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Peter B Best - One of the best experts on this subject based on the ideXlab platform.
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the recovery of north atlantic right whales Eubalaena glacialis has been constrained by human caused mortality
Royal Society Open Science, 2018Co-Authors: Peter J Corkeron, Victoria J Rowntree, Peter B Best, Karina R. Groch, John Bannister, Philip K Hamilton, Claire Charlton, Ken P Findlay, Els Vermeulen, Richard M PaceAbstract:North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and s...
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blubber thickness in right whales Eubalaena glacialis and Eubalaena australis related with reproduction life history status and prey abundance
Marine Ecology Progress Series, 2011Co-Authors: Carolyn A. Miller, Desray Reeb, Moira W Brown, Peter B Best, Amy Ruth Knowlton, Michael J. MooreAbstract:The high variability in reproductive performance of North Atlantic right whales Eubal- aena glacialis compared to southern right whales Eubalaena australis may reflect differences in lipid reserves. Amplitude-mode ultrasound was used to measure the thickness of right whale integument (epidermis and blubber, herein referred to as blubber thickness) in E. glacialis in the Bay of Fundy, Canada for 5 summer seasons and in E. australis off the South African coast for 2 austral winter sea- sons. E. glacialis had significantly thinner blubber layers (mean ±1 SD = 12.23 ± 2.16 cm, n = 172) than E. australis (16.13 ± 3.88 cm, n = 117), suggesting differing levels of nutrition between the 2 species. Blubber was thickest in females measured 3 to 6 mo prior to the start of pregnancy (E. glacialis), thin- ner during lactation (E. glacialis, E. australis) and then thicker with time after weaning (E. glacialis). These results suggest that lipids in blubber are used as energetic support for reproduction in female right whales. Blubber thickness increased in calves during suckling (E. glacialis, E. australis) but sub - sequently decreased after weaning (E. glacialis). Juvenile and adult male E. glacialis blubber thick- nesses were compared between years of differing prey Calanus finmarchicus abundances (data from Pershing et al. 2005; ICES J Mar Sci 62:1511-1523); during a year of low prey abundance whales had significantly thinner blubber than during years of greater prey abundance. Taken together, these re- sults suggest that blubber thickness is indicative of right whale energy balance and that the marked fluctuations in North Atlantic right whale reproduction have a nutritional component.
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Yeast infection in a beached southern right whale (Eubalaena australis) neonate.
Journal of wildlife diseases, 2009Co-Authors: Marnel Mouton, Desray Reeb, Alfred Botha, Peter B BestAbstract:A female southern right whale (Eubalaena australis) neonate was found stranded on the Western Cape coast of southern Africa. Skin samples were taken the same day from three different locations on the animal’s body and stored at −20 C. Isolation through repetitive culture of these skin sections yielded a single yeast species, Candida zeylanoides. Total genomic DNA also was isolated directly from skin samples. Polymerase chain reaction analysis of the internal transcribed spacer region of the fungal ribosomal gene cluster revealed the presence of Filobasidiella neoformans var. neoformans, the teleomorphic state of Cryptococcus neoformans. Fungal infections in cetaceans seem to be limited when compared to infections caused by bacteria, viruses and parasites. However, Candida species appear to be the most common type of fungal infection associated with cetaceans. To our knowledge this is the first report of a C. zeylanoides infection in a mysticete, as well as the first report of a dual infection involving tw...
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Mitochondrial DNA Diversity and Population Structure among Southern Right Whales (Eubalaena australis)
The Journal of heredity, 2007Co-Authors: Nathalie J. Patenaude, Peter B Best, Vicky A. Portway, C. Schaeff, John Bannister, R. Payne, Vj Rowntree, Mariana Rivarola, C. Scott BakerAbstract:The population structure and mitochondrial (mt) DNA diversity of southern right whales (Eubalaena australis) are described from 146 individuals sampled on 4 winter calving grounds (Argentina, South Africa, Western Australia, and the New Zealand sub-Antarctic) and 2 summer feeding grounds (South Georgia and south of Western Australia). Based on a consensus region of 275 base pairs of the mtDNA control region, 37 variable sites defined 37 unique haplotypes, of which only one was shared between regional samples of the Indo-Pacific and South Atlantic Oceans. Phylogenetic reconstruction of the southern right whale haplotypes revealed 2 distinct clades that differed significantly in frequencies between oceans. An analysis of molecular variance confirmed significant overall differentiation among the 4 calving grounds at both the haplotype and the nucleotype levels (FST 5 0.159; UST5 0.238; P , 0.001). Haplotype diversity was significantly lower in the Indo-Pacific (h 5 0.701 ± 0.037) compared with the South Atlantic (h 5 0.948 ± 0.013), despite a longer history of exploitation and larger catches in the South Atlantic. In fact, the haplotype diversity in the Indo-Pacific basin was similar to that of the North Atlantic right whale that currently numbers about 300 animals. Multidimensional scaling of genetic differentiation suggests that gene flow occurred primarily between adjacent calving grounds within an ocean basin, with mixing of lineages from different calving grounds occurring on feeding grounds.
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Structure of the integument of southern right whales, Eubalaena australis
Anatomical record (Hoboken N.J. : 2007), 2007Co-Authors: Desray Reeb, Peter B Best, Susan H. KidsonAbstract:Skin (integument) anatomy reflects adaptations to particular environments. It is hypothesized that cetacean (whale) integument will show unique anatomical adaptations to an aquatic environment, particularly regarding differences in temperature, density, and pressure. In this study, the gross and histological structure of the southern right whale integument is described and compared with terrestrial mammals and previous descriptions of mysticete (baleen whale) and odontocete (toothed whale) species. Samples were taken of the integument of 98 free-swimming southern right whales, Eubalaena australis, and examined by both light and electron microscopy. Results show that three epidermal layers are present, with the stratum corneum being parakeratotic in nature. As in bowhead whales, southern right whales possess an acanthotic epidermis and a notably thick hypodermis, with epidermal rods and extensive papillomatosis. However, unlike bowhead whales, southern right whales possess an uninterrupted hypodermal layer. Surprisingly, the integument of balaenids (right and bowhead mysticetes) in general is more like that of odontocetes than that of the more closely related balaenopterids (rorqual mysticetes). Similarities to odontocetes were found specifically in the collagen fibers in a fat-free zone of the reticular dermal layer and the elastic fibers in the dermal and hypodermal layers. Callosities, a distinctive feature of this genus, have a slightly thicker stratum corneum and are usually associated with hairs that have innervated and vascularized follicles. These hairs may function as vibrissae, thus aiding in aquatic foraging by allowing rapid detection of changes in prey density. Although the thick insulatory integument makes right whales bulky and slow-moving, it is an adaptation for living in cold water. Epidermal thickness, presence of epidermal rods, and callosities may act as barriers against mechanical injury from bodily contact with conspecifics or hard surfaces in the environment (e.g., rocks, ice).
Victoria J Rowntree - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic debris in the digestive tract of a southern right whale (Eubalaena australis) stranded in Golfo Nuevo, Argentina.
Marine pollution bulletin, 2020Co-Authors: Lucia Alzugaray, Victoria J Rowntree, Lucas Beltramino, Mariano Sironi, M. Di Martino, Marcela UhartAbstract:Abstract Over the past fifty years, interactions between anthropogenic debris and a wide range of marine species have increased. In cetaceans, the most frequent interactions have occurred through ingestion and/or entanglement, with results ranging from minor injuries to death in affected animals. While debris ingestion is widely documented in odontocetes, records are scarcer in mysticetes. This study describes the finding of plastic litter in the digestive tract of a southern right whale (Eubalaena australis) juvenile male, which was found dead on the shores of Golfo Nuevo, Chubut, Argentina in 2014. During the examination of intestinal contents, anthropogenic waste was found and classified as macro-debris (25 mm-1 m). Although this whale likely died of causes not related to this finding, it is the first record of anthropogenic debris ingestion for this species. This event adds information about the potential impact of human-made debris on a variety of aquatic species and ecosystems.
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the recovery of north atlantic right whales Eubalaena glacialis has been constrained by human caused mortality
Royal Society Open Science, 2018Co-Authors: Peter J Corkeron, Victoria J Rowntree, Peter B Best, Karina R. Groch, John Bannister, Philip K Hamilton, Claire Charlton, Ken P Findlay, Els Vermeulen, Richard M PaceAbstract:North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and s...
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lifetime glucocorticoid profiles in baleen of right whale calves potential relationships to chronic stress of repeated wounding by kelp gulls
Conservation Physiology, 2018Co-Authors: Alejandro Fernandez Ajo, Victoria J Rowntree, Marcela Uhart, Mariano Sironi, Kathleen E Hunt, Carina F Maron, Matias Di Martino, Loren C BuckAbstract:Baleen tissue accumulates stress hormones (glucocorticoids, GC) as it grows, along with other adrenal, gonadal and thyroid hormones. The hormones are deposited in a linear fashion such that a single plate of baleen allows retrospective assessment and evaluation of long-term trends in the whales' physiological condition. In whale calves, a single piece of baleen contains hormones deposited across the lifespan of the animal, with the tip of the baleen representing prenatally grown baleen. This suggests that baleen recovered from stranded carcasses of whale calves could be used to examine lifetime patterns of stress physiology. Here we report lifetime profiles of cortisol and corticosterone in baleen of a North Atlantic right whale ('NARW'-Eubalaena glacialis) calf that died from a vessel strike, as well as four southern right whale ('SRW'-Eubalaena australis) calves that were found dead with varying severity of chronic wounding from Kelp Gull (Larus dominicanus) attacks. In all five calves, prenatally grown baleen exhibited a distinctive profile of elevated glucocorticoids that declined shortly before birth, similar to GC profiles reported from baleen of pregnant females. After birth, GC profiles in calf baleen corresponded with the degree of wounding. The NARW calf and two SRW calves with no or few gull wounds had relatively low and constant GC content throughout life, while two SRW calves with high numbers of gull wounds had pronounced elevations in baleen GC content in postnatal baleen followed by a precipitous decline shortly before death, a profile suggestive of prolonged chronic stress. Baleen samples may present a promising and valuable tool for defining the baseline physiology of whale calves and may prove useful for addressing conservation-relevant questions such as distinguishing acute from chronic stress and, potentially, determining cause of death.
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southern right whale Eubalaena australis calf mortality at peninsula valdes argentina are harmful algal blooms to blame
Marine Mammal Science, 2016Co-Authors: Cara Wilson, Victoria J Rowntree, Mónica Susana Hoffmeyer, Spencer E. Fire, Norma Santinelli, Soledad Díaz Ovejero, Viviana A Sastre, Valeria C DagostinoAbstract:Peninsula Valdes (PV) in Argentina is an important calving ground for southern right whales (SRWs, Eubalaena australis). Since 2005, right whale mortality has increased at PV, with most of the deaths (~90%) being calves <3 mo old. We investigated the potential involvement of harmful algal blooms (HABs) in these deaths by examining data that include: timing of the SRW deaths, biotoxins in samples from dead SRWs, abundances of the diatom, Pseudo-nitzschia spp., and the dinoflagellate, Alexandrium tamarense, shellfish harvesting closure dates, seasonal availability of whale prey at PV and satellite chlorophyll data. Evidence of the whales' exposure to HAB toxins includes trace levels of paralytic shellfish toxins (PSTs) and domoic acid (DA) in tissues of some dead whales, and fragments of Pseudo-nitzschia spp. frustules in whale feces. Additionally, whales are present at PV during both closures of the shellfish industry (due to high levels of PSTs) and periods with high levels of Pseudo-nitzschia spp. and A. tamarense. There is a positive statistical relationship between monthly Pseudo-nitzschia densities (but not A. tamarense) and calf deaths in both gulfs of PV.
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Global climate drives southern right whale (Eubalaena australis) population dynamics
Biology letters, 2006Co-Authors: Russell Leaper, Victoria J Rowntree, Justin Cooke, Phil Trathan, Keith Reid, Roger PayneAbstract:Sea surface temperature (SST) time-series from the southwest Atlantic and the El Nino 4 region in the western Pacific were compared to an index of annual calving success of the southern right whale (Eubalaena australis) breeding in Argentina. There was a strong relationship between right whale calving output and SST anomalies at South Georgia in the autumn of the previous year and also with mean El Nino 4 SST anomalies delayed by 6 years. These results extend similar observations from other krill predators and show clear linkages between global climate signals and the biological processes affecting whale population dynamics.
Scott D Kraus - One of the best experts on this subject based on the ideXlab platform.
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future directions in Eubalaena spp comparative research to inform conservation
Frontiers in Marine Science, 2019Co-Authors: Robert Harcourt, Scott D Kraus, Julie Van Der Hoop, Emma L. CarrollAbstract:All three extant right whales (Eubalaena australis (Southern; SRW), glacialis (North Atlantic; NARW), and japonica (North Pacific; NPRW)) were heavily exploited, and the status of the two northern hemisphere species remains precarious. Limited gains made by the NARW have been reversed and urgent changes to management approaches are needed to avert extinction. By contrast, some SRW populations are recovering. Given their close phylogenetic relationship, morphological, demographic, and ecological similarities, the contrasting recovery rates suggest a comparative approach. 1. Recovery Right whales were protected in 1931, but NARW, NPRW and some SRW populations have barely recovered from whaling, while others are doing well. Are these differences a legacy of extreme depletion (e.g., loss of genetic diversity and cultural knowledge) or primarily due to anthropogenic factors (e.g. ship strike and fisheries entanglement). If modern anthropogenic threats are not affecting remote SRW populations, inform on NARW and NPRW? 2. Linking individuals to population level responses In the context of life history strategies strong links exist between reproductive indices and environmental conditions. Tracking survival, reproduction and other demographic parameters, and their population-level consequences, is possible with Individual identification. Robust life-history analyses link demography with environmental conditions, potentially teasing out influencing factors. 3. Adapting to shifting resources Recent reproductive declines in NARW appear linked to changing food resources and prey phenology. We know some large-scale movement patterns for NARW and a few SRW populations, we know little of mesoscale movements. For NPRW and some SRW populations, even broad-scale movements are poorly understood. In the face of climate change, can methodological advances help identify distributional and migratory responses? 4. Emergent diseases and the vulnerability of populations under stress Marine mammals are vulnerable to infectious diseases, particularly when subjected to stressors such as fishing gear entanglements, acoustic disturbance, and prey shortages. New tools to assess large whale health include body condition imaging, viromes, microbiomes, and stress hormones. 5. Comparative synthesis and cumulative effects A good cumulative effects analytical approach is urgently required, otherwise each stressor is managed in isolation, limiting efficacy. We propose a comparative synthesis to inform future cumulative effect analyses and outline future research priorities.
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monitoring north atlantic right whale Eubalaena glacialis entanglement rates a 30 yr retrospective
Marine Ecology Progress Series, 2012Co-Authors: Amy R Knowlton, Heather M Pettis, Philip K Hamilton, Marilyn K Marx, Scott D KrausAbstract:Entanglement in non-mobile fishing gear has been identified as one of the leading causes of mortality in North Atlantic right whales Eubalaena glacialis. To investigate this issue further, all available photographs of right whales taken from 1980 to 2009 were examined for evidence of entanglement with gear used in fisheries based on presence of rope or netting on the whale or scars inferred to have been caused by an encounter with rope. Photographs of 626 individual whales were assessed and 1032 unique entanglement events were documented. Of the 626 animals, 519 (82.9%) had been entangled at least once and 306 of the 519 (59.0%) had been entangled more than once. Males and females were entangled at similar rates. Juveniles were entangled at a higher rate than adults. On average, 25.9% of adequately photographed animals acquired new wounds or scars from fishing gear annually with no significant trend over time detected. However, the annual percentage of animals observed with rope on the body increased significantly during the study period, suggesting that it is becoming more difficult for whales to free themselves completely from fishing gear. Such high annual rates of entanglement remain a serious conservation concern for right whales because entanglements can have both lethal and sub-lethal effects. Federally required changes to fixed-gear fisheries in US waters have not reduced serious injuries and mortality to legally required levels. Here we show how documenting various annual rates of entanglement can monitor progress and impacts that fishing gear regula- tions may have on right whale recovery.
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analysis of fecal glucocorticoids in the north atlantic right whale Eubalaena glacialis
General and Comparative Endocrinology, 2006Co-Authors: Kathleen E Hunt, Rosalind M Rolland, Scott D Kraus, Samuel K WasserAbstract:Very little is known about the endocrinology of the baleen whales. The highly endangered North Atlantic right whale (NARW; Eubalaena glacialis) is a good model species, because most NARW individuals are photo-identiWed with known histories. We used an 125 I corticosterone assay, shown to reliably measure cortisol metabolites, to determine glucocorticoid metabolite concentrations in 177 NARW fecal samples collected between 1999‐2004 in the Bay of Fundy, Canada. Fecal glucocorticoid metabolite concentrations varied signiWcantly with sex and reproductive category, being highest in pregnant females (mean §SE: 238.14 §74.37 ng/g) and mature males (71.6 §11.36), intermediate in lactating females (39.33 §5.82), and lower in non-reproducing females (23.11 §4.25) and immature males (34.33 §5.01) and females (14.0 §0.41). One case also suggests that glucocorticoids rise markedly in response to severe entanglement in Wshing lines. Whales with fecal glucocorticoid content over 100 ng/g (termed “high-cort” samples) were rare, and included most pregnant females, some mature males, a fatally entangled whale, and several very young animals. Glucocorticoid concentrations were highly correlated with androgen concentrations in males and pregnant females. We analyzed the elution proWles of glucocorticoid and androgen metabolites in 13 samples with high-performance liquid chromatography (HPLC) to determine the extent to which androgen metabolites cross-react with our glucocorticoid assay. Males, pregnant females, non-pregnant females, and “high-cort” whales each had distinctly diVerent immunoreactive HPLC proWles of glucocorticoid and androgen metabolites. A major glucocorticoid metabolite was prominent in all “high-cort” whales including the fatally entangled whale. The major fecal androgen was not testosterone but was instead a more nonpolar steroid (possibly dihydrotestosterone), which may be diagnostic of males. Androgen metabolites showed only minor cross-reactivity to our glucocorticoid assay, having a slight inXuence on glucocorticoid results in particular individuals. We conclude that fecal glucocorticoid analysis appears to be a useful measure of adrenal activity and reproductive condition for NARW. ! 2006 Published by Elsevier Inc.
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the gunshot sound produced by male north atlantic right whales Eubalaena glacialis and its potential function in reproductive advertisement
Marine Mammal Science, 2005Co-Authors: Susan E Parks, Philip K Hamilton, Scott D Kraus, Peter L TyackAbstract:North Atlantic right whales (Eubalaena glacialis) make a short, distinctive broadband sound that is produced internally called a Gunshot sound. This sound has been recorded in the Bay of Fundy, Canada from both single whales (n= 9) and social surface active groups (n=49). Those single whales producing Gunshot sounds whose sex could be determined (n= 9) were all mature males. Gunshot sounds were produced as part of a stereotyped behavioral sequence by these individuals, including frequent head-lifts and flipper slapping at the surface. In surface active groups, Gunshot sounds were commonly recorded when males were present in the group. The rate of production of Gunshot sounds was weakly correlated with the total number of males present in the group. Given the behavioral context of Gunshot sound production, and production of the sound only by male whales, Gunshots may function in a reproductive context as an advertisement signal to attract females, an agonistic signal directed toward other males, or a combination of the two functions.
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assessing reproductive status of right whales Eubalaena glacialis using fecal hormone metabolites
General and Comparative Endocrinology, 2005Co-Authors: Rosalind M Rolland, Scott D Kraus, Kathleen E Hunt, Samuel K WasserAbstract:Abstract Long-term studies of the endangered North Atlantic right whale, Eubalaena glacialis , have revealed declining reproductive parameters over the past two decades, threatening recovery of this small population if current trends continue. Little is known about right whale reproductive physiology, and investigating this reproductive decline has been limited by a lack of non-lethal methods for assessing reproductive status (e.g., sexual maturation, ovarian activity, pregnancy, lactation, and reproductive senescence) in free-swimming whales. This paper describes validation of existing radioimmunoassay techniques to study reproduction in right whales by measuring estrogens, progestins, androgens, and their related metabolites in fecal samples. Over the past decade fecal steroid hormone assays have been used to assess reproductive status and function in a wide range of terrestrial wildlife species, but this is the first application of this methodology in wild cetaceans. Analysis of fecal hormone metabolite levels in combination with life history data from photographically identified whales shows that this non-invasive method can be used to determine gender, detect pregnancy and lactation, and to assess age at sexual maturity in right whales and potentially other endangered whale populations.
Peter T Madsen - One of the best experts on this subject based on the ideXlab platform.
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acoustic crypsis in southern right whale mother calf pairs infrequent low output calls to avoid predation
The Journal of Experimental Biology, 2019Co-Authors: Mia L K Nielsen, Simone K A Videsen, Fredrik Christiansen, Lars Bejder, Peter T MadsenAbstract:ABSTRACT Southern right whales ( Eubalaena australis ) invest substantial amounts of energy in their calves, while facing the risk of having them predated upon by eavesdropping killer whales ( Orcinus orca ). We tested the hypothesis that southern right whale mother–calf pairs employ acoustic crypsis to reduce acoustic detectability by such predators. Specifically, we deployed multi-sensor DTAGs on nine lactating whales for a total of 62.9 h in a Western Australian breeding ground, and used a SoundTrap to estimate the concomitant acoustic background noise. Vocalisations were recorded at low rates of −1 (1 call per dive) and at low received levels between 123±8 and 134±10 dB re. 1 µPa RMS depending on call type. We conclude that such acoustic crypsis in southern right whales and other baleen whales decreases the risk of alerting potential predators and hence jeopardizing a substantial energetic investment by the mother.
Bradley N White - One of the best experts on this subject based on the ideXlab platform.
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evidence of a north atlantic right whale Eubalaena glacialis mating ground
Endangered Species Research, 2013Co-Authors: Timothy V N Cole, Philip K Hamilton, Richard M Pace, Bradley N White, Allison Henry, Peter Duley, Timothy R FrasierAbstract:The location of mating grounds used by Endangered North Atlantic right whales Eubalaena glacialis has eluded discovery despite centuries of whaling and decades of marine mammal surveys. If this species' gestation duration is similar to the closely related southern right whale E. australis, then conception for the North Atlantic right whale occurs in the boreal winter. Between 2002 and 2008, aerial surveys identified half the North Atlantic population in the central Gulf of Maine between November and January. Generalized linear models indicated that signifi- cantly higher proportions of both known fathers and conceptive females were present in this region compared to most other areas seasonally inhabited by right whales. Their presence in the central Gulf of Maine during the estimated conception period strongly suggests that this region is a mating ground for the species. Roseway Basin, on the southwestern Scotian Shelf, also had high proportions of reproductive whales and may be the site of some conceptions if right whale gesta- tion extends to 14 mo.
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genetic analysis of 16th century whale bones prompts a revision of the impact of basque whaling on right and bowhead whales in the western north atlantic
Canadian Journal of Zoology, 2004Co-Authors: Toolika Rastogi, Moira W Brown, Timothy R Frasier, Brenna A Mcleod, Robert Grenier, Stephen L Cumbaa, Jeya Nadarajah, Bradley N WhiteAbstract:The North Atlantic right whale, Eubalaena glacialis (Muller, 1776), is one of the world's most endangered large cetaceans. It is widely believed that Basque whalers caused the most dramatic decline of this species in the western North Atlantic during the early-16th and 17th centuries. Previous osteological analysis of 17 historic bones suggested that 50% of the Basque harvest consisted of right whales and 50% of bowhead whales, Balaena mysticetus L., 1758. This 50:50 ratio has been used to estimate pre-exploitation population size, which has subsequently formed the basis of recovery goals and plans for the North Atlantic right whale. Genetic analysis of 21 bones, 13 identified as right whales and 8 as bowhead whales through osteological examination, indicates that in fact only 1 bone was a right whale and 20 were bowhead whales. Additionally, preliminary microsatellite analyses of this specimen are not consistent with the hypothesis that whaling resulted in the low genetic variation found in this species ...
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world wide genetic differentiation of Eubalaena questioning the number of right whale species
Molecular Ecology, 2000Co-Authors: Howard C Rosenbaum, Moira W Brown, Robert L. Brownell, Vicky A. Portway, C. Schaeff, Bradley N White, S Malik, L A Pastene, Nathalie J. PatenaudeAbstract:Few studies have examined systematic relationships of right whales (Eubalaena spp.) since the original species descriptions, even though they are one of the most endangered large whales. Little morphological evidence exists to support the current species designations for Eubalaena glacialis in the northern hemisphere and E. australis in the southern hemisphere. Differences in migratory behaviour or antitropical distribution between right whales in each hemisphere are considered a barrier to gene flow and maintain the current species distinctions and geographical populations. However, these distinctions between populations have remained controversial and no study has included an analysis of all right whales from the three major ocean basins. To address issues of genetic differentiation and relationships among right whales, we have compiled a database of mitochondrial DNA control region sequences from right whales representing populations in all three ocean basins that consist of: western North Atlantic E. glacialis, multiple geographically distributed populations of E. australis and the first molecular analysis of historical and recent samples of E. glacialis from the western and eastern North Pacific Ocean. Diagnostic characters, as well as phylogenetic and phylogeographic analyses, support the possibility that three distinct maternal lineages exist in right whales, with North Pacific E. glacialis being more closely related to E. australis than to North Atlantic E. glacialis. Our genetic results provide unequivocal character support for the two usually recognized species and a third distinct genetic lineage in the North Pacific under the Phylogenetic Species Concept, as well as levels of genetic diversity among right whales world-wide.
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assessment of mitochondrial dna structuring and nursery use in the north atlantic right whale Eubalaena glacialis
Canadian Journal of Zoology, 1999Co-Authors: S Malik, Moira W Brown, Philip K Hamilton, Amy R Knowlton, Scott D Kraus, Bradley N WhiteAbstract:The North Atlantic right whale (Eubalaena glacialis) inhabits five areas along the east coast of North America at different times of the year. During 17 years of field observations, it has been found that only 59% of the newborn calves are brought to the Bay of Fundy nursery area. To examine whether this is because of population structuring, the mitochondrial DNA (mtDNA) control region haplotypes were determined for 269 individuals. Seven polymorphic sites were found to define five haplotypes. Calves were divided into two groups based on whether or not they were brought to the Bay of Fundy nursery. Significant genetic structuring of mitochondrial haplotypes was found between these groups (p = 0.002). Mothers that have had more than three calves demonstrated significant fidelity (p = 0.005) to the Bay of Fundy, suggesting that philopatry is the basis for the genetic structuring. Although this study clearly identifies the existence of two subpopulations and an alternative nursery area(s), the location(s) of the alternative area(s) is unclear and remains an important issue for the conservation of the species.
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assessment of the population structure of western north atlantic right whales Eubalaena glacialis based on sighting and mtdna data
Canadian Journal of Zoology, 1993Co-Authors: Catherine M Schaeff, Moira W Brown, Scott D Kraus, Bradley N WhiteAbstract:Photoidentifications and 11 years of sighting data revealed that only two-thirds of the western North Atlantic right whale (Eubalaena glacialis) reproductive females took their calves to the Bay of...
