Publications of Thierry Jauniaux
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See detailA meta-analysis of isotopic compositions of North Sea marine mammals
Damseaux, France ULiege; Lepoint, Gilles ULiege; Pomeroy, Paddy et al

Conference (2018, September 18)

For over a decade, the North Sea has been undergoing significant changes due to global changes, global warming and fishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test ... [more ▼]

For over a decade, the North Sea has been undergoing significant changes due to global changes, global warming and fishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test the potential antropogenic impact on feeding behaviour of grey seals, harbour seals and harbour porpoises. Data included δ13C and δ15N values measured in blood cells and muscles from the three species. SIBER, an isotopic niche quantification approach, is used to highlight potential dietary similarity and thus competition between marine mammal species. Harbour seals sampled in Germany showed the highest δ15N values, reflecting a trophic position at the top of the food web, alongside grey seals. In contrast, harbour porpoises sampled from Germany displayed the lowest trophic position. The ellipse overlapping between German harbour and grey seals was very important, showing similarity in, and therefore potential competition for, food sources. On the other hand, the harbour seal and the harbour porpoise of Germany displayed extended ellipse size compared to the grey seal. This may be due to a more diverse diet and, perhaps, a more opportunistic foraging behaviour than grey seals. Surprisingly, another group of grey seals sampled at Isle of May, Scotland displayed lower δ15N values and a very small ellipse size compared to grey seals from Germany, presumably being even more selective in their prey choice. Nevertheless, comparing the trophic position of the groups of grey seals requires caution as the isotopic baseline differed between the two sampling areas. This study allowed the determination of the competition, the spatial variations and the trophic niches of marine mammals in the North Sea and will, at the end, evaluate the effects of the changes in the North Sea on the ecology of marine mammals. [less ▲]

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See detailNew extralimital record of a narwhal (Monodon monoceros) in Europe
Haelters, J.; Kerckhof, F.; Doom, M. et al

in Aquatic Mammals (2018), 44(1), 39-50

On 27 April 2016, a dead narwhal (Monodon monoceros) was found on the bank of the River Scheldt, Belgium. It was the first record of this liigli Arctic cetacean in Belgium, and one of the most southerly ... [more ▼]

On 27 April 2016, a dead narwhal (Monodon monoceros) was found on the bank of the River Scheldt, Belgium. It was the first record of this liigli Arctic cetacean in Belgium, and one of the most southerly records ever in Europe. Due to the decomposition of the carcass, the results of the autopsy remained inconclusive, but it is likely that the animal had died due to a long process of starvation. hi the stomach, a large number of litter items were found which were probably ingested during the process of dying. We further provide information on the sighting of the live animal prior to the stranding and present an overview of the very few known records of narwhal in northwestern Europe. © Aquatic Mammals 2018. [less ▲]

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See detailBeached bachelors: An extensive study on the largest recorded sperm whale Physeter macrocephalus mortality event in the North Sea
IJsseldijk, L. L.; Van Neer, A.; Deaville, R. et al

in PLoS ONE (2018), 13(8),

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 ... [more ▼]

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. © 2018 IJsseldijk et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. [less ▲]

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See detailA meta-analysis of isotopic compositions of North Sea marine mammals
Damseaux, France ULiege; Lepoint, Gilles ULiege; Pomeroy, Paddy et al

Poster (2017, October)

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See detailMulti-approach analysis to assess diet of harbour porpoises Phocoena phocoena in the southern North Sea
Mahfouz, C.; Meziane, T.; Henry, F. et al

in Marine Ecology. Progress Series (2017), 563

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See detailIsotopic compositions of North Sea marine mammals
Damseaux, France ULiege; Pomeroy, Paddy; Sierbert, Ursula et al

Poster (2017)

For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test the potential ... [more ▼]

For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test the potential impact of changes in fish stocks on feeding behaviour of grey seals, harbour seals and harbour porpoises. Data included δ13C and δ15N values measured in blood cells and muscles from the three species. SIBER, an isotopic niche quantification approach, is used to highlight potential dietary similarity and thus competition between marine mammal species. Harbour seals sampled in Germany showed the highest δ15N values, reflecting a trophic position at the top of the food web, alongside grey seals. In contrast, harbour porpoises sampled from Germany displayed the lowest trophic position. The ellipse overlapping between German harbour and grey seals was very important, showing similarity in, and therefore potential competition for, food sources. On the other hand, the harbour seal and the harbour porpoise of Germany displayed extended ellipse size compared to the grey seal. This may be due to a more diverse diet and, perhaps, a more opportunistic foraging behaviour than grey seals. Surprisingly, another group of grey seals sampled at Isle of May, Scotland displayed lower δ15N values and a very small ellipse size compared to grey seals from Germany, presumably being even more selective in their prey choice. Nevertheless, comparing the trophic position of the groups of grey seals requires caution as the isotopic baseline differed between the two sampling areas. This study allowed the determination of the competition, the spatial variations and the trophic niches of marine mammals in the North Sea and will, at the end, evaluate the effects of the changes in the North Sea on the ecology of marine mammals. [less ▲]

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See detailMicroplastics in livers of European anchovies (Engraulis encrasicolus, L.)
Collard, France ULiege; Gilbert, Bernard ULiege; Compère, Philippe ULiege et al

in Environmental Pollution (2017), 229

Microplastics (MPs) are thought to be ingested by a wide range of marine organisms before being excreted. However, several studies in marine organisms from different taxa have shown that MPs and ... [more ▼]

Microplastics (MPs) are thought to be ingested by a wide range of marine organisms before being excreted. However, several studies in marine organisms from different taxa have shown that MPs and nanoplastics could be translocated in other organs. In this study, we investigated the presence of MPs in the livers of commercial zooplanktivorous fishes collected in the field. The study focuses mainly on the European anchovy Engraulis encrasicolus but concerns also the European pilchard Sardina pilchardus and the Atlantic herring Clupea harengus. Two complementary methodologies were used to attest the occurrence of MPs in the hepatic tissue and to exclude contamination. 1) MPs were isolated by degradation of the hepatic tissue. 2) Cryosections were made on the livers and observed in polarized light microscopy. Both methods separately revealed that MPs, mainly polyethylene (PE), were translocated into the livers of the three clupeid species. In anchovy, 80 per cent of livers contained relatively large MPs that ranged from 124 μm to 438 μm, showing a high level of contamination. Two translocation pathways are hypothesized: (i) large particles found in the liver resulted from the agglomeration of smaller pieces, and/or (ii) they simply pass through the intestinal barrier. Further studies are however required to understand the exact process. © 2017 Elsevier Ltd [less ▲]

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See detailCrassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean
Lempereur, Laetitia ULiege; Delobelle, Morgan; Doom, Marjan et al

in Parasitology Open (2017), 3

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See detailMass stranding of ten long-finned pilot whales (Globicephala melas) on the beach of Calais (France)
Jauniaux, Thierry ULiege; Charpentier, JM; André, M et al

Poster (2017)

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See detailProceedings of the 4th FARAH-Day
Bayrou, Calixte ULiege; Cabaraux, Jean-François ULiege; Delguste, Catherine ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l’Université de Liège (2017)

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See detailProceedings of the 3rd FARAH-Day 2016
Bayrou, Calixte ULiege; Cabaraux, Jean-François ULiege; Delguste, Catherine ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l'Université de Liège (2016)

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See detailCauses of death of harbor porpoises (Phocoena phocoena) stranded on the northern French coastline (1995-2015)
Jauniaux, Thierry ULiege; Balin, A.; Bouveroux, T. et al

Conference (2016)

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See detailToxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties
van de Velde, N.; Devleesschauwer, B.; Leopold, M. et al

in Veterinary Parasitology (2016), 230

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See detailProceedings of the 2nd FARAH-Day / Faculty of Veterinary Medicine (University of Liege - Belgium)
Bayrou, Calixte ULiege; Cabaraux, Jean-François ULiege; Delguste, Catherine ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l’Université de Liège (2015)

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See detailEstrogenic Evaluation and Organochlorine Identification in Blubber of North Sea Harbour Porpoise (Phocoena phocoena) Stranded on the North Sea Coast
Didimo Imazaki, Pedro Henrique ULiege; Brose, François ULiege; Jauniaux, Thierry ULiege et al

in BioMed Research International (2015), 2015(Article ID 438295), 13

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using ... [more ▼]

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using a luciferase reporter gene assay (RGA). None of the PCB 138, 153, or 180 or their mixture induced a response in the RGA. o,p'-DDT was the most potent xenoestrogen fromthe DDT group, inducing a response already at 80 ng/mL. From the HCH and HCB group, only 𝛽-HCH (at 400 and 2000 ng/mL) and 𝛿-HCH (at 2000 ng/mL) displayed estrogenic activities.These 13 organochlorines were determined by GC-MS in 12 samples of North Sea harbor porpoise blubber. The PCBs were the main contaminants. Within each group, PCB 153 (6.0 × 102∼4.2 × 104 𝜇g/kg), p,p'- DDE (5.1 × 102∼8.6 × 103 𝜇g/kg), and HCB (7.6 × 101∼1.5 × 103 𝜇g/kg) were the compounds found in highest concentrations.The hormonal activity of the porpoise blubber samples was also assayed in RGA, where two samples showed estrogenic activity, seven samples showed antiestrogenic activity, and one sample showed both estrogenic and antiestrogenic activity. Our results suggest that the 13 POPs measured by GC-MS in the samples cannot explain alone the estrogenicity of the extracts. [less ▲]

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See detailAssessment of the health status of wild fish inhabiting a cotton basin heavily impacted by pesticides in Benin (West Africa).
Agbohessi, Prudencio T.; Imorou Toko, Ibrahim; Ouedraogo, Alfred et al

in The Science of the total environment (2015), 506-507

To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish ... [more ▼]

To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish sampled from rivers located in both contaminated and pristine conditions. Different types of biomarkers, including biometric indices (a condition factor K, a gonadosomatic index GSI, and a hepatosomatic index HSI), plasma levels of sex steroids (11-ketotestosterone 11-KT, testosterone T and estradiol-17beta E2) and the histopathology of the gonads and liver, were investigated for two different trophic levels of the following two fish species: the Guinean tilapia Tilapia guineensis and the African catfish Clarias gariepinus. The fish were captured during both the rainy season (when there is heavy use of pesticides on cotton fields) and the dry season from one site, in Pendjari River (reference site), which is located outside the cotton-producing basin, and from three other sites on the Alibori River within the cotton-producing basin. Comparing fish that were sampled from contaminated (high levels of endosulfan, heptachlor and DDT and metabolites) and reference sites, the results clearly indicated that agricultural pesticides significantly decreased K and GSI while they increased HSI, regardless of the season, species and sex of the fish. These pesticides also induced a decrease in the plasma levels of 11-KT and T and increased those of E2. The histopathology of the testes revealed, in both species, a high rate of testicular oocytes, up to 50% in the African catfish, downstream of the Alibori River, which indicated estrogenic effects from the pesticides. The disruption of male spermatogenesis primarily included necrosis, fibrosis and the presence of foam cells in the lobular lumen. The histopathology of the ovaries revealed high levels of pre-ovulatory follicular atresia, impaired oogenesis, a decrease in the oocyte vitellogenic diameter and other lesions, such as fibrosis, vacuolation and melano-macrophagic centers. The histopathology of the liver revealed the presence of necrosis, hypertrophic hepatocytes, foci of vacuolation, glycogen depletion and hemosiderin. An assessment of the general health of the fish indicated that all of the sampled fish from the polluted sites were in poorer health compared with those from the reference site but that the African catfish appeared much more affected than the Guinean tilapia, regardless of the sex and season. In conclusion, the overall results indicated that agricultural pesticides significantly impair the endocrine regulation of fish living in the Beninese cotton basin and that this would most likely be one of the causes of the severe damage observed in the liver and gonads and the reduced health condition. [less ▲]

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See detailProceedings of the 1st FARAH-Day Faculty of Veterinary Medicine (University of Liege - Belgium)
Bayrou, Calixte ULiege; Cabaraux, Jean-François ULiege; Delguste, Catherine ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l’Université de Liège (2014)

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See detailIn vitro culture of seal muscle-derived satellite cells
Freichels, Astrid ULiege; Baise, Etienne ULiege; Jauniaux, Thierry ULiege et al

Poster (2014, April)

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