References of "Jauniaux, Thierry"
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See detailHarbour porpoises stranded on the Dutch coast in 2007: Impact of by cath and related lesions
Grondin, Alexia; Camphuysen, K.; Ghisbain, T. et al

Poster (2008)

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See detailCauses of death of harbor porpoises (Phocoena phocoena) stranded on the Dutch coast
Jauniaux, Thierry ULg; Bergerie, H.; Camphuysen, K. et al

in proceeding of the annual conference (2008)

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See detailRehabilitation of oiled marine mammals: an assessment
Jauniaux, Thierry ULg

in Meeting report (2008)

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See detailRise of oceanographic barriers in continuous populations of a cetacean: the genetic structure of harbour porpoises in Old World waters
Fontaine, Michaël C. ULg; Baird, Stuart J. E.; Piry, Sylvain et al

in BMC Biology (2007), 5

BACKGROUND: Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally ... [more ▼]

BACKGROUND: Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally little evidence of what could effectively restrict their dispersal. In the present work, we applied a combination of recent individual-based landscape genetic approaches to investigate the population genetic structure of a highly mobile extensive range cetacean, the harbour porpoise in the eastern North Atlantic, with regards to oceanographic characteristics that could constrain its dispersal. RESULTS: Analyses of 10 microsatellite loci for 752 individuals revealed that most of the sampled range in the eastern North Atlantic behaves as a 'continuous' population that widely extends over thousands of kilometres with significant isolation by distance (IBD). However, strong barriers to gene flow were detected in the south-eastern part of the range. These barriers coincided with profound changes in environmental characteristics and isolated, on a relatively small scale, porpoises from Iberian waters and on a larger scale porpoises from the Black Sea. CONCLUSION: The presence of these barriers to gene flow that coincide with profound changes in oceanographic features, together with the spatial variation in IBD strength, provide for the first time strong evidence that physical processes have a major impact on the demographic and genetic structure of a cetacean. This genetic pattern further suggests habitat-related fragmentation of the porpoise range that is likely to intensify with predicted surface ocean warming. [less ▲]

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See detailVIABILITY OF THE NORTHEAST ATLANTIC HARBOUR PORPOISE AND SEAL POPULATION (GENETIC AND ECOLOGICAL STUDY)
Das, Krishna ULg; Drouguet, Olivier; Fontaine, Michaël ULg et al

Report (2007)

Harbour porpoises (Phocoena phocoena) and harbour seals (Phoca vitulina) are far more abundant along our coast compared to the beginning of the nineties. Human impact on these species is however hard to ... [more ▼]

Harbour porpoises (Phocoena phocoena) and harbour seals (Phoca vitulina) are far more abundant along our coast compared to the beginning of the nineties. Human impact on these species is however hard to establish, mainly due to lack of information on marine mammal population ecology, density, distribution and diversity. This project aims to gain further knowledge on the viability of the harbour porpoise and harbour seal populations in the North Sea (focusing mainly on its southern Bight) through - The characterisation of their genetic structure and diversity (through mtDNA and microsatellites in harbour porpoises) - A better understanding of their feeding ecology (through δ13C and δ15N measurements in muscles) - The assessment of their susceptibility of being trapped accidentally in fishing nets (post-mortem investigations) Harbour porpoise and harbour seal occupied the top trophic levels but displayed different feeding habits as inferred from their δ13C and δ15N mean values. Harbour porpoises displayed lower mean δ15N values suggesting a lower trophic position likely oriented towards small planktivorous fish such as herring and lesser sandeel. However, both their recent high abundance and their dietary preferences might lead to a higher susceptibility to by-catch as revealed by the significant emergence of net entrapment and net marks revealed by post-mortem investigations. The question rises about the sustainability of these incidental captures. Furthermore, genetic investigations revealed a higher fragmentation of the porpoises collected along the coast of France, Belgium and Netherlands. This apparent fragmentation is of particular importance from a conservation point of view and enhances the fact to protect in priority these last populations. Our study showed importance of multidisciplinary approaches (post-mortem investigations, stable isotope measurements (δ13C and δ15N measurements) and genetic investigations using mtDNA and microsatellites) to apprehend the question of marine mammal survival in our waters. [less ▲]

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See detailFatty acids and stable isotopes in fish and harbour porpoises (Phocoena phocoena) from the North Sea: further insights in their trophic relationships
Drouguet, Olivier; Caut, Stéphane; Haelters, Jan et al

Poster (2007)

Recent observations revealed an increased abundance of the harbour porpoise in the southern part of the North Sea. Concomitant to sightings of living individuals, the number of stranded porpoises ... [more ▼]

Recent observations revealed an increased abundance of the harbour porpoise in the southern part of the North Sea. Concomitant to sightings of living individuals, the number of stranded porpoises displaying lesions linked to fishing nets has also increased this last decade. The increased abundance of porpoises together with the increase in numbers of bycaught animals raised the question of possible competition between porpoises and fishermen in the North Sea. Therefore, a detailed view on harbour porpoise trophic ecology in this region is crucial for their conservation. Stomachs of the washed ashore porpoises were often empty and provided limited information on their recent diet. Another way of looking into the diet of marine mammals is the analysis of blubber. Stable isotopes ratio (d13C and d15N, SI) and fatty acid composition (20 fatty acids, FA) were analyzed in muscle and blubber of 10 freshly stranded harbour porpoises and in 60 potential prey fish from 10 species collected in the North Sea. The SI ratio and FA composition of these fish enabled a clear classification in different trophic levels and different trophic niches. The FA composition was very similar between harbour porpoise blubber and demersal fish, underlining a preferential predation on that resource for the porpoises investigated. A bias might exist for the porpoises: most of the animals were juveniles, and washed ashore during spring. Porpoises might display other feeding habits in other life stages, other periods of the year. These preliminary results however indicate the enhanced accuracy of crossing these biomarker approaches. [less ▲]

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See detailLesions observed on harbor porpoises (Phocoena phocoena) stranded on the Dutch coast in 2006
Jauniaux, Thierry ULg; Bergerie, H.; Camphuysen, K. et al

(2007)

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See detailStranding of a humpback whale (Megaptera novaeangliae) on the Belgian coast
Jauniaux, Thierry ULg; Brenez, C.; Haelters, J. et al

in proceeding of the annual conference (2006)

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See detailEvolution des échouages et des causes de mortalité des mammifères marins dans le nord de la France (1995-2005)
Jauniaux, Thierry ULg; Brenez, C.; Haelters, J. et al

in annual proceeding (2006)

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See detailZn, Cu, Cd and Hg Binding to Metallothioneins in Harbour Porpoises Phocoena Phocoena from the Southern North Sea
Das, Krishna ULg; De Groof, Arnaud; Jauniaux, Thierry ULg et al

in BMC Ecology (2006), 6

BACKGROUND: Harbour porpoises Phocoena phocoena from the southern North Sea are known to display high levels of Zn and Hg in their tissues linked to their nutritional status (emaciation). The question ... [more ▼]

BACKGROUND: Harbour porpoises Phocoena phocoena from the southern North Sea are known to display high levels of Zn and Hg in their tissues linked to their nutritional status (emaciation). The question arises regarding a potential role of metallothioneins (MTs) with regard to these high metal levels. In the present study, metallothionein detection and associated Zn, Cd, Cu and Hg concentrations were investigated in the liver and kidney of 14 harbour porpoises collected along the Belgian coast. RESULTS: Metallothioneins seemed to play a key role in essential metal homeostasis, as they were shown to bind 50% of the total hepatic Zn and 36% of the total hepatic Cu concentrations. Renal MTs also participated in Cd detoxification, as they were shown to bind 56% of the total renal Cd. Hg was mainly found in the insoluble fraction of both liver and kidney. Concomitant increases in total Zn concentration and Zn bound to MTs were observed in the liver, whereas Zn concentration bound to high molecular weight proteins remained constant. Cu, Zn and Cd were accumulated preferentially in the MT fraction and their content in this fraction increased with the amount in the hepatocytosol. CONCLUSION: MTs have a key role in Zn and Cu homeostasis in harbour porpoises. We demonstrated that increasing hepatic Zn concentration led to an increase in Zn linked to MTs, suggesting that these small proteins take over the Zn overload linked to the poor body condition of debilitated harbour porpoises. [less ▲]

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See detailInterfollicular fibrosis and organohalogens in the thyroid of the harbour porpoise (phocoena phocoena) of the British and Belgian coasts
Schnitzler, Joseph ULg; Das, Krishna ULg; Beineke, Andreas et al

Conference (2005, October 27)

Previous studies have described high levels of polychlorobiphenyls (PCB), p,p`-dichlordiphenyl-dichlorethen (DDT), p,p`-dichlordiphenyl-trichlorethan (DDE) and polybrominated diphenylether (PBDE) in the ... [more ▼]

Previous studies have described high levels of polychlorobiphenyls (PCB), p,p`-dichlordiphenyl-dichlorethen (DDT), p,p`-dichlordiphenyl-trichlorethan (DDE) and polybrominated diphenylether (PBDE) in the blubber of the harbour porpoise (Phocoena phocoena) from the North Sea raising the question of a potential endocrine disruption in this species. In the present study, the thyroids of 36 harbour porpoises from the British and the Belgian coast have been collected for histological and immunohistological investigations. The number and mean diameter of follicles and the relative distribution of follicular, connective and vascular tissues (%) were quantified in the thyroid of each individual. Then, the relationship between the thyroid morphometry data and previously described organic compounds (namely PCB, DDT, DDE and PBDE) was investigated using factor analysis and multiple regressions. The results of this work were compared to the previous study of harbour porpoises from the German (North and Baltic Seas), Norwegian and Icelandic coasts. Thyroid morphology was similar between the harbour porpoises from the British and Belgian coast. Compared to the previous study, the thyroids differed strongly between sampling sites. Porpoises from the German (North and Baltic Seas) and Norwegian coasts displayed a high percentage of connective tissues between 30 and 38% revealing severe inter-follicular fibrosis. The thyroids of Icelandic coasts displayed only a light inter-follicular fibrosis (percentage of connective tissue of 3%). The thyroids of the porpoises from the British and Belgian coasts occupied an intermediary place with a moderate fibrosis (percentage of connective tissue of 10%). A relation between mean diameter of follicles and the body size and mass suggesting a downward trend of activity of the thyroid with increasing body size and mass and thus, the age of the porpoises. A correlation-based principal component analysis (PCA) revealed one principal components explaining 69% of the total variance. The variables PCB, PBDE, DDT, and DDE compounds loaded highest on PC1. Our results pointed out a relationship between PCBs, PBDE, DDE and DDT (PC1) compounds and interfollicular fibrosis in the thyroids of harbour porpoises from the German coast of the Baltic Sea. The present report supports the hypothesis of a contaminant-induced thyroid fibrosis in harbour porpoises raising the question of the long term-viability in highly polluted areas [less ▲]

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See detailBelgium stranding network
Jauniaux, Thierry ULg; Das, Krishna ULg; Brenez, C. et al

in annual proceeding (2005)

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See detailPlongée et barotraumatisme chez les cétacés
Jauniaux, Thierry ULg

in annual proceeding (2005)

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