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1.
Proc Biol Sci ; 287(1925): 20192964, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32315590

RESUMO

The Arctic is warming at an unprecedented rate, with unknown consequences for endemic fauna. However, Earth has experienced severe climatic oscillations in the past, and understanding how species responded to them might provide insight into their resilience to near-future climatic predictions. Little is known about the responses of Arctic marine mammals to past climatic shifts, but narwhals (Monodon monoceros) are considered one of the endemic Arctic species most vulnerable to environmental change. Here, we analyse 121 complete mitochondrial genomes from narwhals sampled across their range and use them in combination with species distribution models to elucidate the influence of past and ongoing climatic shifts on their population structure and demographic history. We find low levels of genetic diversity and limited geographic structuring of genetic clades. We show that narwhals experienced a long-term low effective population size, which increased after the Last Glacial Maximum, when the amount of suitable habitat expanded. Similar post-glacial habitat release has been a key driver of population size expansion of other polar marine predators. Our analyses indicate that habitat availability has been critical to the success of narwhals, raising concerns for their fate in an increasingly warming Arctic.


Assuntos
Mudança Climática , Filogeografia , Baleias/psicologia , Animais , Regiões Árticas , Demografia , Ecossistema , Genoma Mitocondrial
2.
Proc Biol Sci ; 287(1921): 20200070, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32070257

RESUMO

Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with multiple beaked whale (BW) mass stranding events. Multinational naval ASW exercises have used MFAS offshore of the Mariana Archipelago semi-annually since 2006. We report BW and MFAS acoustic activity near the islands of Saipan and Tinian from March 2010 to November 2014. Signals from Cuvier's (Ziphius cavirostris) and Blainville's beaked whales (Mesoplodon densirostris), and a third unidentified BW species, were detected throughout the recording period. Both recorders documented MFAS on 21 August 2011 before two Cuvier's beaked whales stranded on 22-23 August 2011. We compared the history of known naval operations and BW strandings from the Mariana Archipelago to consider potential threats to BW populations. Eight BW stranding events between June 2006 and January 2019 each included one to three animals. Half of these strandings occurred during or within 6 days after naval activities, and this co-occurrence is highly significant. We highlight strandings of individual BWs can be associated with ASW, and emphasize the value of ongoing passive acoustic monitoring, especially for beaked whales that are difficult to visually detect at sea. We strongly recommend more visual monitoring efforts, at sea and along coastlines, for stranded cetaceans before, during and after naval exercises.


Assuntos
Navios , Baleias , Acústica , Animais , Mergulho , Micronésia , Som
3.
PLoS One ; 15(2): e0229085, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084174

RESUMO

The sodium iodide symporter (NIS) transports iodide, which is necessary for thyroid hormone production. NIS also transports other monovalent anions such as tetrafluoroborate (BF4-), pertechnetate (TcO4-), and thiocyanate (SCN-), and is competitively inhibited by perchlorate (ClO4-). However, the mechanisms of substrate selectivity and inhibitor sensitivity are poorly understood. Here, a comparative approach was taken to determine whether naturally evolved NIS proteins exhibit variability in their substrate transport properties. The NIS proteins of thirteen animal species were initially assessed, and three species from environments with differing iodide availability, freshwater species Danio rerio (zebrafish), saltwater species Balaenoptera acutorostrata scammoni (minke whale), and non-aquatic mammalian species Homo sapiens (human) were studied in detail. NIS genes from each of these species were lentivirally transduced into HeLa cells, which were then characterized using radioisotope uptake assays, 125I- competitive substrate uptake assays, and kinetic assays. Homology models of human, minke whale and zebrafish NIS were used to evaluate sequence-dependent impact on the organization of Na+ and I- binding pockets. Whereas each of the three proteins that were analyzed in detail concentrated iodide to a similar degree, their sensitivity to perchlorate inhibition varied significantly: minke whale NIS was the least impacted by perchlorate inhibition (IC50 = 4.599 µM), zebrafish NIS was highly sensitive (IC50 = 0.081 µM), and human NIS showed intermediate sensitivity (IC50 = 1.566 µM). Further studies with fifteen additional substrates and inhibitors revealed similar patterns of iodide uptake inhibition, though the degree of 125I- uptake inhibition varied with each compound. Kinetic analysis revealed whale NIS had the lowest Km-I and the highest Vmax-I. Conversely, zebrafish NIS had the highest Km and lowest Vmax. Again, human NIS was intermediate. Molecular modeling revealed a high degree of conservation in the putative ion binding pockets of NIS proteins from different species, which suggests the residues responsible for the observed differences in substrate selectivity lie elsewhere in the protein. Ongoing studies are focusing on residues in the extracellular loops of NIS as determinants of anion specificity. These data demonstrate significant transport differences between the NIS proteins of different species, which may be influenced by the unique physiological needs of each organism. Our results also identify naturally-existing NIS proteins with significant variability in substrate transport kinetics and inhibitor sensitivity, which suggest that the affinity and selectivity of NIS for certain substrates can be altered for biotechnological and clinical applications. Further examination of interspecies differences may improve understanding of the substrate transport mechanism.


Assuntos
Boratos/metabolismo , Animais , Linhagem Celular , Células HeLa , Humanos , Cinética , Lentivirus/genética , Percloratos/metabolismo , Simportadores/metabolismo , Tiocianatos/metabolismo , Baleias , Peixe-Zebra
5.
Sci Total Environ ; 713: 136643, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955104

RESUMO

Collisions between ships and whales raise environmental, safety, and economic concerns. The management of whale-ship collisions, however, lacks a holistic approach, unlike the management of other types of wildlife-vehicle collisions, which have been more standardized for several years now. In particular, safety and economic factors are routinely omitted in the assessment of proposed mitigation solutions to ship strikes, possibly leading to under-compliance and a lack of acceptance from the stakeholders. In this study, we estimate the probability of ship damage due to a whale-ship collision. While the probability of damage is low, the costs could be important, suggesting that property damages are significant enough to be taken into consideration when assessing solutions. Lessons learned from other types of wildlife-vehicle collisions suggest that the whale-ship collision should be managed as wildlife-aircraft collisions. For several years, the International Civil Aviation Organization (ICAO) manages collisions between aircrafts and wildlife at the international level. We advocate that its United Nations counterpart, namely the International Maritime Organization (IMO), get more involved in the whale-ship collision management. Further research is needed to more precisely quantify the costs incurred to ships from damages caused by whale-ship collisions.


Assuntos
Navios , Baleias , Animais , Animais Selvagens , Probabilidade
8.
Glob Chang Biol ; 26(2): 734-745, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31729818

RESUMO

The North Atlantic right whale (Eubalaena glacialis) is one of the world's most highly endangered baleen whales, with approximately 400-450 individuals remaining. Massachusetts Bay (MB) and Cape Cod Bay (CCB) together comprise one of seven areas in the Gulf of Maine where right whales seasonally congregate. Here, we report on acoustically detected presence of right whales in MB over a nearly 6 year period, July 2007-April 2013, a time of both rapid ocean warming throughout the Gulf of Maine and apparent changes in right whale migratory dynamics. We applied an automated detection algorithm to assess hourly presence of right whale "up-calls" in recordings from a 19-channel acoustic array covering approximately 4,000 km2 in MB. Over the survey, up-calls were detected in 95% of 8 day periods. In each year, as expected, we observed a "peak season" of elevated up-call detections in late winter and early spring corresponding to the season when right whales congregate to feed in CCB. However, we also saw an increase in right whale occurrence during time periods thought to be part of the "off-season." With the exception of 2009-2010, when acoustic presence was unusually low, the mean percent of hours in which up-calls were detected increased every year, both during the peak season (from 38% in 2008 to 70% in 2012), and during the summer-fall season (from 2% in 2007 to 13% in 2012). Over the entire study, the peak season start date varied between 17 January and 26 February. Changes in right whale phenology in MB likely reflect broadscale changes in habitat use in other areas within the species range. This study demonstrates the value of continuous long-term survey datasets to detect and quantify shifts in cetacean habitat use as environmental conditions change and the long-term continued survival of right whales remains uncertain.


Assuntos
Baías , Baleias , Animais , Oceano Atlântico , Ecossistema , Maine , Massachusetts
9.
Mar Pollut Bull ; 150: 110595, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31669712

RESUMO

Pygmy sperm whales, Kogia breviceps (Kogiidae), are a small cetacean that inhabits Mesopelagic regions near the continental shelf. In this study we present record of plastic ingestion by K. breviceps in Brazil. In August 2010 on the coast of Rio Grande do Sul, a carcass was found showing evidences of interaction with fishing nets. The stomach content was collected for the analysis of food items, but the presence of four plastics weighing 55.9 g was found. In addition, the analysis of food items revealed the presence of the fish Merluccius hubbsi, which is an intensely explored species by fisheries activities in southern Brazil. Merluccius sp. is common in the diet of K. breviceps in several regions of the planet. This work shows that in southern Brazil, K. breviceps suffers intense impact of both ingestion of anthropic material and fisheries, and so must be closely monitored.


Assuntos
Monitoramento Ambiental , Pesqueiros , Resíduos , Baleias/fisiologia , Animais , Brasil , Humanos , Plásticos
10.
Ambio ; 49(1): 173-186, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31055794

RESUMO

Toothed whales (odontocetes) feeding on fish caught on hooks in longline fisheries is a growing issue worldwide. The substantial impacts that this behaviour, called depredation, can have on the fishing economy, fish stocks and odontocetes populations, raise a critical need for mitigation solutions to be developed. However, information on when, where and how odontocete depredation occurs underwater is still limited, especially in demersal longline fisheries (fishing gear set on the seafloor). In the present study, we investigated depredation by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus) on demersal longlines in the French Patagonian toothfish fishery (Southern Ocean). Using a combination of animal-borne behavioural and longline-attached data loggers, we demonstrated that both species are able to depredate longlines on the seafloor. This study, therefore, suggests that odontocetes whales-longline interaction events at depth may be unrecorded when assessing depredation rates from surface observations during hauling phases only. This result has implications for the management of fisheries facing similar depredation issues as underestimated depredation rates may result in unaccounted fish mortality in fish-stock assessments. Therefore, while further research should be conducted to assess the extent of deep-sea whale-longline interaction events during soaking, the evidence that depredation can occur at any time during the whole fishing process as brought out by this study should be considered in future developments of mitigation solutions to the issue.


Assuntos
Cachalote , Baleias , Animais , Comportamento Animal , Pesqueiros
11.
PLoS One ; 14(12): e0225391, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31825956

RESUMO

Aegicetus gehennae is a new African protocetid whale based on a partial skull with much of an associated postcranial skeleton. The type specimen, Egyptian Geological Museum, Cairo [CGM] 60584, was found near the base of the early-Priabonian-age (earliest late Eocene) Gehannam Formation of the Wadi Al Hitan World Heritage Site in Egypt. The cranium is distinctive in having ventrally-deflected exoccipitals. The vertebral column is complete from cervical C1 through caudal Ca9, with a vertebral formula of 7:15:4:4:9+, representing, respectively, the number of cervical, thoracic, lumbar, sacral, and caudal vertebrae. CGM 60584 has two more rib-bearing thoracic vertebrae than other known protocetids, and two fewer lumbars. Sacral centra are unfused, and there is no defined auricular surface on the ilium. Thus there was no weight-bearing sacroiliac joint. The sternum is distinctive in being exceptionally broad and flat. The body weight of CGM 60584, a putative male, is estimated to have been about 890 kg in life. Long bones of the fore and hind limbs are shorter than expected for a protocetid of this size. Bones of the manus are similar in length and more robust compared to those of the pes. A log vertebral length profile for CGM 60584 parallels that of middle Eocene Maiacetus inuus through the anterior and middle thorax, but more posterior vertebrae are proportionally longer. Vertebral elongation, loss of a sacroiliac articulation, and hind limb reduction indicate that Aegicetus gehennae was more fully aquatic and less specialized as a foot-powered swimmer than earlier protocetids. It is doubtful that A. gehennae had a tail fluke, and the caudal flattening known for basilosaurids is shorter relative to vertebral column length than flattening associated with a fluke in any modern whale. Late protocetids and basilosaurids had relatively long skeletons, longer than those known earlier and later, and the middle-to-late Eocene transition from foot-powered to tail-powered swimming seemingly involved some form of mid-body-and-tail undulation.


Assuntos
Cetáceos , Natação/fisiologia , Cauda/anatomia & histologia , Cauda/fisiologia , Animais , Evolução Biológica , Egito , Fósseis , Crânio/anatomia & histologia , Coluna Vertebral/anatomia & histologia , Baleias
12.
Science ; 366(6471): 1316-1317, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31831660
13.
Science ; 366(6471): 1367-1372, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31831666

RESUMO

The largest animals are marine filter feeders, but the underlying mechanism of their large size remains unexplained. We measured feeding performance and prey quality to demonstrate how whale gigantism is driven by the interplay of prey abundance and harvesting mechanisms that increase prey capture rates and energy intake. The foraging efficiency of toothed whales that feed on single prey is constrained by the abundance of large prey, whereas filter-feeding baleen whales seasonally exploit vast swarms of small prey at high efficiencies. Given temporally and spatially aggregated prey, filter feeding provides an evolutionary pathway to extremes in body size that are not available to lineages that must feed on one prey at a time. Maximum size in filter feeders is likely constrained by prey availability across space and time.


Assuntos
Tamanho Corporal , Cadeia Alimentar , Baleias/anatomia & histologia , Baleias/fisiologia , Animais , Evolução Biológica , Biomassa , Ingestão de Energia , Euphausiacea , Comportamento Alimentar , Oceanos e Mares
15.
PLoS One ; 14(12): e0226206, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841529

RESUMO

Since the work of Tower in the 1950s, we have come to expect lower neuron density in the cerebral cortex of larger brains. We studied dolphin brains varying from 783 to 6215g. As expected, average neuron density in four areas of cortex decreased from the smallest to the largest brain. Despite having a lower neuron density than smaller dolphins, the killer whale has more gray matter and more cortical neurons than any mammal, including humans. To begin a study of non-dolphin toothed whales, we measured a 596g brain of a pygmy sperm whale and a 2004g brain of a Cuvier's beaked whale. We compared neuron density of Nissl stained cortex of these two brains with those of the dolphins. Non-dolphin brains had lower neuron densities compared to all of the dolphins, even the 6215g brain. The beaked whale and pygmy sperm whale we studied dive deeper and for much longer periods than the dolphins. For example, the beaked whale may dive for more than an hour, and the pygmy sperm whale more than a half hour. In contrast, the dolphins we studied limit dives to five or 10 minutes. Brain metabolism may be one feature limiting dolphin dives. The brain consumes an oversized share of oxygen available to the body. The most oxygen is used by the cortex and cerebellar gray matter. The dolphins have larger brains, larger cerebellums, and greater numbers of cortex neurons than would be expected given their body size. Smaller brains, smaller cerebellums and fewer cortical neurons potentially allow the beaked whale and pygmy sperm whale to dive longer and deeper than the dolphins. Although more gray matter, more neurons, and a larger cerebellum may limit dolphins to shorter, shallower dives, these features must give them some advantage. For example, they may be able to catch more elusive individual high-calorie prey in the upper ocean.


Assuntos
Cerebelo/anatomia & histologia , Córtex Cerebral/patologia , Mergulho/fisiologia , Golfinhos/fisiologia , Neurônios/patologia , Baleias/fisiologia , Animais , Autopsia/veterinária , Mapeamento Encefálico/veterinária , Contagem de Células , Cerebelo/patologia , Golfinhos/anatomia & histologia , Tamanho do Órgão , Tomografia por Emissão de Pósitrons/veterinária , Fatores de Tempo , Orca/anatomia & histologia , Orca/fisiologia , Baleias/anatomia & histologia
16.
Zootaxa ; 4568(2): zootaxa.4568.2.9, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-31715863

RESUMO

An unfamiliar gastropod was collected from a deep-sea whale carcass at the base of the São Paulo Ridge in the Southwest Atlantic by the manned research submersible Shinkai 6500, and is here described as a new species of the abyssochrysoidean genus Rubyspira, R. brasiliensis sp. nov., following morphological and molecular phylogenetic examinations. There are only two other known species in the genus, which occur together in the Monterey Submarine Canyon off California. The present new species was shown by the molecular analysis to be closer to one of the Californian species than the other. It was found aggregated on and around a whale carcass at a depth of 4204 m, which represents the deepest record of whale- fall ecosystems ever discovered.


Assuntos
Gastrópodes , Baleias , Animais , California , Ecossistema , Filogenia
17.
Dis Aquat Organ ; 137(1): 23-31, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31777396

RESUMO

Southern right whales Eubalaena australis (SRWs) migrate to southern Brazil for breeding and calving from June through November. Overall, there is scarce knowledge on health status and pathologic conditions in SRWs. We report the pathologic and molecular investigation results of 8 SRWs that were necropsied between 2010 and 2017 within a breeding and calving ground in Santa Catarina state, Brazil. The animals were of various ages (7 newborns/calves, 1 adult) and sex (3 females, 5 males). Five whales stranded dead; 3 stranded alive and died shortly after (n = 2) or were euthanized (n = 1). The causes of stranding and/or death were neonatal respiratory distress syndrome with meconium aspiration (n = 3) with concomitant congenital hepatopathy in one of them; trauma of unknown origin (n = 3), infectious renal and lung disease with presumed sepsis (n = 1), and euthanasia (n = 1). Three animals were PCR-positive for cetacean morbillivirus; one of them also had morbilliviral antigen in kidney via immunohistochemical analysis. These results, integrating novel findings and a published report, contribute to the pathology knowledge of this species.


Assuntos
Doenças Transmissíveis , Síndrome de Aspiração de Mecônio , Animais , Brasil , Causas de Morte , Doenças Transmissíveis/veterinária , Feminino , Masculino , Síndrome de Aspiração de Mecônio/veterinária , Baleias
18.
Proc Natl Acad Sci U S A ; 116(42): 21094-21103, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31570615

RESUMO

Distantly related species entering similar biological niches often adapt by evolving similar morphological and physiological characters. How much genomic molecular convergence (particularly of highly constrained coding sequence) contributes to convergent phenotypic evolution, such as echolocation in bats and whales, is a long-standing fundamental question. Like others, we find that convergent amino acid substitutions are not more abundant in echolocating mammals compared to their outgroups. However, we also ask a more informative question about the genomic distribution of convergent substitutions by devising a test to determine which, if any, of more than 4,000 tissue-affecting gene sets is most statistically enriched with convergent substitutions. We find that the gene set most overrepresented (q-value = 2.2e-3) with convergent substitutions in echolocators, affecting 18 genes, regulates development of the cochlear ganglion, a structure with empirically supported relevance to echolocation. Conversely, when comparing to nonecholocating outgroups, no significant gene set enrichment exists. For aquatic and high-altitude mammals, our analysis highlights 15 and 16 genes from the gene sets most affected by molecular convergence which regulate skin and lung physiology, respectively. Importantly, our test requires that the most convergence-enriched set cannot also be enriched for divergent substitutions, such as in the pattern produced by inactivated vision genes in subterranean mammals. Showing a clear role for adaptive protein-coding molecular convergence, we discover nearly 2,600 convergent positions, highlight 77 of them in 3 organs, and provide code to investigate other clades across the tree of life.


Assuntos
Quirópteros/genética , Quirópteros/fisiologia , Ecolocação/fisiologia , Proteínas/genética , Baleias/genética , Baleias/fisiologia , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologia , Substituição de Aminoácidos/genética , Animais , Evolução Molecular , Genoma/genética , Genômica/métodos , Audição/genética , Audição/fisiologia , Filogenia , Seleção Genética/genética
19.
Biol Lett ; 15(10): 20190485, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31594493

RESUMO

Mammals with dependent young often rely on cryptic behaviour to avoid detection by potential predators. In the mysticetes, large baleen whales, young calves are known to be vulnerable to direct predation from both shark and orca predators; therefore, it is possible that mother-calf pairs may show cryptic behaviours to avoid the attention of predators. Baleen whales primarily communicate through low-frequency acoustic signals, which can travel over long ranges. In this study, we explore the potential for acoustic crypsis, a form of cryptic behaviour to avoid predator detection, in North Atlantic right whale mother-calf pairs. We predicted that mother-calf pairs would either show reduced calling rates, reduced call amplitude or a combination of these behavioural modifications when compared with other demographic groups in the same habitat. Our results show that right whale mother-calf pairs have a strong shift in repertoire usage, significantly reducing the number of higher amplitude, long-distance communication signals they produced when compared with juvenile and pregnant whales in the same habitat. These observations show that right whale mother-calf pairs rely upon acoustic crypsis, potentially to minimize the risk of acoustic eavesdropping by predators.


Assuntos
Mães , Baleias , Acústica , Animais , Ecossistema , Feminino , Humanos
20.
BMC Evol Biol ; 19(1): 195, 2019 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-31651234

RESUMO

BACKGROUND: Odontocetes (toothed whales) are the most species-rich marine mammal lineage. The catalyst for their evolutionary success is echolocation - a form of biological sonar that uses high-frequency sound, produced in the forehead and ultimately detected by the cochlea. The ubiquity of echolocation in odontocetes across a wide range of physical and acoustic environments suggests that convergent evolution of cochlear shape is likely to have occurred. To test this, we used SURFACE; a method that fits Ornstein-Uhlenbeck (OU) models with stepwise AIC (Akaike Information Criterion) to identify convergent regimes on the odontocete phylogeny, and then tested whether convergence in these regimes was significantly greater than expected by chance. RESULTS: We identified three convergent regimes: (1) True's (Mesoplodon mirus) and Cuvier's (Ziphius cavirostris) beaked whales; (2) sperm whales (Physeter macrocephalus) and all other beaked whales sampled; and (3) pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales and Dall's porpoise (Phocoenoides dalli). Interestingly the 'river dolphins', a group notorious for their convergent morphologies and riverine ecologies, do not have convergent cochlear shapes. The first two regimes were significantly convergent, with habitat type and dive type significantly correlated with membership of the sperm whale + beaked whale regime. CONCLUSIONS: The extreme acoustic environment of the deep ocean likely constrains cochlear shape, causing the cochlear morphology of sperm and beaked whales to converge. This study adds support for cochlear morphology being used to predict the ecology of extinct cetaceans.


Assuntos
Cóclea/anatomia & histologia , Baleias/anatomia & histologia , Animais , Ecolocação/fisiologia , Filogenia , Análise de Componente Principal
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