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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 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 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 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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See detailPhylogeography of Harbour Porpoise (Phocoena phocoena) in the Eastern North Atlantic and in the Black Sea Explored by the Analyses of Nuclear and Mitochondrial DNA
Fontaine, Michaël; Baird, C.; Stuart, J. E. et al

Poster (2005)

Study of the genetic population structure and the demographic history of the harbour porpoise (Phocoena phocoena) has been nearly comprehensive throughout its distribution in North Atlantic, most studies ... [more ▼]

Study of the genetic population structure and the demographic history of the harbour porpoise (Phocoena phocoena) has been nearly comprehensive throughout its distribution in North Atlantic, most studies using the mitochondrial control region as a genetic marker. Although these studies have shown population structure in some parts of the North Atlantic, mitochondrial DNA is a single, maternally inherited locus and therefore insufficient to fully characterize population structure and history. Polymorphism at 11 microsatellite loci was analyzed in harbour porpoises collected throughout the range of the species in the Central and Eastern North Atlantic from the Iberian peninsula northward to Arctic waters (Portugal, Spain, bay of Biscay, Irish waters, English Channel, the southern bay of the North Sea, Norway, Faroe Islands, and Iceland) and also along the coasts of the Black Sea (Turkey, Ukraine, Bulgaria and Georgia). Multilocus tests for allele frequency differences and population structure estimates indicate complete genetic isolation between Atlantic and Black Sea porpoises. No fine population structure was observed within the Black Sea, and this population displayed a low genetic diversity compared to those of Atlantic. These results can be interpreted in the light of the demographic history of this relict population and the strong founder effect and bottleneck it may have undergone in its past evolution. In Eastern North Atlantic waters, microsatellite data revealed fine scale partitioning of the genetic variation. These results will be compared to the pattern previously reported based on the analysis of the mtDNA control region, and seem to correlate with variation in oceanographic features. [less ▲]

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See detailEcological and pathological factors related to trace metal concentrations in harbour seal Phoca vitulina in the North Sea
Drouguet, Olivier; Siebert, Ursula; Jauniaux, Thierry ULg et al

Poster (2005)

During the last decade, recurrent epizootics have affected harbour seal (Phoca vitulina) populations in the North Sea. Recent data on their trophic habits and pollutant levels are of primary importance ... [more ▼]

During the last decade, recurrent epizootics have affected harbour seal (Phoca vitulina) populations in the North Sea. Recent data on their trophic habits and pollutant levels are of primary importance for their conservation. As isotopic composition of an animal is related to that of its prey, δ13C and δ15N were measured by mass spectrometry in the muscles of 66 harbour seals beached along the coasts of France (n = 10), Belgium (n = 30) and Netherlands (n = 26) between 1994 and 2004. Trace metals concentrations (Zn, Cu, Fe, Cd, Hg and Se) were also determined in liver, kidney and muscles by Inducted Plasma Spectrometry. δ13C and δ15N values remained similar between harbour seals from France (-15.7 0/00; 18.7 0/00, respectively), Belgium (-15.7 0/00; 19.0 0/00, respectively) and Netherlands (-14.7 0/00; 18.7 0/00, respectively). These data are in good agreement with their coastal and piscivorous life style. Isotopic value remained similar between males and females and between body conditions. Hg levels were significantly higher in seals from the southern North Sea when compared to previously published data from seals collected in Norway, probably due some geographical differential exposure. Hepatic Hg was positively correlated to hepatic Se, both increasing with the length of the seals. Such a relationship reflected an age accumulation process coupled to a detoxication mechanism involving antagonism between Hg and Se in the liver. No relationship between stable isotopes and Hg and Cd levels was observed. Increasing Zn and Hg hepatic levels were observed with degrading body condition of the harbour seals, which is reflected by decreasing blubber thickness and high hepatic to total body mass ratio. These observations tend to indicate a global redistribution of trace metals from muscle and blubber to liver, as a result of protein and lipid catabolism linked to disease and starvation. [less ▲]

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See detailA strategy to identify specific biomarkers related to the effects of a PCDD/F mixture on the immune system of marine mammals
Brenez, C.; Gerkens, P.; Mazzucchelli, Gabriel ULg et al

in Talanta (2004), 63(5), 1225-1230

The cell lines chosen have demonstrated a positive response in terms of cell proliferation and associated modifications in proteins content, evaluated through DNA and proteins synthesis, at ... [more ▼]

The cell lines chosen have demonstrated a positive response in terms of cell proliferation and associated modifications in proteins content, evaluated through DNA and proteins synthesis, at environmentally relevant dose of dioxins, brought by a typical environmental PCDD/F mixture. The response is time and species dependent. After completion of the identification of proteins affected by the intoxication, we will identify a set of specific proteins whose expression is correlated to the dioxin dose and submit the cell culture to the treatment with a single chemical as well as with mixtures. We hope that this will allow us to construct and validate a set of protein biomarkers of exposure to pollutants that will show a predictive aspect for unknown chemicals. The quantitative analysis of the set of biomarkers can then be a more specific bioassay and an alternative to physico-chemical or other already established bioanalytical methods for screening purposes. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailSevere fungal pneumonia in harbour porpoises stranded on belgian and french coastline in 2003
Jauniaux, Thierry ULg; Mignon, Bernard ULg; Coignoul, Freddy ULg

in Annual proceedings of the 18th annual conference of the European Cetacean Society (2004)

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See detailIdentification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals
Brenez, Cécile; Gerkens, Pascal; Jauniaux, Thierry ULg et al

Poster (2004)

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See detailEcological and pathological factors related to trace metal concentrations in harbour porpoises Phocoena phocoena from the North Sea and adjacent areas
Das, Krishna ULg; Siebert, Ursula; Fontaine, Michaël ULg et al

in Marine Ecology. Progress Series (2004), 281

There is growing concern about the health status of the harbour porpoise Phocoena phocoena in the North Sea and adjacent areas. The interaction between toxicological results (Zn, Cd, Cu, Fe, Se, Hg ... [more ▼]

There is growing concern about the health status of the harbour porpoise Phocoena phocoena in the North Sea and adjacent areas. The interaction between toxicological results (Zn, Cd, Cu, Fe, Se, Hg), stable isotope data (delta(13)C and delta(15)N) and the most common pathological findings, namely emaciation and lesions of the respiratory system, were investigated in 132 porpoises collected along the coasts of northern France, Belgium, Germany, Denmark, Iceland and Norway between 1994 and 2001. The body condition of harbour porpoises stranded on the French, Belgian and German coasts was poor compared to that of by-catch individuals from Iceland and Norway, as reflected by blubber thickness and hepatic to total body-mass ratio. High Zn and Hg concentrations were observed in some porpoises collected along the southern North Sea coast compared to by-catch individuals from Iceland, Norway and the Baltic Sea. Increasing Zn levels were observed with deteriorating health condition (emaciation and bronchopneumonia), while Hg increases were not significant. The increases were not related to shrinking liver mass which remained unchanged. These observations indicate a general redistribution of trace metals within the organs (muscles and blubber to liver), as a result of protein and lipid catabolism. Muscle delta(13)C and delta(15)N values remained unchanged with deteriorating body condition. Cd concentrations were associated only with age and low delta(15)N values, indicating that high Cd concentrations in Iceland and Norway porpoises may be partly diet-related, i.e. a result of Cd contaminated prey. [less ▲]

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