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Clark CT, Yang P, Halden N, Ferguson SH, Matthews CJD. Patterns of trace element deposition in beluga whale teeth reflect early life history. CHEMOSPHERE 2023; 340:139938. [PMID: 37634591 DOI: 10.1016/j.chemosphere.2023.139938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
Determination of trace element concentrations in continuously growing biological structures such as otoliths, whiskers, and teeth can provide important insight into physiological and ontogenetic processes. We examined concentrations of 11 trace elements (Li, Mg, Mn, Cu, Zn, Se, Rb, Sr, Cs, Ba, Pb) in the annual dentine growth layer groups (GLGs) of teeth of 66 Eastern Canadian Arctic belugas (Delphinapterus leucas). Several of these trace elements displayed clear and consistent patterns in early life, though few longer term trends or signals were present in trace element data for either females or males. Large changes in Sr and Ba concentrations in fetal dentine reflected in utero shifts in element deposition in the teeth of developing belugas. Marked changes in these elements during the first years after birth were likely associated with the onset of nursing and subsequent weaning. Mg, Mn, and Zn also displayed clear and consistent patterns in early life that correlated strongly with dentine stable nitrogen isotope (δ15N) data, suggesting these elements merit further study as potential tools for studying nursing and weaning. Depositional patterns of Zn and Pb, which have been linked to sexual maturation in female Pacific walruses (Odobenus rosmarus divergens), were inconsistent in beluga teeth. Some individuals (including males) displayed patterns strongly resembling those observed in female walruses, whereas many animals did not, perhaps because they had not yet reached sexual maturity. The lack of clear patterns in trace element deposition after the first few years of life may have resulted from pooling samples from multiple populations/regions collected across more than two decades, but may also indicate that elemental concentrations are primarily driven by other, extrinsic processes later in life, and might be useful as biomonitors of environmental element concentrations or tools for delineating population structure.
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Affiliation(s)
- Casey T Clark
- Washington Department of Fish & Wildlife, Olympia, WA, USA.
| | - Panseok Yang
- Department of Geological Sciences, University of Manitoba, Winnipeg MB, R3T 2N6, Canada
| | - Norm Halden
- Department of Geological Sciences, University of Manitoba, Winnipeg MB, R3T 2N6, Canada
| | - Steven H Ferguson
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Cory J D Matthews
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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Martin JE, Tacail T, Simon L, Hassler A, Télouk P, Balter V. Inferring odontocete life history traits in dentine using a multiproxy approach (δ 15 N, δ 44/42 Ca and trace elements). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9612. [PMID: 37698152 DOI: 10.1002/rcm.9612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 09/13/2023]
Abstract
RATIONALE Understanding the interactions between marine mammals and their environment is critical for ecological and conservation purposes. Odontocetes offer a continuous record of their life history from birth as recorded in annual increments of their tooth dentine. Because dentine is not remodeled and contains collagen, nitrogen stable isotope compositions (δ15 N) reflect nursing and weaning events, life history traits that would otherwise be impossible to retrieve in such elusive marine animals. Yet, capturing the magnitude and temporal changes in these events is constrained by tooth size and sampling resolution. Moreover, historical and fossil specimens undergo collagen decay, hence the need to develop the measurements of other proxies. METHODS Here, we present a multiproxy approach to investigate the use of Ca isotope compositions (δ44/42 Ca) in relation to δ15 N and laser ablation profiles for different trace metal (Ba, Mg, Sr, Zn) concentrations across the dentine of a single individual of the common bottlenose dolphin Tursiops truncatus. RESULTS To help interpret the dentine data, we provide milk elemental compositions and δ44/42 Ca values for two odontocete individuals. We discuss the observed changes in δ44/42 Ca across the dentine as potential markers of birth, weaning interval, incidental ingestion of seawater, trophic level and physiology. Incidental ingestion of seawater during nursing induces a positive offset in δ44/42 Ca values recorded in the early formed dentine. CONCLUSIONS Life history parameters of individual marine mammals are extremely difficult to retrieve due to limitations in observing specimens in the wild and the methodology presented here offers new ecological and paleoecological perspectives.
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Affiliation(s)
- Jeremy E Martin
- Laboratoire de Géologie de Lyon: Terre, Planètes, Environnements, UMR 5276, CNRS, Ecole Normale supérieure de Lyon, Lyon, France
| | - Théo Tacail
- Institute of Geosciences, Johannes Gutenberg University, Mainz, Germany
| | - Laurent Simon
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, Villeurbanne, France
| | - Auguste Hassler
- Department of Archaeology, University of Aberdeen, Aberdeen, UK
- Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Philippe Télouk
- Laboratoire de Géologie de Lyon: Terre, Planètes, Environnements, UMR 5276, CNRS, Ecole Normale supérieure de Lyon, Lyon, France
| | - Vincent Balter
- Laboratoire de Géologie de Lyon: Terre, Planètes, Environnements, UMR 5276, CNRS, Ecole Normale supérieure de Lyon, Lyon, France
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Renaud LA, Bordeleau X, Kellar NM, Pigeon G, Michaud R, Morin Y, Lair S, Therien A, Lesage V. Estimating pregnancy rate from blubber progesterone levels of a blindly biopsied beluga population poses methodological, analytical and statistical challenges. CONSERVATION PHYSIOLOGY 2023; 11:coad075. [PMID: 37771677 PMCID: PMC10533324 DOI: 10.1093/conphys/coad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 07/13/2023] [Accepted: 09/06/2023] [Indexed: 09/30/2023]
Abstract
Beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada, have been declining since the early 2000s, suggesting recruitment issues as a result of low fecundity, abnormal abortion rates or poor calf or juvenile survival. Pregnancy is difficult to observe in cetaceans, making the ground truthing of pregnancy estimates in wild individuals challenging. Blubber progesterone concentrations were contrasted among 62 SLE beluga with a known reproductive state (i.e. pregnant, resting, parturient and lactating females), that were found dead in 1997 to 2019. The suitability of a threshold obtained from decaying carcasses to assess reproductive state and pregnancy rate of freshly-dead or free-ranging and blindly-sampled beluga was examined using three statistical approaches and two data sets (135 freshly harvested carcasses in Nunavik, and 65 biopsy-sampled SLE beluga). Progesterone concentrations in decaying carcasses were considerably higher in known-pregnant (mean ± sd: 365 ± 244 ng g-1 of tissue) than resting (3.1 ± 4.5 ng g-1 of tissue) or lactating (38.4 ± 100 ng g-1 of tissue) females. An approach based on statistical mixtures of distributions and a logistic regression were compared to the commonly-used, fixed threshold approach (here, 100 ng g-1) for discriminating pregnant from non-pregnant females. The error rate for classifying individuals of known reproductive status was the lowest for the fixed threshold and logistic regression approaches, but the mixture approach required limited a priori knowledge for clustering individuals of unknown pregnancy status. Mismatches in assignations occurred at lipid content < 10% of sample weight. Our results emphasize the importance of reporting lipid contents and progesterone concentrations in both units (ng g-1 of tissue and ng g-1 of lipid) when sample mass is low. By highlighting ways to circumvent potential biases in field sampling associated with capturability of different segments of a population, this study also enhances the usefulness of the technique for estimating pregnancy rate of free-ranging population.
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Affiliation(s)
- L -A Renaud
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, P.O. Box 1000, 850 Route de la Mer, Mont-Joli, Québec, G5H 3Z4, Canada
| | - X Bordeleau
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, P.O. Box 1000, 850 Route de la Mer, Mont-Joli, Québec, G5H 3Z4, Canada
| | - N M Kellar
- Southwest Fisheries Science Center, National Marine Fisheries Service, P.O. Box 271, La Jolla, California 92038, USA
| | - G Pigeon
- Institut de recherche sur les forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec, J9X 5E4, Canada
| | - R Michaud
- Groupe de recherche et d’éducation sur les mammifères marins (GREMM), 108 de la Cale-Sèche, Tadoussac, Québec, G0T 2A0, Canada
| | - Y Morin
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, P.O. Box 1000, 850 Route de la Mer, Mont-Joli, Québec, G5H 3Z4, Canada
| | - S Lair
- Faculté de médecine vétérinaire, Université de Montréal, P.O. Box 5000, 3200 Rue Sicotte, St-Hyacinthe, Québec, J2S 7C6, Canada
| | - A Therien
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, P.O. Box 1000, 850 Route de la Mer, Mont-Joli, Québec, G5H 3Z4, Canada
| | - V Lesage
- Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, P.O. Box 1000, 850 Route de la Mer, Mont-Joli, Québec, G5H 3Z4, Canada
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Rey-Iglesia A, Wilson T, Routledge J, Skovrind M, Garde E, Heide-Jørgensen MP, Szpak P, Lorenzen ED. Combining δ13C and δ15N from bone and dentine in marine mammal palaeoecological research: insights from toothed whales. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2023; 59:66-77. [PMID: 36445837 DOI: 10.1080/10256016.2022.2145285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions of bone and dentine collagen extracted from museum specimens have been widely used to study the paleoecology of past populations. Due to possible systematic differences in stable isotope values between bone and dentine, dentine values need to be transformed into bone-collagen equivalent using a correction factor to allow comparisons between the two collagen sources. Here, we provide correction factors to transform dentine δ13C and δ15N values into bone-collagen equivalent for two toothed whales: narwhal and beluga. We sampled bone and dentine from the skulls of 11 narwhals and 26 belugas. In narwhals, dentine was sampled from tusk and embedded tooth; in belugas, dentine was sampled from tooth. δ13C and δ15N were measured, and intra-individual bone and dentine isotopic compositions were used to calculate correction factors for each species. We detected differences in δ13C and δ15N. In both narwhals and belugas, we found lower average δ13C and δ15N in bone compared with dentine. The correction factors provided by the study enable the combined analysis of stable isotope data from bone and dentine in these species.
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Affiliation(s)
| | | | | | - Mikkel Skovrind
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Eva Garde
- Greenland Institute of Natural Resources, Copenhagen, Denmark
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Troina GC, Teixeira CR, Dehairs F, Secchi ER, Botta S. Potential biases in dietary interpretation derived from stable isotope analysis of small dolphin teeth. MARINE ENVIRONMENTAL RESEARCH 2023; 184:105857. [PMID: 36577309 DOI: 10.1016/j.marenvres.2022.105857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/23/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
We analyzed δ13C and δ15N values in different tooth portions (Growth Layer Groups, GLGs) of franciscanas, Pontoporia blainvillei, to investigate their effect on whole tooth (WT) isotopic values and the implications for dietary estimates. Tooth portions included the dentin deposited during the prenatal development (PND), the first year of life (GLG1) deposited during the nursing period and the central part of the tooth with no distinction amongst subsequent GLGs (Center). Isotopic mixing models estimating the contribution of PND, GLG1 and Center to WT showed that GLG1 has a strong effect on WT isotope values in juveniles, while Center only starts to affect WT isotopic values from age four. Isotopic mixing models estimating prey contribution to the diet of juveniles using WT vs Center tooth portions significantly differed in dietary outputs, demonstrating that GLG1 influence on WT isotope values affects dietary estimates in young franciscanas. As the small tooth size and narrowness of the last GLGs hinder the analysis of individual layers, we recommend excluding GLG1 in studies based on teeth isotope composition in franciscanas and caution when interpreting isotopic values from the WT of other small cetaceans.
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Affiliation(s)
- Genyffer C Troina
- Laboratório de Ecologia e Conservação da Megafauna Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Av. Itália, km 8, Rio Grande, RS, 96203-900, Brazil; Analytical, Environmental and Geo-Chemistry Department (AMGC), Vrije Universiteit Brussel (VUB), B-1050, Brussels, Belgium; Institute for the Oceans and Fisheries, University of British Columbia (UBC), V6T 1Z4, Vancouver, BC, Canada.
| | - Clarissa R Teixeira
- Whale Habitat, Ecology and Telemetry Laboratory, Marine Mammal Institute, Oregon State University, Newport, OR, USA
| | - Frank Dehairs
- Analytical, Environmental and Geo-Chemistry Department (AMGC), Vrije Universiteit Brussel (VUB), B-1050, Brussels, Belgium
| | - Eduardo R Secchi
- Laboratório de Ecologia e Conservação da Megafauna Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Av. Itália, km 8, Rio Grande, RS, 96203-900, Brazil
| | - Silvina Botta
- Laboratório de Ecologia e Conservação da Megafauna Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Av. Itália, km 8, Rio Grande, RS, 96203-900, Brazil
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McHuron EA, Adamczak S, Costa DP, Booth C. Estimating reproductive costs in marine mammal bioenergetic models: a review of current knowledge and data availability. CONSERVATION PHYSIOLOGY 2023; 11:coac080. [PMID: 36685328 PMCID: PMC9845964 DOI: 10.1093/conphys/coac080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 11/26/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Reproductive costs represent a significant proportion of a mammalian female's energy budget. Estimates of reproductive costs are needed for understanding how alterations to energy budgets, such as those from environmental variation or human activities, impact maternal body condition, vital rates and population dynamics. Such questions are increasingly important for marine mammals, as many populations are faced with rapidly changing and increasingly disturbed environments. Here we review the different energetic costs that marine mammals incur during gestation and lactation and how those costs are typically estimated in bioenergetic models. We compiled data availability on key model parameters for each species across all six marine mammal taxonomic groups (mysticetes, odontocetes, pinnipeds, sirenians, mustelids and ursids). Pinnipeds were the best-represented group regarding data availability, including estimates of milk intake, milk composition, lactation duration, birth mass, body composition at birth and growth. There were still considerable data gaps, particularly for polar species, and good data were only available across all parameters in 45% of pinniped species. Cetaceans and sirenians were comparatively data-poor, with some species having little or no data for any parameters, particularly beaked whales. Even for species with moderate data coverage, many parameter estimates were tentative or based on indirect approaches, necessitating reevaluation of these estimates. We discuss mechanisms and factors that affect maternal energy investment or prey requirements during reproduction, such as prey supplementation by offspring, metabolic compensation, environmental conditions and maternal characteristics. Filling the existing data gaps highlighted in this review, particularly for parameters that are influential on bioenergetic model outputs, will help refine reproductive costs estimated from bioenergetic models and better address how and when energy imbalances are likely to affect marine mammal populations.
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Affiliation(s)
- Elizabeth A McHuron
- Corresponding author: Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, WA, 98105, USA.
| | - Stephanie Adamczak
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Cormac Booth
- SMRU Consulting, Scottish Oceans Institute, St Andrews, UK
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Ferguson SH, Yurkowski DJ, Hudson JM, Edkins T, Willing C, Watt CA. Larger body size leads to greater female beluga whale ovarian reproductive activity at the southern periphery of their range. Ecol Evol 2021; 11:17314-17322. [PMID: 34938510 PMCID: PMC8668808 DOI: 10.1002/ece3.8367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 10/05/2021] [Accepted: 11/02/2021] [Indexed: 12/22/2022] Open
Abstract
Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species' geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to ovarian reproductive activity (ORA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Our study aim was to assess the relative influence of age and body size of female beluga whale on ORA in the two populations. Female beluga whale ORA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whales accounted for considerably more of the total variation (12% vs. 1%) in ORA compared to BB whales. We speculate that female HB beluga whale ORA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how ORA varies across a species' range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.
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Affiliation(s)
- Steven H. Ferguson
- Fisheries and Oceans CanadaFreshwater InstituteWinnipegManitobaCanada
- Biological SciencesUniversity of ManitobaWinnipegManitobaCanada
| | - David J. Yurkowski
- Fisheries and Oceans CanadaFreshwater InstituteWinnipegManitobaCanada
- Biological SciencesUniversity of ManitobaWinnipegManitobaCanada
| | - Justine M. Hudson
- Fisheries and Oceans CanadaFreshwater InstituteWinnipegManitobaCanada
| | - Tera Edkins
- Fisheries and Oceans CanadaFreshwater InstituteWinnipegManitobaCanada
| | | | - Cortney A. Watt
- Fisheries and Oceans CanadaFreshwater InstituteWinnipegManitobaCanada
- Biological SciencesUniversity of ManitobaWinnipegManitobaCanada
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Abstract
Abstract
Allocare, investment in offspring from non-parents, poses an evolutionary enigma. While the fitness trade-offs driving parental care are universal, alloparents may be driven by kin selection, reciprocation, the need to acquire parenting skills (‘learning-to-parent’), an indiscriminate attraction towards infants (‘natal attraction’), or a combination of multiple drivers. Among belugas (Delphinapterus leucas), allocare has been reported in wild and captive populations, but its underlying mechanisms remain untested. Using over 1800 focal observations, we quantified alloparental associations in St. Lawrence Estuary (SLE) belugas to determine whether the learning-to-parent and natal attraction hypotheses are consistent with patterns of allocare in this population. We found that subadults showed little interest in providing allocare and that alloparental investment remained constant across offspring age classes. As the observed patterns of allocare are inconsistent with both the learning-to-parent and natal attraction hypotheses, allocare in SLE belugas is likely driven by kin selection, reciprocation, or a combination thereof.
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Affiliation(s)
- Jaclyn A. Aubin
- Cognitive and Behavioural Ecology, Dean of Science Office, Memorial University of Newfoundland, St. John’s, NL, Canada A1B 3X7
| | - Robert Michaud
- Groupe de Recherche et d’Éducation sur les Mammifères Marins, Québec, 870 Salaberry Avenue, Bureau R24, Québec, QC, Canada G1R 2T9
| | - Eric Vander Wal
- Cognitive and Behavioural Ecology, Dean of Science Office, Memorial University of Newfoundland, St. John’s, NL, Canada A1B 3X7
- Department of Biology, 232 Elizabeth Avenue, Memorial University of Newfoundland, St. John’s, NL, Canada A1B 3X9
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Louis M, Skovrind M, Garde E, Heide-Jørgensen MP, Szpak P, Lorenzen ED. Population-specific sex and size variation in long-term foraging ecology of belugas and narwhals. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202226. [PMID: 33972883 PMCID: PMC8074634 DOI: 10.1098/rsos.202226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Intraspecific variation in resource use by individuals of different age, sex or size may reflect differing energetic requirements and physiological constraints. Males and females often show differences in diet owing to sexual size dimorphism, different life histories and/or habitat use. Here, we investigate how sex and size influence the long-term foraging ecology of belugas and narwhals in Greenland, using stable isotopes of carbon and nitrogen from bone collagen. We show that males have a higher trophic level and a larger ecological niche than females in West Greenland belugas and in East Greenland narwhals. In addition, for these two populations, we find that δ 15N increases with size, particularly in males. We hypothesize that sexual size dimorphism together with strong maternal investment drive these differences. By contrast, we find no differences in foraging ecology between sexes in West Greenland narwhals and observe no influence of size on trophic level. This may reflect the influence of interspecific competition in West Greenland, where the distributions of belugas and narwhals overlap, and/or geographical resource partitioning among different summer aggregations of narwhals. Our results suggest that sex and size variations in diet are population dependent, and probably the result of varying ecological interactions.
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Affiliation(s)
- Marie Louis
- Globe Institute, University of Copenhagen, Denmark
| | | | - Eva Garde
- Greenland Institute of Natural Resources, Copenhagen, Denmark
| | | | - Paul Szpak
- Trent University, Peterborough, Ontario, Canada
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Hudson JM, Matthews CJD, Watt CA. Detection of steroid and thyroid hormones in mammalian teeth. CONSERVATION PHYSIOLOGY 2021; 9:coab087. [PMID: 36439380 PMCID: PMC8633673 DOI: 10.1093/conphys/coab087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 08/30/2021] [Accepted: 10/27/2021] [Indexed: 05/21/2023]
Abstract
Endocrine tools can provide an avenue to better understand mammalian life histories and predict how individuals and populations may respond to environmental stressors; however, few options exist for studying long-term endocrine patterns in individual marine mammals. Here, we (i) determined whether hormones could be measured in teeth from four marine mammal species: narwhal (Monodon monoceros), beluga (Delphinapterus leucas), killer whale (Orcinus orca) and Atlantic walrus (Odobenus rosmarus rosmarus); (ii) validated commercially available enzyme immunoassay kits for use with tooth extracts; and (iii) conducted biological validations for each species to determine whether reproductive hormone concentrations in teeth correlated with age of sexual maturity. Tooth extracts from all species had measurable concentrations of progesterone, testosterone, 17β-estradiol, corticosterone, aldosterone and triiodothyronine (T3); however, cortisol was undetectable. Parallelism between the binding curves of assay kit standards and serially diluted pools of tooth extract for each species was observed for all measurable hormones. Slopes of accuracy tests ranged from 0.750 to 1.116, with r2 values ranging from 0.977 to 1.000, indicating acceptable accuracy. Biological validations were inconsistent with predictions for each species, with the exception of female killer whales (n = 2), which assumed higher progesterone and testosterone concentrations in mature individuals than immature individuals. Instead, we observed a decline in progesterone and testosterone concentrations from infancy through adulthood in narwhal (n = 1) and walruses (n = 2) and higher reproductive hormone concentrations in immature individuals than mature individuals in belugas (n = 8 and 10, respectively) and male killer whales (n = 1 and 2, respectively). While unexpected, this pattern has been observed in other taxa; however, further analytical and biological validations are necessary before this technique can be used to assess individual mammalian endocrine patterns.
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Affiliation(s)
- Justine M Hudson
- Corresponding author: Fisheries and Oceans Canada, Winnipeg, R3T 2N6, Canada. Tel: 1 (204) 984-0550.
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Hastings KK, Johnson DS, Pendleton GW, Fadely BS, Gelatt TS. Investigating life-history traits of Steller sea lions with multistate hidden Markov mark-recapture models: Age at weaning and body size effects. Ecol Evol 2021; 11:714-734. [PMID: 33520160 PMCID: PMC7820167 DOI: 10.1002/ece3.6878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 11/07/2022] Open
Abstract
The duration of offspring care is critical to female fitness and population resilience by allowing flexibility in life-history strategies in a variable environment. Yet, for many mammals capable of extended periods of maternal care, estimates of the duration of offspring dependency are not available and the relative importance of flexibility of this trait on fitness and population viability has rarely been examined. We used data from 4,447 Steller sea lions Eumetopias jubatus from the Gulf of Alaska and multistate hidden Markov mark-recapture models to estimate age-specific weaning probabilities. Maternal care beyond age 1 was common: Weaning was later for animals from Southeast Alaska (SEAK) and Prince William Sound (PWS, weaning probabilities: 0.536-0.648/0.784-0.873 by age 1/2) compared with animals born to the west (0.714-0.855/0.798-0.938). SEAK/PWS animals were also smaller than those born farther west, suggesting a possible link. Females weaned slightly earlier (+0.080 at age 1 and 2) compared with males in SEAK only. Poor survival for weaned versus unweaned yearlings occurred in southern SEAK (female survival probabilities: 0.609 vs. 0.792) and the central Gulf (0.667 vs. 0.901), suggesting poor conditions for juveniles in these areas. First-year survival increased with neonatal body mass (NBM) linearly in the Gulf and nonlinearly in SEAK. The probability of weaning at age 1 increased linearly with NBM for SEAK animals only. Rookeries where juveniles weaned at earlier ages had lower adult female survival, but age at weaning was unrelated to population trends. Our results suggest the time to weaning may be optimized for different habitats based on long-term average conditions (e.g., prey dynamics), that may also shape body size, with limited short-term plasticity. An apparent trade-off of adult survival in favor of juvenile survival and large offspring size in the endangered Gulf of Alaska population requires further study.
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Affiliation(s)
- Kelly K. Hastings
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
| | - Devin S. Johnson
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
| | - Grey W. Pendleton
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
| | - Brian S. Fadely
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
| | - Thomas S. Gelatt
- NOAA FisheriesAlaska Fisheries Science CenterSeattleWashingtonUSA
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12
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Clark CT, Horstmann L, Misarti N. Evaluating tooth strontium and barium as indicators of weaning age in Pacific walruses. Methods Ecol Evol 2020; 11:1626-1638. [PMID: 33381293 PMCID: PMC7756818 DOI: 10.1111/2041-210x.13482] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 08/20/2020] [Indexed: 11/30/2022]
Abstract
Lactation length and weaning age provide important information about maternal investment, which can reflect the health and nutritional status of the mother, as well as broader reproductive strategies in mammals. Calcium-normalized strontium (Sr) and barium (Ba) concentrations in the growth layers of mammalian teeth differ for nursing animals and those consuming non-milk foods, thus can be used to estimate age-at-weaning. To date, this approach has been used only for terrestrial animals, and almost exclusively for primates.The goal of this study was to determine whether Sr and Ba concentrations in the cementum of Pacific walrus Odobenus rosmarus divergens teeth can be used to estimate weaning age. Teeth from 107 walruses were analysed using laser ablation inductively coupled plasma mass spectrometry, and calcium-normalized 88Sr and 137Ba concentrations were quantified.For most walruses, both Sr and Ba concentrations exhibited rapid changes in early life. Ba concentrations matched closely with expected patterns in the published literature, rapidly declining from high to low concentrations (typically from ~10 ppm to ~5 ppm). In contrast, Sr exhibited a pattern opposite to that presented in studies of terrestrial mammals, appearing nearly identical to Ba (typically declining from ~400 ppm to ~200 ppm). To explain these findings, we present conceptual models of the factors generating weaning signals in Sr and Ba for terrestrial mammals, as well as a new, hypothetical model for walruses. Both a visual and mathematical approach to weaning age estimation indicated a median weaning age of walruses at the end of the second year of life (in the second dark layer of the tooth cementum), with many walruses estimated to have weaned in their third year of life, and a smaller group weaning in their fourth or fifth year. This is later than expected, given a published estimate of walrus weaning at 18-24 months.These results do not conclusively support the use of tooth Sr and Ba for estimating weaning age in walruses, and further research is warranted to better understand the drivers of the observed patterns of Ba and Sr accumulation in walrus teeth.
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Affiliation(s)
- Casey T. Clark
- Joint Institute for the Study of Atmosphere and OceanUniversity of WashingtonSeattleWAUSA
- Cooperative Institute for Climate, Ocean, and Ecosystem StudiesUniversity of WashingtonSeattleWAUSA
| | - Lara Horstmann
- College of Fisheries and Ocean SciencesUniversity of Alaska FairbanksFairbanksAKUSA
| | - Nicole Misarti
- Water and Environmental Research CenterUniversity of Alaska FairbanksFairbanksAKUSA
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McGuire TL, Stephens AD, McClung JR, Garner CD, Shelden KEW, Boor GKH, Wright B. Reproductive natural history of endangered Cook Inlet Beluga whales: insights from a long-term photo-identification study. Polar Biol 2020. [DOI: 10.1007/s00300-020-02750-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Feyrer LJ, Zhao ST, Whitehead H, Matthews CJD. Prolonged maternal investment in northern bottlenose whales alters our understanding of beaked whale reproductive life history. PLoS One 2020; 15:e0235114. [PMID: 32574188 PMCID: PMC7310684 DOI: 10.1371/journal.pone.0235114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/09/2020] [Indexed: 12/03/2022] Open
Abstract
Nursing and weaning periods are poorly understood in cetaceans due to the difficulty of assessing underwater behaviour in the wild. However, the onset and completion of weaning are critical turning points for individual development and survival, with implications for a species' life history including reproductive potential. δ15N and δ13C deposited in odontocete teeth annuli provide a lifetime record of diet, offering an opportunity to investigate variation and trends in fundamental biology. While available reproductive parameters for beaked whales have largely been inferred from single records of stranded or hunted animals and extrapolated across species, here we examine the weaning strategy and nursing duration in northern bottlenose whales (Hyperoodon ampullatus) by measuring stable isotopes deposited in dentine growth layer groups (GLGs). Using a collection of H. ampullatus teeth taken from whales killed during the whaling era (N = 48) and from two stranded specimens, we compared ontogenetic variation of δ15N and δ13C found in annual GLGs across all individuals, by sex and by region. We detected age-based trends in both δ15N and δ13C that are consistent across regions and males and females, and indicate that nursing is prolonged and weaning does not conclude until whales are 3-4 years old, substantially later than previous estimates of 1 year. Incorporating a prolonged period of maternal care into H. ampullatus life history significantly reduces their reproductive potential, with broad implications for models of beaked whale life history, energetics and the species' recovery from whaling.
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Affiliation(s)
- Laura Joan Feyrer
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Shu ting Zhao
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Canada
| | - Hal Whitehead
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Cory J. D. Matthews
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Canada
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Nelson MA, Quakenbush LT, Mahoney BA, Taras BD, Wooller MJ. Fifty years of Cook Inlet beluga whale feeding ecology from isotopes in bone and teeth. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00890] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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16
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Lemieux Lefebvre S, Lesage V, Michaud R, Humphries M. Classifying and combining herd surface activities and individual dive profiles to identify summer behaviours of beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies of the behaviour of diving animals usually focus on either individual dives or surface group activities, but these complementary observations are seldom combined in the same study. We here study the summer (June–October) behaviour of St. Lawrence Estuary belugas (Delphinapterus leucas (Pallas, 1776)) by combining fine-scale individual diving data from 27 time–depth–speed recorder deployments (conducted in 2002–2005) with surface activity data from 1413 focal herd follows (conducted in 1991–2012). We classified 6312 dives into seven dive types based on shape and swim speed. Dives were then combined into five bout types, including three pelagic, one benthic, and one near-surface. We classified surface activities of herds into six clusters, differentiated primarily by their associated movement patterns (milling or directional) and additionally by herd structure and dispersion and occurrence of acrobatic surface events. Finally, we used herd focal follows conducted while tracking an individual beluga to relate dive and bout types to surface activities. Results indicate that milling at the surface was more frequently related to benthic dives, potentially, associated with behaviours such as benthic foraging, resting, socializing, and care of young. Directional surface movements were more frequently associated with pelagic dives likely used during pelagic foraging, exploration, and travelling.
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Affiliation(s)
- S. Lemieux Lefebvre
- Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
| | - V. Lesage
- Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, QC G5H 3Z4, Canada
| | - R. Michaud
- Groupe de recherche et d’éducation sur les mammifères marins, Tadoussac, QC G0T 2A0, Canada
| | - M.M. Humphries
- Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
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O’Corry-Crowe G, Suydam R, Quakenbush L, Potgieter B, Harwood L, Litovka D, Ferrer T, Citta J, Burkanov V, Frost K, Mahoney B. Migratory culture, population structure and stock identity in North Pacific beluga whales (Delphinapterus leucas). PLoS One 2018; 13:e0194201. [PMID: 29566001 PMCID: PMC5863979 DOI: 10.1371/journal.pone.0194201] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 02/27/2018] [Indexed: 01/31/2023] Open
Abstract
The annual return of beluga whales, Delphinapterus leucas, to traditional seasonal locations across the Arctic may involve migratory culture, while the convergence of discrete summering aggregations on common wintering grounds may facilitate outbreeding. Natal philopatry and cultural inheritance, however, has been difficult to assess as earlier studies were of too short a duration, while genetic analyses of breeding patterns, especially across the beluga's Pacific range, have been hampered by inadequate sampling and sparse information on wintering areas. Using a much expanded sample and genetic marker set comprising 1,647 whales, spanning more than two decades and encompassing all major coastal summering aggregations in the Pacific Ocean, we found evolutionary-level divergence among three geographic regions: the Gulf of Alaska, the Bering-Chukchi-Beaufort Seas, and the Sea of Okhotsk (Φst = 0.11-0.32, Rst = 0.09-0.13), and likely demographic independence of (Fst-mtDNA = 0.02-0.66), and in many cases limited gene flow (Fst-nDNA = 0.0-0.02; K = 5-6) among, summering groups within regions. Assignment tests identified few immigrants within summering aggregations, linked migrating groups to specific summering areas, and found that some migratory corridors comprise whales from multiple subpopulations (PBAYES = 0.31:0.69). Further, dispersal is male-biased and substantial numbers of closely related whales congregate together at coastal summering areas. Stable patterns of heterogeneity between areas and consistently high proportions (~20%) of close kin (including parent-offspring) sampled up to 20 years apart within areas (G = 0.2-2.9, p>0.5) is the first direct evidence of natal philopatry to migration destinations in belugas. Using recent satellite telemetry findings on belugas we found that the spatial proximity of winter ranges has a greater influence on the degree of both individual and genetic exchange than summer ranges (rwinter-Fst-mtDNA = 0.9, rsummer-Fst-nDNA = 0.1). These findings indicate widespread natal philopatry to summering aggregation and entire migratory circuits, and provide compelling evidence that migratory culture and kinship helps maintain demographically discrete beluga stocks that can overlap in time and space.
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Affiliation(s)
- Greg O’Corry-Crowe
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida, United States of America
| | - Robert Suydam
- North Slope Borough Department of Wildlife Management, Barrow, Alaska, United States of America
| | - Lori Quakenbush
- Alaska Department of Fish and Game, Fairbanks, Alaska, United States of America
| | - Brooke Potgieter
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida, United States of America
| | - Lois Harwood
- Fisheries and Oceans Canada, Yellowknife, Northwest Territories, Canada
| | - Dennis Litovka
- Marine Mammal Laboratory, ChukotTINRO, Anadyr, Chukotka, Russia
| | - Tatiana Ferrer
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida, United States of America
| | - John Citta
- Alaska Department of Fish and Game, Fairbanks, Alaska, United States of America
| | - Vladimir Burkanov
- North Pacific Wildlife Consulting, Marine Mammal Laboratory, Seattle, Washington, United States of America
| | - Kathy Frost
- University of Alaska, School of Fisheries and Ocean Science, Kailua Kona, Hawaii, United States of America
| | - Barbara Mahoney
- National Marine Fisheries Service, Anchorage, Alaska, United States of America
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Noren SR, Poll CP, Edwards MS. Body Growth and Rapid Hematological Development Support Breath Hold of Baby Belugas (Delphinapterus leucas) during Subice Transit. Physiol Biochem Zool 2017; 91:691-704. [PMID: 29125799 DOI: 10.1086/694920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Body size and oxygen stores in the blood and muscle set breath-hold limits in marine mammals, yet these characteristics are understudied in immature cetaceans. We examined body mass and hematology from birth through adulthood in beluga whales (Delphinapterus leucas). At birth, body mass was 8% and 6% of the maximum mass recorded for adult females and males, respectively. Body mass then increased rapidly, approaching an asymptote around 12 yr for females and 18 yr for males. Interestingly, red blood cell counts, hemoglobin content, and hematocrit levels decreased after birth; this neonatal anemia was reversed as levels increased after 2 mo postpartum. Mature levels were obtained at approximately 8, 9, and 11 mo postpartum, respectively. Neonatal mean corpuscular hemoglobin also increased with ontogeny; mature levels were achieved by approximately 13 mo after birth. In contrast, mean corpuscular volume and mean corpuscular hemoglobin concentration demonstrated a significant but subtle increase throughout ontogeny. Our results indicate that postnatal maturation was required and that maturation occurred far earlier than the age at weaning (i.e., 2-3 yr postpartum). This is atypical of marine mammals, which generally achieve mature hemoglobin levels at weaning. Hematological maturation before maternal independence undoubtedly supports the prolonged breath holds of young belugas transiting under sea ice. This assessment enhances our knowledge of cetacean physiology and provides important inputs for determining age-specific dive capacity, yielding insights into age-specific flexibility to alter underwater behaviors, as will be required for future regime shifts and disturbances.
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Hill HM, Guarino S, Calvillo A, Gonzalez A, Zuniga K, Bellows C, Polasek L, Sims C. Lateralized swim positions are conserved across environments for beluga (Delphinapterus leucas) mother–calf pairs. Behav Processes 2017; 138:22-28. [DOI: 10.1016/j.beproc.2017.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 12/22/2016] [Accepted: 01/27/2017] [Indexed: 11/24/2022]
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Bădescu I, Watts DP, Katzenberg MA, Sellen DW. Alloparenting is associated with reduced maternal lactation effort and faster weaning in wild chimpanzees. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160577. [PMID: 28018647 PMCID: PMC5180145 DOI: 10.1098/rsos.160577] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/12/2016] [Indexed: 06/06/2023]
Abstract
Alloparenting, when individuals other than the mother assist with infant care, can vary between and within populations and has potential fitness costs and benefits for individuals involved. We investigated the effects of alloparenting on the speed with which infants were weaned, a potential component of maternal fitness because of how it can affect inter-birth intervals, in wild chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Uganda. We also provide, to our knowledge, the first description of alloparenting in this population and present a novel measure of the contribution of milk to infant diets through faecal stable nitrogen isotopes (δ15N). Using 42 mother-infant pairs, we tested associations of two alloparenting dimensions, natal attraction (interest in infants) and infant handling (holding, carrying), to the proportion of time mothers spent feeding and to maternal lactation effort (mean nursing rates and mother-infant δ15N differences). Neither natal attraction nor infant handling was significantly associated with feeding time. Infant handling was inversely associated with both measures of lactation effort, although natal attraction showed no association. Alloparenting may benefit mothers by enabling females to invest in their next offspring sooner through accelerated weaning. Our findings emphasize the significance of alloparenting as a flexible component of female reproductive strategies in some species.
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Affiliation(s)
- Iulia Bădescu
- Department of Anthropology, University of Toronto, Toronto, Ontario, CanadaM5S 2S2
| | - David P. Watts
- Department of Anthropology, Yale University, New Haven, CT 06511, USA
| | - M. Anne Katzenberg
- Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, CanadaT2N 1N4
| | - Daniel W. Sellen
- Department of Anthropology, University of Toronto, Toronto, Ontario, CanadaM5S 2S2
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Breton-Honeyman K, Hammill M, Furgal C, Hickie B. Inuit Knowledge of beluga whale (Delphinapterus leucas) foraging ecology in Nunavik (Arctic Quebec), Canada. CAN J ZOOL 2016. [DOI: 10.1139/cjz-2015-0259] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The beluga whale (Delphinapterus leucas (Pallas, 1776)) is expected to be influenced by changes in the environment. In Nunavik, the Arctic region of Quebec, Nunavimmiut (Inuit of Nunavik) have depended on beluga for centuries, developing an extensive understanding of the species and its ecology. Forty semidirective interviews were conducted with Inuit hunters and Elders from four Nunavik communities, who had a range of 28–47 years of beluga hunting experience. Interviews followed an ethnocartographic format and were analyzed using a mixed methods approach. Hunters most commonly reported prey species from the sculpin (Cottidae), cod (Gadidae), salmon (Salmonidae), and crustacean families; regional variations in prey and in foraging habitat were found. Hunters identified significant changes in body condition (i.e., blubber thickness), which were associated with observations about the seasonality of feeding. The timing of fat accumulation in the late fall and winter coupled with the understanding that Hudson Bay is not known as a productive area suggest alternate hypotheses to feeding for the seasonal movements exhibited by these whales. Inuit Knowledge of beluga foraging ecology presented here provides information on diet composition and seasonality of energy intake of the beluga and can be an important component of monitoring diet composition for this species into the future. An Inuttitut version of the abstract is available ( Appendix A ).
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Affiliation(s)
- K. Breton-Honeyman
- Environmental and Life Sciences Program, Trent University, Peterborough, ON K9L 0G2, Canada
- Health, Environment, and Indigenous Communities Research Group, Trent University, Peterborough, ON K9L 0G2, Canada
| | - M.O. Hammill
- Maurice-Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC G5H 3Z4, Canada
| | - C.M. Furgal
- Health, Environment, and Indigenous Communities Research Group, Trent University, Peterborough, ON K9L 0G2, Canada
- Indigenous Environmental Studies Program, Trent University, Peterborough, ON K9L 0G2, Canada
| | - B. Hickie
- Environmental and Life Sciences Program, Trent University, Peterborough, ON K9L 0G2, Canada
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22
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Noren SR, Suydam R. Navigating under sea ice promotes rapid maturation of diving physiology and performance in beluga whales. J Exp Biol 2016; 219:2828-2836. [DOI: 10.1242/jeb.143644] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/30/2016] [Indexed: 01/30/2023]
Abstract
ABSTRACT
Little is known about the postnatal development of the physiological characteristics that support breath-hold in cetaceans, despite their need to swim and dive at birth. Arctic species have the additional demand of avoiding entrapment while navigating under sea ice, where breathing holes are patchily distributed and ephemeral. This is the first investigation of the ontogeny of the biochemistry of the locomotor muscle in a year-round Arctic-dwelling cetacean (beluga whale, Delphinapterus leucas). Compared with what we know about other cetaceans, belugas are born with high myoglobin content (1.56±0.02 g 100 g−1 wet muscle mass, N=2) that matures rapidly. Myoglobin increased by 452% during the first year after birth and achieved adult levels (6.91±0.35 g 100 g−1 wet muscle mass, N=9) by 14 months postpartum. Buffering capacity was 48.88±0.69 slykes (N=2) at birth; adult levels (84.31±1.38 slykes, N=9) were also achieved by 14 months postpartum. As the oxygen stores matured, calculated aerobic dive limit more than doubled over the first year of life, undoubtedly facilitating the movements of calves under sea ice. Nonetheless, small body size theoretically continues to constrain the diving ability of newly weaned 2 year olds, as they only had 74% and 69% of the aerobic breath-hold capacity of larger adult female and male counterparts. These assessments enhance our knowledge of the biology of cetaceans and provide insight into age-specific flexibility to alter underwater behaviors, as may be required with the ongoing alterations in the Arctic marine ecosystem associated with climate change and increased anthropogenic activities.
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Affiliation(s)
- Shawn R. Noren
- Institute of Marine Science, University of California, Santa Cruz, Center for Ocean Health, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Robert Suydam
- North Slope Borough, Department of Wildlife Management, Barrow, AK 99723, USA
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