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1.
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
2.
Chemosphere ; 237: 124448, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31398606

RESUMO

The Mediterranean Sea remains a complex system for mercury (Hg) cycling and accumulation in marine vertebrates. The extremely high levels these animals present demand for an urgent understanding of such processes and the development of new analytical techniques that go beyond the simple contamination monitoring. It was often proposed that prey selection or habitat use may affect Hg contamination in animals; however, it was never possible to measure which factor influences more rates and pathways of contamination. In this paper, we directly integrate toxicological information (Hg levels) and ecological tracers (stable isotopes of C, N and S) into a common data analysis framework (isotopic niches), with the aim of quantifying the influence of species' trophic behaviour on Hg contamination. The analysis was conducted on skin biopsies of fin whales Balaenoptera physalus, long-finned pilot whales Globicephala melas and sperm whales Physeter microcephalus. Their different trophic modes and residency in the area make them model species for the analysis of Hg accumulation along NWMS food webs. We measured Total Hg (T-Hg) concentrations through absorbance spectrometry with the DMA80 Milestone. Carbon, nitrogen and sulphur isotope compositions were measured via mass spectrometry in an IRMS coupled to an Elemental Analyser (EA) Isoprime. Comparison of ecological and contamination niches allowed to explain Hg accumulation in Mediterranean marine predators. Factors such as food web complexity, trophic position, hunting distribution or habitat use (e.g., foraging depth) did not influence Hg exposure. It is rather the selection of prey type, which determines the range of potential Hg sources and as a consequence the rates of accumulation in whales' tissues. A generalist piscivorous species such as the pilot whales will bioaccumulate more Hg than specialised sperm whales feeding mostly on cephalopods.


Assuntos
Ecologia , Monitoramento Ambiental , Cadeia Alimentar , Isótopos/análise , Baleias/metabolismo , Animais , Isótopos de Carbono/análise , Baleia Comum/metabolismo , Mar Mediterrâneo , Isótopos de Mercúrio/análise , Isótopos de Nitrogênio/análise , Cachalote/metabolismo , Isótopos de Enxofre/análise , Poluentes Químicos da Água/análise , Baleias Piloto/metabolismo
3.
Mar Pollut Bull ; 146: 67-75, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426207

RESUMO

Plastic pollution is an omnipresent problem that threatens marine animals through ingestion and entanglement. Marine mammals are no exception to this rule but their interaction with plastic remains understudied in the Mediterranean Sea. Here we highlight this problem by analyzing the stomach contents of 34 individuals from seven odontocete species stranded in Greece. Macroplastic (>5 mm) was found in the stomachs of nine individuals from four species (harbour porpoise Phocoena phocoena, Risso's dolphin Grampus griseus, Cuvier's beaked whale Ziphius cavirostris and sperm whale Physeter macrocephalus) with the highest frequency of occurrence in sperm whales (60%). Gastric blockage from plastic was presumably lethal in three cases, with plastic bags being the most common finding (46%). Plastic ingestion is of particular conservation concern for the endangered Mediterranean sperm whales. A regular examination of stranded cetaceans with a standardised protocol is critical for allowing spatiotemporal comparisons within and across species.


Assuntos
Golfinhos/metabolismo , Phocoena/metabolismo , Plásticos/análise , Cachalote/metabolismo , Baleias/metabolismo , Animais , Caniformia , Grécia , Mar Mediterrâneo , Plásticos/metabolismo , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
4.
Mar Pollut Bull ; 144: 181-188, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31179986

RESUMO

Twelve persistent organic pollutants (POPs) were measured in 11 tissue samples from a pregnant sperm whale stranded on the Huizhou coast of the South China Sea, China, in March 2017. POPs were found to be more concentrated in the irrigated tissues such as placenta, ovary, mammary gland, and liver than the less irrigated tissues such as epidermis. High POP levels detected in the placenta might result in abnormal hormone secretion in the placenta, which would affect the unborn offspring. We hypothesized that ovary is potentially vulnerable to the exposure of higher contaminant levels. The PAH concentrations were higher in the lung than in other tissues, which suggest that PAH levels in the lung were breath-dependent in the sperm whale. The concentrations of POPs except PAHs in the sperm whale blubber were lower than those in the same species in the Northern Hemisphere and were comparable to or lower than those in the same species in the Southern Hemisphere.


Assuntos
Monitoramento Ambiental/métodos , Placenta/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Cachalote/metabolismo , Poluentes Químicos da Água/análise , Tecido Adiposo/química , Animais , China , Feminino , Especificidade de Órgãos , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Gravidez , Distribuição Tecidual , Poluentes Químicos da Água/farmacocinética
5.
Chem Commun (Camb) ; 55(46): 6610-6613, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31119219

RESUMO

The X-ray crystal structure of F43Y/T67R myoglobin revealed unique Tyr-heme double cross-links between Tyr43 and the heme 4-vinyl group, which represents a novel post-translational modification of heme proteins. Moreover, with the feature of a distal His-Arg pair, the designed artificial enzyme exhibited a peroxidase activity comparable to that of native peroxidases, such as the most efficient horseradish peroxidase.


Assuntos
Materiais Biomiméticos/química , Heme/química , Mioglobina/química , Tirosina/química , Animais , Arginina/química , Benzotiazóis/química , Guaiacol/química , Histidina/química , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular , Mutação , Mioglobina/genética , Oxirredução , Peroxidases/química , Processamento de Proteína Pós-Traducional , Cachalote , Ácidos Sulfônicos/química
6.
PLoS One ; 14(2): e0212016, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30811429

RESUMO

The Mediterranean sperm whale population is listed as 'Endangered". The Hellenic Trench is the core habitat of the eastern Mediterranean sperm whale sub-population that numbers two to three hundred individuals. Major shipping routes running on or very close to the 1000 m depth contour along the Hellenic Trench are causing an unsustainable number of ship-strikes with sperm whales reviewed in this paper. Sperm whale sighting and density data were combined with specific information on the vessel traffic in the area (e.g., types of vessels, traffic patterns, speed and traffic density), in order to estimate the risk of a whale/ship interaction. Routing options to significantly reduce ship strike risk by a small offshore shift in shipping routes were identified. The overall collision risk for sperm whales in the study area would be reduced by around 70%, while a maximum of 11 nautical miles would be added to major routes and only around 5 nautical miles for the majority of ships. No negative impacts were associated with re-routing by shipping away from sperm whale habitat and there would be additional shipping safety and environmental benefits. A significant contribution to the overall conservation status of the marine Natura2000 sites in the area and very important population units of threatened species such as Cuvier's beaked whales, monk seals and loggerhead turtles would be achieved, by the reduction of shipping noise and reduced risk of any oil spills reaching the coasts, which are also important touristic destinations in Greece.


Assuntos
Cachalote/fisiologia , Distribuição Animal , Animais , Comércio , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Grécia , Mar Mediterrâneo , Modelos Biológicos , Densidade Demográfica , Navios
7.
Mol Ecol Resour ; 19(4): 944-956, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30735609

RESUMO

Marine mammals are important models for studying convergent evolution and aquatic adaption, and thus reference genomes of marine mammals can provide evolutionary insights. Here, we present the first chromosome-level marine mammal genome assembly based on the data generated by the BGISEQ-500 platform, for a stranded female sperm whale (Physeter macrocephalus). Using this reference genome, we performed chromosome evolution analysis of the sperm whale, including constructing ancestral chromosomes, identifying chromosome rearrangement events and comparing with cattle chromosomes, which provides a resource for exploring marine mammal adaptation and speciation. We detected a high proportion of long interspersed nuclear elements and expanded gene families, and contraction of major histocompatibility complex region genes which were specific to sperm whale. Using comparisons with sheep and cattle, we analysed positively selected genes to identify gene pathways that may be related to adaptation to the marine environment. Further, we identified possible convergent evolution in aquatic mammals by testing for positively selected genes across three orders of marine mammals. In addition, we used publicly available resequencing data to confirm a rapid decline in global population size in the Pliocene to Pleistocene transition. This study sheds light on the chromosome evolution and genetic mechanisms underpinning sperm whale adaptations, providing valuable resources for future comparative genomics.


Assuntos
Organismos Aquáticos/genética , Ecossistema , Evolução Molecular , Genoma , Cachalote/genética , Adaptação Biológica , Animais , Bovinos , Feminino , Ovinos
8.
Sci Total Environ ; 653: 1417-1425, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30759580

RESUMO

Numerous studies to date have reported concentrations of Persistent Organic Pollutants (POPs) in different marine mammal species worldwide. Yet data on sperm whales are scarce from rich and unique biodiverse areas such as the Mediterranean Sea. This work aimed to assess levels of dioxin-like polychlorinated biphenyls (dl-PCBs), polybrominated diphenyl ethers (PBDEs), and polychlorodibenzo-p-dioxins and furans (PCDD/Fs) in blubber of sperm whales stranded along the Italian coast between 2008 and 2016. POP mean concentrations (dl-PCBs: 6410 ng/g l.w.; PBDEs: 612 ng/g l.w.; PCDD/Fs: 57.8 pg/g l.w.) were mostly in line with what has been previously reported on the same species in the Mediterranean environment and tended to be higher than those reported from other geographical regions. The relative abundance followed the order dl-PCBs > PBDEs ≫ PCDD/Fs. Interestingly, the non-ortho dl-PCB pattern (126 > 169 > 77) was similar to that described in other studies worldwide and different from what is described in its main prey. This could be linked to particular metabolic activities in sperm whales against these highly toxic contaminants. Total TEQs ranged from 275 to 987 pg/g l.w. and showed the pattern Σnon-ortho-dl-PCBs > Σortho-dl-PCBs > PCDDs > PCDFs, with PCBs' contribution about 96%. These findings highlight the high abundance of PCBs still found in the Mediterranean environment despite having been banned for decades. All sperm whales analyzed in this study surpassed the threshold of 210 pg WHO-TEQ/g l.w. proposed as starting point of immunosuppression in harbour seals; a level of contamination that may have contributed to an impairment of their immune system.


Assuntos
Monitoramento Ambiental , Éteres Difenil Halogenados/análise , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análise , Cachalote , Poluentes Químicos da Água/análise , Animais , Cadeia Alimentar , Éteres Difenil Halogenados/química , Mar Mediterrâneo , Bifenilos Policlorados/química , Dibenzodioxinas Policloradas/química , Poluentes Químicos da Água/química
9.
Mar Pollut Bull ; 137: 56-60, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30503469

RESUMO

In the French West Indies (Caribbean), the insecticide Chlordecone (CLD) has been extensively used to reduce banana weevil (Cosmopolites sordidus) infestations in banana plantations. Previous studies have shown high CLD concentrations in freshwater and coastal communities of the region. CLD concentrations, however, have not yet been assessed in marine top predators. We investigated CLD concentrations in cetacean blubber tissues from Guadeloupe, including Physeter macrocephalus, Lagenodelphis hosei, Stenella attenuata and Pseudorca crassidens. Chlordecone was detected in all blubber samples analysed, with the exception of four P. macrocephalus. Concentrations (range: 1 to 329 ng·g-1 of lipid weight) were, however, lower than those found in species from fresh and brackish water. Ecological factors (open ocean habitat), CLD kinetics, and cetacean metabolism (high or specific enzymatic activity) might explain low concentrations found in cetacean blubber. Future analyses that include internal organ sampling would help to confirm CLD levels observed in this study.


Assuntos
Cetáceos/metabolismo , Clordecona/análise , Inseticidas/análise , Poluentes Químicos da Água/análise , Tecido Adiposo/química , Tecido Adiposo/metabolismo , Animais , Região do Caribe , Clordecona/metabolismo , Golfinhos/metabolismo , Gorduras/química , Gorduras/metabolismo , Guadalupe , Inseticidas/metabolismo , Musa/crescimento & desenvolvimento , Água do Mar/química , Cachalote/metabolismo , Stenella/metabolismo , Poluentes Químicos da Água/metabolismo , Poluição Química da Água/análise
10.
Inorg Chem ; 57(22): 14269-14279, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30387349

RESUMO

In the L29F variant of myoglobin (Mb), the coordination of oxygen (O2) to the heme Fe atom is stabilized by favorable electrostatic interactions between the polar Fe-O2 moiety and the multipole of the phenyl ring of the Phe29 side chain (Phe29 interaction), in addition to the well-known hydrogen bond (H-bond) between the Fe-bound O2 and the 64th residue (distal H-bond; Carver, T. E.; Brantley, R. E., Jr.; Singleton, E. W.; Arduini, R. M.; Quillin, M. L.; Phillips, G. N., Jr.; Olson, J. S. J. Biol. Chem. 1992, 267, 14443-14450). The O2 and carbon monoxide (CO) binding properties and autoxidation of the L29F/H64L and L29F/H64Q variants reconstituted with a series of chemically modified heme cofactors were analyzed and then compared with those of native Mb, and the L29F, H64Q, and H64L variants similarly reconstituted with the chemically modified heme cofactors in order to elucidate the relationship between the Phe29 interaction and the distal H-bond that critically contributes to stabilization of Fe-bound O2. We found that the Phe29 interaction and distal H-bond act cooperatively to stabilize the Fe-bound O2 in such a manner that the Phe29 interaction strengthens with increasing strength of the distal H-bond. Comparison of the functional properties between the L29F and H64L variants indicated that the synergistic effect of the two interactions decreases the O2 dissociation and autoxidation rate constants of the protein by factors of ∼1/2000 and ∼1/400, respectively. Although the CO binding properties of the proteins were not greatly affected by the distal polar interactions, their synergistic effects were clearly and sharply manifested in the vibrational frequencies of the Fe-bound C-O stretching of the proteins.


Assuntos
Monóxido de Carbono/metabolismo , Ferro/química , Mioglobina/metabolismo , Oxigênio/metabolismo , Animais , Monóxido de Carbono/química , Heme/química , Ligações de Hidrogênio , Cinética , Ligantes , Mutação , Mioglobina/química , Mioglobina/genética , Oxirredução , Oxigênio/química , Ligação Proteica , Cachalote , Eletricidade Estática
11.
Biochemistry ; 57(48): 6649-6652, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30422640

RESUMO

The molecular mechanism of O2 binding to hemoglobin (Hb) and myoglobin (Mb) is a long-standing issue in the field of bioinorganic and biophysical chemistry. The nature of Fe-O2 bond in oxy Hb and Mb had been extensively investigated by resonance Raman spectroscopy, which assigned the Fe-O2 stretching bands at ∼570 cm-1. However, resonance Raman assignment of the vibrational mode had been elusive due to the spectroscopic selection rule and to the limited information available about the ground-state molecular structure. Thus, nuclear resonance vibrational spectroscopy was applied to oxy Mbs reconstituted with 57Fe-labeled native heme cofactor and two chemically modified ones. This advanced spectroscopy in conjunction with DFT analyses gave new insights into the nature of the Fe-O2 bond of oxy heme by revealing the effect of heme peripheral substitutions on the vibrational dynamics of heme Fe atom, where the main Fe-O2 stretching band of the native protein was characterized at ∼420 cm-1.


Assuntos
Mioglobina/química , Animais , Sítios de Ligação , Heme/química , Heme/metabolismo , Ferro/química , Ferro/metabolismo , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Mioglobina/metabolismo , Oxigênio/química , Oxigênio/metabolismo , Conformação Proteica , Análise Espectral Raman , Cachalote , Vibração
12.
J Acoust Soc Am ; 144(1): 365, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30075661

RESUMO

Sperm whales generate multi-pulsed clicks for echolocation and communication with an inter-pulse interval (IPI) determined by the size of their hypertrophied sound producing nose. The IPI has therefore been used to estimate body size and distinguish between individuals, and it has been hypothesized that conspecifics may use IPIs to recognize each other. However, the degree to which IPIs vary within individuals has not explicitly been tested, and therefore the inherent precision of this measure and its applicability for size estimation for researchers and sperm whales alike remain unknown. Here, the variability in IPI from both animal-borne Dtags and far-field recordings from echolocating and communicating sperm whales is quantified. Three different automatic methods (envelope, cepstrum, and cross-correlation) are tested and it is found that the envelope approach results in the least dispersion. Furthermore, it is shown that neither growth, depth, nor recording aspect fully explains the observed variability among clicks recorded from the same individual. It is proposed that dynamics in the soft structures of the nose are affecting IPIs, resulting in a variation of approximately 0.2 ms. Therefore, it is recommended that this variation be considered in IPI studies and that IPIs may have limited functionality as an identity cue among large groups of conspecifics.


Assuntos
Tamanho Corporal/fisiologia , Ecolocação/fisiologia , Frequência Cardíaca/fisiologia , Vocalização Animal/fisiologia , Acústica , Animais , Espectrografia do Som/métodos , Cachalote , Fatores de Tempo
13.
PLoS One ; 13(8): e0201221, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30086178

RESUMO

Between the 8th January and the 25th February 2016, the largest sperm whale Physeter macrocephalus mortality event ever recorded in the North Sea occurred with 30 sperm whales stranding in five countries within six weeks. All sperm whales were immature males. Groups were stratified by size, with the smaller animals stranding in the Netherlands, and the largest in England. The majority (n = 27) of the stranded animals were necropsied and/or sampled, allowing for an international and comprehensive investigation into this mortality event. The animals were in fair to good nutritional condition and, aside from the pathologies caused by stranding, did not exhibit significant evidence of disease or trauma. Infectious agents were found, including various parasite species, several bacterial and fungal pathogens and a novel alphaherpesvirus. In nine of the sperm whales a variety of marine litter was found. However, none of these findings were considered to have been the primary cause of the stranding event. Potential anthropogenic and environmental factors that may have caused the sperm whales to enter the North Sea were assessed. Once sperm whales enter the North Sea and head south, the water becomes progressively shallower (<40 m), making this region a global hotspot for sperm whale strandings. We conclude that the reasons for sperm whales to enter the southern North Sea are the result of complex interactions of extrinsic environmental factors. As such, these large mortality events seldom have a single ultimate cause and it is only through multidisciplinary, collaborative approaches that potentially multifactorial large-scale stranding events can be effectively investigated.


Assuntos
Cachalote , Migração Animal , Animais , Autopsia/veterinária , Dieta/veterinária , Inglaterra , Monitoramento Ambiental , Masculino , Mortalidade , Países Baixos , Mar do Norte , Cachalote/microbiologia , Cachalote/parasitologia , Cachalote/fisiologia
14.
Vet Rec ; 183(7): 208-209, 2018 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-30120176

RESUMO

In 2016, 30 sperm whales died having stranded in the southern North Sea. Researchers have now investigated what caused this. Georgina Mills reports.


Assuntos
Mortalidade , Cachalote , Animais , Masculino , Mar do Norte/epidemiologia
15.
J Phys Chem B ; 122(49): 11228-11239, 2018 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-30133301

RESUMO

Under mildly acidic conditions (pH 4-4.5) apomyoglobin (apoMb) adopts a partially structured equilibrium state ( M-state) that structurally resembles a kinetic intermediate encountered at a late stage of folding to the native structure at neutral pH. We have previously reported that the M-state is formed rapidly (<1 ms) via a multistate process and thus offers a unique opportunity for exploring early stages of folding by both experimental and computational techniques. In order to gain structural insight into intermediates and barriers at the residue level, we studied the folding/unfolding kinetics of 12 apoMb mutants at pH 4.2 using fluorescence-detected ultrafast mixing techniques. Global analysis of the submillisecond folding/unfolding kinetics vs urea concentration for each variant, based on a sequential four-state mechanism ( U ⇔ I ⇔ L ⇔ M), allowed us to determine elementary rate constants and their dependence on urea concentration for most transitions. Comparison of the free energy diagrams constructed from the kinetic data of the mutants with that of wild-type apoMb yielded quantitative information on the effects of mutations on the free energy (ΔΔ G) of both intermediates and the first two kinetic barriers encountered during folding. Truncation of conserved aliphatic side chains on helices A, G, and H gives rise to a stepwise increase in ΔΔ G as the protein advances from U toward M, consistent with progressive stabilization of native-like contacts within the primary core of apoMb. Helix-helix contacts in the primary core contribute little to the first folding barrier ( U ⇔ I) and thus are not required for folding initiation but are critical for the stability of the late intermediate, L, and the M-state. Alanine substitution of hydrophobic residues at more peripheral helix-helix contact sites of the native structure, which are still absent or unstable in the M-state, shows both positive (destabilizing) and negative (stabilizing) ΔΔ G, indicating that non-native contacts are formed initially and weakened or lost as a result of subsequent structural rearrangement steps.


Assuntos
Apoproteínas/química , Mioglobina/química , Animais , Apoproteínas/genética , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Mutagênese Sítio-Dirigida , Mutação , Mioglobina/genética , Conformação Proteica em alfa-Hélice , Desdobramento de Proteína , Cachalote , Termodinâmica
16.
Sci Rep ; 8(1): 11577, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30068967

RESUMO

Mass strandings of sperm whales (Physeter macrocephalus) are rare in the Mediterranean Sea. Nevertheless, in 2014 a pod of 7 specimens stranded alive along the Italian coast of the Central Adriatic Sea: 3 individuals died on the beach after a few hours due to internal damages induced by prolonged recumbency; the remaining 4 whales were refloated after great efforts. All the dead animals were genetically related females; one was pregnant. All the animals were infected by dolphin morbillivirus (DMV) and the pregnant whale was also affected by a severe nephropathy due to a large kidney stone. Other analyses ruled out other possible relevant factors related to weather conditions or human activities. The results of multidisciplinary post-mortem analyses revealed that the 7 sperm whales entered the Adriatic Sea encountering adverse weather conditions and then kept heading northward following the pregnant but sick leader of the pod, thereby reaching the stranding site. DMV infection most likely played a crucial role in impairing the health condition and orientation abilities of the whales. They did not steer back towards deeper waters, but eventually stranded along the Central Adriatic Sea coastline, a real trap for sperm whales.


Assuntos
Comportamento Animal , Infecções por Morbillivirus/veterinária , Morbillivirus/isolamento & purificação , Cachalote , Animais , Itália , Mar Mediterrâneo , Infecções por Morbillivirus/patologia
17.
Sci Rep ; 8(1): 10958, 2018 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30026609

RESUMO

Ecological and physiological factors lead to different contamination patterns in individual marine mammals. The objective of the present study was to assess whether variations in contamination profiles are indicative of social structures of young male sperm whales as they might reflect a variation in feeding preferences and/or in utilized feeding grounds. We used a total of 61 variables associated with organic compounds and trace element concentrations measured in muscle, liver, kidney and blubber gained from 24 sperm whales that stranded in the North Sea in January and February 2016. Combining contaminant and genetic data, there is evidence for at least two cohorts with different origin among these stranded sperm whales; one from the Canary Island region and one from the northern part of the Atlantic. While genetic data unravel relatedness and kinship, contamination data integrate over areas, where animals occured during their lifetime. Especially in long-lived animals with a large migratory potential, as sperm whales, contamination data may carry highly relevant information about aggregation through time and space.


Assuntos
DNA Mitocondrial/genética , Cachalote/classificação , Oligoelementos/análise , Poluentes Químicos da Água/análise , Animais , Comportamento Animal , Monitoramento Ambiental , Haplótipos , Rim/química , Fígado/química , Masculino , Músculos/química , Mar do Norte , Comportamento Social , Cachalote/genética , Cachalote/fisiologia
18.
PLoS One ; 13(7): e0200260, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29985953

RESUMO

Recent studies have identified that the myodural bridge (MDB) is located between the suboccipital muscles and cervical dura mater in the posterior atlanto-occipital interspace within humans. The myodural bridge has been considered to have a significant role in physiological functions. However, there is little information about the myodural bridge in marine mammals; we conducted this study to investigate and examine the morphology of the myodural bridge in a sperm whale. We also aim to discuss the physiological functions of the myodural bridge. In this study, a 15.1-meter long sperm whale carcass was examined. Multiple methods were conducted to examine the bridges of the sperm whale which included dissection, P45 plastination and histological analysis. This study confirmed the existence of the myodural bridge in the sperm whale and shows there are two types of the bridge in the sperm whale: one type was the occipital-dural bridge (ODB), the other type was the MDB. A large venous plexus was found within the epidural space and this venous plexus is thought to contain a great amount of blood when in deep water and thus the movements of suboccipital muscles could be a unique power source that drives cerebrospinal fluid circulation.


Assuntos
Vértebras Cervicais/anatomia & histologia , Dura-Máter/anatomia & histologia , Músculos do Pescoço/anatomia & histologia , Pescoço/anatomia & histologia , Cachalote/anatomia & histologia , Animais , Dissecação
19.
Sci Rep ; 8(1): 11163, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-30042515

RESUMO

Benthic community succession patterns at whale falls have been previously established by means of punctual submersible and ROV observations. The contribution of faunal activity rhythms in response to internal tides and photoperiod cues to that community succession dynamism has never been evaluated. Here, we present results from a high-frequency monitoring experiment of an implanted sperm whale carcass in the continental slope (500 m depth) offshore Sagami Bay, Japan. The benthic community succession was monitored at a high frequency in a prolonged fashion (i.e. 2-h intervals for 2.5 months) with a seafloor lander equipped with a time-lapse video camera and an acoustic Doppler profiler to concomitantly study current flow dynamics. We reported here for the first time, to the best of our knowledge, the occurrence of strong 24-h day-night driven behavioral rhythms of the most abundant species (Simenchelys parasitica; Macrocheira kaempferi, and Pterothrissus gissu). Those rhythms were detected in detriment of tidally-controlled ones. Evidence of a diel temporal niche portioning between scavengers and predators avoiding co-occurrence at the carcass, is also provided. The high-frequency photographic and oceanographic data acquisition also helped to precisely discriminate the transition timing between the successional stages previously described for whale falls' attendant communities.


Assuntos
Restos Mortais , Monitorização de Parâmetros Ecológicos/métodos , Cadeia Alimentar , Periodicidade , Cachalote , Ondas de Maré , Acústica/instrumentação , Análise de Variância , Animais , Baías , Peso Corporal , Braquiúros/fisiologia , Enguias/fisiologia , Japão , Masculino , Análise Multivariada , Comportamento Predatório , Tubarões/fisiologia , Gravação em Vídeo
20.
J Theor Biol ; 455: 109-117, 2018 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-30017945

RESUMO

We develop a two-state Markov chain to describe the effect of reoccurring disturbances on a population that is modeled by discrete-time matrix model. The environment is described by three parameters that define the magnitude of impact of a disturbance, the average duration of impact of a disturbance, and the average time between disturbances. We derive an approximation for the stochastic growth rate in order to examine how these three parameters affect population growth. From this approximation, we calculate the sensitivity and elasticity of the growth rate with respect to the environmental parameters. We show that the average duration of impact of a disturbance and the average time between disturbances contribute equally to the stochastic growth rate. We also show that the elasticity of the stochastic growth rate is more sensitive to changes in the magnitude of impact than to changes in either the average duration of impact of a disturbance or the average time between disturbances. These conclusions hold irrespective of the population under consideration. We then provide an application of the model formulation to examine how disturbances, such as oil spills, may affect a sperm whale population. The model results suggest that, in oder to mitigate the impact of disturbances, management strategies should focus on reducing the magnitude of impact. Meanwhile, if it is more feasible to reduce either the duration of impact or the time between impacts, managers should focus on whichever is easier to obtain. In addition, when applied to a sperm whale population, our model shows that the probability of extinction can dramatically increase when disturbance frequency increases but is not greatly impacted by the assumption that all disturbances have the same magnitude.


Assuntos
Organismos Aquáticos/fisiologia , Modelos Biológicos , Cachalote/fisiologia , Animais , Feminino , Masculino , Cadeias de Markov , Dinâmica Populacional , Processos Estocásticos
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