on ringed seals in the western Canadian Arctic has shown an average age at first ovulation of about 5.55 years and first birth just before age 7, about 1 year older than seen in this sample in 1989. Our 1989 sample may have been able to mature earlier because food was temporarily more abundant, or breeding densities temporarily lower, than long-term average values.
{"title":"Failure of reproduction in ringed seals ( Phoca hispida ) in Amundsen Gulf, Northwest Territories in 1984-1987","authors":"M. Kingsley, T. Byers","doi":"10.7557/3.2989","DOIUrl":"https://doi.org/10.7557/3.2989","url":null,"abstract":"Ringed seals ( Phoca hispida ) in Thesiger Bay (about 71 °45'N, 125°00'W), in northwestern Amundsen Gulf in the western Canadian Arctic, suffered a failure of pup production in the years before 1987, starting probably in 1984. Pups taken in the summer hunt in the years before 1987 were reported scarce, and in 1987 were only 2.8% of the total 4+ and older. This low reproduction was associated with poor body condition in females and with an age distribution of adults that was weighted toward older animals (the modal year class was the 8+ class). An unusually high proportion of adult females had never reproduced; the median age of first birth was estimated at 8.6 years. By the summer of 1988 the age distribution had changed toward younger animals (modal age 5+), in better condition (by 20%), which had almost all ovulated. Pups were more numerous in the catch. In 1989 pups were very numerous in the catch (142% of the 4+ adults) and the estimated mean age of first birth had decreased to 5.3 years; almost all 5-year-olds sampled had borne pups. A similar occurrence of low pup production had been documented in the early 1970s, and resumption of reproductive activity had then also been associated with an apparent turnover of the population, the mean age of adults decreasing from 16-17 years when reproduction was low to 10.9 years in the year before reproduction resumed. Long-term data on ringed seals in the western Canadian Arctic has shown an average age at first ovulation of about 5.55 years and first birth just before age 7, about 1 year older than seen in this sample in 1989. Our 1989 sample may have been able to mature earlier because food was temporarily more abundant, or breeding densities temporarily lower, than long-term average values.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"1 1","pages":"197-210"},"PeriodicalIF":0.0,"publicationDate":"2014-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. O. Kapel, J. Christiansen, M. Heide‐Jørgensen, T. Härkönen, E. Born, L. O. Knutsen, F. Rigét, J. Teilmann
Seven studies of netting and tagging of ringed seals ( Phoca hispida ) in Greenland 1976-1997 are described. The areas of operation were: northern part of the Upernavik area (Northwest Greenland), Kong Oscars Fjord (Northeast Greenland), and Avanersuaq (Thule, North Greenland). Altogether, 135 seals were caught, of which 99 were tagged and released with Dalton Jumbo rototags. Recapture of 38 tagged seals has been reported to date. The recaptures demonstrate movements of ringed seals in Greenland of more than 100km within districts, as well as long-distance movements of more than 1000km from the site of release.
{"title":"Netting and conventional tagging used to study movements of ringed seals ( Phoca hispida ) in Greenland","authors":"F. O. Kapel, J. Christiansen, M. Heide‐Jørgensen, T. Härkönen, E. Born, L. O. Knutsen, F. Rigét, J. Teilmann","doi":"10.7557/3.2990","DOIUrl":"https://doi.org/10.7557/3.2990","url":null,"abstract":"Seven studies of netting and tagging of ringed seals ( Phoca hispida ) in Greenland 1976-1997 are described. The areas of operation were: northern part of the Upernavik area (Northwest Greenland), Kong Oscars Fjord (Northeast Greenland), and Avanersuaq (Thule, North Greenland). Altogether, 135 seals were caught, of which 99 were tagged and released with Dalton Jumbo rototags. Recapture of 38 tagged seals has been reported to date. The recaptures demonstrate movements of ringed seals in Greenland of more than 100km within districts, as well as long-distance movements of more than 1000km from the site of release.","PeriodicalId":30560,"journal":{"name":"NAMMCO Scientific Publications","volume":"36 1","pages":"211-228"},"PeriodicalIF":0.0,"publicationDate":"2014-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71335816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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