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See detailMetals as chemical tracers to discriminate ecological populations of threatened Franciscana dolphins (Pontoporia blainvillei) from Argentina
Romero, M.B.; Polizzi, P.; Chiodi, L. et al

in Environmental Science and Pollution Research (in press)

Franciscana dolphins are the most impacted small cetacean in the Southwestern Atlantic Ocean, classified as Vulnerable A3d by IUCN. Essential (Fe, Mo, Mn, Cr, Ni, Co) and non-essential (Ag, Pb, Sn) trace ... [more ▼]

Franciscana dolphins are the most impacted small cetacean in the Southwestern Atlantic Ocean, classified as Vulnerable A3d by IUCN. Essential (Fe, Mo, Mn, Cr, Ni, Co) and non-essential (Ag, Pb, Sn) trace elements (TEs) were measured in liver, kidney, and brain samples of by-catch Franciscana dolphins that were living in estuarine (n = 21) and marine (n = 21) habitats (1) to assess whether TEs posed a threat and (2) to evaluate the suitability of TEs for discriminating ecological populations of this species in Argentinean waters. Essential TEs showed little variation in tissues from both groups in agreement with levels reported for other cetaceans and suggesting that these concentrations correspond to normal physiological levels. Non-essential TEs were higher in estuarine juveniles and adults dolphins than in marine specimens. These results suggest anthropogenic sources associated with estuarine area and that Franciscana dolphins are good sentinels of the impact of the environment. The difference in the concentrations of TEs beetwen ecological populations appeared to be related to distinct exposures in both geographical areas, and it is suggested that Ag and Sn concentrations in adults are good chemical tracers of anthropogenic input of TEs. These results provide additional information for improved management and regulatory policy. [less ▲]

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See detailLinking pollutant exposure of humpback whales breeding in the Indian Ocean to their feeding habits and feeding areas off Antarctica
Das, Krishna ULg; Malarvannan, Govindan; Dirtu, Alin et al

in Environmental Pollution (2017), 220

Humpback whales, Megaptera novaeangliae, breeding off la Reunion Island (Indian Ocean) undergo large-scale seasonal migrations between summer feeding grounds near Antarctica and their reproductive winter ... [more ▼]

Humpback whales, Megaptera novaeangliae, breeding off la Reunion Island (Indian Ocean) undergo large-scale seasonal migrations between summer feeding grounds near Antarctica and their reproductive winter grounds in the Indian Ocean. The main scope of the current study was to investigate chemical exposure of humpback whales breeding in the Indian Ocean by providing the first published data on this breeding stock concerning persistent organic pollutants (POPs), namely polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), DDT and its metabolites (DDTs), chlordane compounds (CHLs), polybrominated diphenyl ethers (PBDEs), and methoxylated PBDEs (MeO-PBDEs). Analyses of stable isotopes δ13C and δ15N in skin resulted in further insight in their feeding ecology, which was in agreement with a diet focused mainly on low trophic level prey species, such as krill from Antarctica. POPs were measured in all humpback whales in the order of HCB > DDTs > CHLs > HCHs > PCBs > PBDEs > MeO-BDEs. HCB (median: 24 ng.g-1 lw) and DDTs (median: 7.7 ng.g-1 lw) were the predominant compounds in all whale biopsies. Among DDT compounds, p,p’-DDE was the major organohalogenated pollutant, reflecting its long-term accumulation in humpback whales. Significantly lower concentrations of HCB and DDTs were found in females than in males (p<0.001). Other compounds were similar between the two genders (p>0.05). Differences in the HCB and DDTs suggested gender-specific transfer of some compounds to the offspring. POP concentrations were lower than previously reported results for humpback whales sampled near the Antarctic Peninsula, suggesting potential influence of their nutritional status and may indicate different exposures of the whales according to their feeding zones. Further investigations are required to assess exposure of southern humpback whales throughout their feeding zones. [less ▲]

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See detailSpatial variation in the accumulation of POPs and mercury in bottlenose dolphins of the Lower Florida Keys and the coastal Everglades (South Florida)
Damseaux, France ULg; Kiszka, J.; Heithaus, M.R. et al

in Environmental Pollution (2017), 220

The bottlenose dolphin (Tursiops truncatus) is an upper trophic level predator and the most common cetacean species found in nearshore waters of southern Florida, including the Lower Florida Keys (LFK ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an upper trophic level predator and the most common cetacean species found in nearshore waters of southern Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDXs, HCHs, HCB, Σ PCDD/Fs and Σ DL-PCBs) in blubber samples of bottlenose dolphins from LFK (n = 27) and FCE (n = 24). PCBs were the major class of compounds found in bottlenose dolphin blubber and were higher in individuals from LFK (Σ 6 PCBs LFK males: 13421 ± 7730 ng.g-1 lipids, Σ 6 PCBs LFK females: 9683 ± 19007 ng.g-1 lipids) than from FCE (Σ 6 PCBs FCE males: 5638 ng.g-1 ± 3627 lipids, Σ 6 PCBs FCE females: 1427 ± 908 ng.g-1 lipids). These levels were lower than previously published data from the southeastern USA. The Σ DL-PCBs were the most prevalent pollutants of dioxin and dioxin like compounds (Σ DL-PCBs LFK: 739 ng.g-1 lipids, Σ DL-PCBs FCE: 183 ng.g-1 lipids) since PCDD/F concentrations were low for both locations (mean 0.1 ng.g-1 lipids for LFK and FCE dolphins). The toxicity equivalences of PCDD/Fs and DL-PCBs expressed as TEQ in LFK and FCE dolphins is mainly expressed by DL-PCBs (81% LFK - 65% FCE). T-Hg concentrations in skin were significantly higher in FCE (FCE median 9314 ng.g-1 dw) compared to LFK dolphins (LFK median 2941 ng.g-1 dw). These bottlenose dolphins concentrations are the highest recorded in the southeastern USA, and may be explained, at least partially, by the biogeochemistry of the Everglades and mangrove sedimentary habitats that create favourable conditions for the retention of mercury and make it available at high concentrations for aquatic predators. [less ▲]

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See detailPost-embryonic development of sheepshead minnow Cyprinodon variegatus: a staging tool based on externally visible anatomical traits
Schnitzler, Joseph ULg; Dussenne, Mélanie ULg; Frederich, Bruno ULg et al

in Ichthyological Research (2017), 64

The sheepshead minnow Cyprinodon variegatus has become a favoured model for laboratory studies because of their small size, rapid development, and tolerance of laboratory conditions. Here, we analyse ... [more ▼]

The sheepshead minnow Cyprinodon variegatus has become a favoured model for laboratory studies because of their small size, rapid development, and tolerance of laboratory conditions. Here, we analyse sheepshead minnow post-embryonic development with the goal of providing a generally useful method for staging fish after embryogenesis. Groups of three females and two males were placed in breeding chambers designed for this experiment. More than 100 eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope and placed in incubation dishes (50 per dish) at 26 °C. On day six, embryos hatched and larvae were transferred to 1 L beakers. To define a simplified normalization table for sheepshead minnow development, we measured each fish for its standard length and examined the fish for four externally evident traits: pigmentation pattern, caudal fin morphology, anal fin morphology, and dorsal fin morphology. The four traits were chosen, because they are easily visualized with standard laboratory equipment such as the stereomicroscope and camera. We have provided criteria for staging sheepshead minnows in studies of post-embryonic development. Our data suggest that dorsal and anal fin morphology may serve as a useful phenotype for defining metamorphic climax stages throughout post-embryonic development in C. variegatus. The staging systems we propose should facilitate detailed anatomical and developmental analyses in relation to ecotoxicological studies on potential disruption of the thyroid axis by xenobiotics and endocrine-disrupting compounds. [less ▲]

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See detailMorphology of the filtration apparatus of three planktivorous fishes and relation with ingested anthropogenic particles
Collard, France ULg; Gilbert, Bernard ULg; Eppe, Gauthier ULg et al

in Marine Pollution Bulletin (2017)

Anthropogenic particles (APs), including microplastics, are ingested by a wide variety of marine organisms. Exposure of Clupeiformes (e.g. herrings, anchovies, sardines) is poorly studied despite their ... [more ▼]

Anthropogenic particles (APs), including microplastics, are ingested by a wide variety of marine organisms. Exposure of Clupeiformes (e.g. herrings, anchovies, sardines) is poorly studied despite their economic and ecological importance. This study aims to describe the morphology of the filtration apparatus of three wild-caught Clupeiformes (Sardina pilchardus, Clupea harengus and Engraulis encrasicolus) and to relate the results to ingested APs. Consequently, the species with the more efficient filtration apparatus will be more likely to ingest APs. We hypothesized that sardines were the most exposed species. The filtration area and particle retention threshold were determined in the three species, with sardines displaying the highest filtration area and the closest gill rakers. Sardines ingested more fibers and smaller fragments, confirming that it is the most efficient filtering species. These two results lead to the conclusion that, among the three studied, the sardine is the species most exposed to APs. [less ▲]

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See detailExploitation of coastal fish communities by harbour porpoises Phocoena phocoena during nursing periods in German Baltic waters.
Pinzone, Marianna ULg; Michel, Loïc ULg; Gallus, Anja et al

Conference (2016, December 11)

Baltic sub-populations of harbour porpoises Phocoena phocoena meet in in Southwestern waters in Spring when females reach the coastal areas for calving and nursing. In Autumn they separate again for ... [more ▼]

Baltic sub-populations of harbour porpoises Phocoena phocoena meet in in Southwestern waters in Spring when females reach the coastal areas for calving and nursing. In Autumn they separate again for reproduction : the Belt sea populations westwards in the Kattegat/Skarregat region, the Baltic proper population northwards in the central basin. The increased number of juvenile and newborn strandings along the German Baltic coasts give evidence for a possible existence of local calving grounds in this area. Calving and nursing habitats are the most important areas for management purposes. This project aimed to describe inhabitancy and diet of females and calves along the German Baltic coast, in order to achieve effective conservation measures. Nitrogen, carbon and, for the first time, sulphur stable isotopes (δ13C, δ15N and δ34S) were analysed in coastal species of fish and invertebrates in spring, autumn and winter 2015/2016 and in four different areas, to assess for seasonal and geographical variation of porpoises habitat use. The structure of ecological niches was inferred within and between communities using the SIBER model, and was compared to results from stomach content analysis. N, C and S values of fish and invertebrates strongly varied, seasonally and geographically, as a consequence of environmental factors characteristic of each sampling area. Additionally, each species presented large isotopic variability, suggesting possible intraspecific dietary specialisations. Females δ13C and δ34S signatures integrated both open-waters and coastal feeding, while juveniles presented a more coastal distribution. The absence of difference in δ15N values between age classes confirmed persistence of milk assimilation from the mothers. Niches structures and overlaps and stomach content analysis suggested gobies (Potamoschistus spp and Neogobius spp in particular), crabs and small coastal fish (ex. three-spined stickleback) as the main preys of juveniles. The integration of all three stable isotopes together permitted to well delineate even the highly dynamic food web of the Baltic German waters, confirming the use of sulphur isotopes in marine ecological studies. [less ▲]

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See detailTriclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus
Schnitzler, Joseph ULg; Frederich, Bruno ULg; Dussenne, Mélanie ULg et al

in Aquatic Toxicology (2016), 181

Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely ... [more ▼]

Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100 μg L−1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6–13 h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12–15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18–32 h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24–45 h, equivalent to 4–7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions. [less ▲]

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See detailEVALUATION OF FISH EXPOSURE TO POP-LIKE (ORGANOTIN) COMPOUNDS IN SEPETIBA BAY (RIO DE JANEIRO STATE, BRAZIL) THROUGH HEPATIC TOTAL TIN CONCENTRATIONS
Paiva, TC; Schilithz, PF; Bisi, TL et al

in Organohalogen Compounds (2016, August)

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See detailMicroplastics contamination in three planktivorous and commercial fish species
Collard, France ULg; Das, Krishna ULg; Gilbert, Bernard ULg et al

Poster (2016, May)

In 2014, 311 million tonnes of plastics were produced worldwide while it is estimated that 10% ended up in the oceans. Plastics adsorb many pollutants, cause entanglements in many vertebrates and provoke ... [more ▼]

In 2014, 311 million tonnes of plastics were produced worldwide while it is estimated that 10% ended up in the oceans. Plastics adsorb many pollutants, cause entanglements in many vertebrates and provoke blockage of the digestive tract of marine mammals, birds and turtles. Plastics also fragment in smaller parts, forming microplastics (<5 mm). These microplastics have the same size than planktonic organisms and can thus be ingested by filter-feeders and planktivorous organisms including fish. Although planktivorous Clupeiforme species are the most fished species in the world (17 million tonnes in 2013), the possible impact of microplastic ingestion on this group has received little attention. The aim of this study was to quantify and to characterize the ingested anthropogenic particles (AP) in herrings (Clupea harengus), sardines (Sardina pilchardus) and anchovies (Engraulis encrasicolus). Twenty individuals of each species were sampled. Herrings and sardines were caught in the Channel and in the North Sea in January 2013 and in January 2014. Anchovies were sampled in July 2013. The stomach contents were digested by sodium hypochlorite to isolate AP and then they were analysed by Raman spectroscopy and measured. AP were constituted of microplastics (MP) and cellulose fibres, sometimes associated with dyes. We found several plastic families: polyethylene (PE), polypropylene (PP), polystyrene, polyacrylonitrile, polyethylene terephthalate, polyamide and poly(butyl methacrylate). MP occurred in 35%, 50% and 40% of stomach contents of anchovies, sardines and herrings, respectively. Anchovies ingested bigger AP (2 mm) than the two other species. MP was in majority PE followed by PP. Our study shows that highly commercial species are exposed to MP. Further research is needed as MP are transport medium for organic pollutants and their fate once in the organism is unknown. [less ▲]

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See detailContrasted accumulation patterns of persistent organic pollutants and mercury in sympatric tropical dolphins from the south-western Indian Ocean
Dirtu, Alin; Malavannan, Govindan; Das, Krishna ULg et al

in Environmental Research (2016), 146

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the ... [more ▼]

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the contamination with persistent organic pollutants (POPs) and total mercury (T-Hg) of spinner (Stenella longirostris, n=21) and Indo-Pacific bottlenose dolphins (Tursiops aduncus, n=32) sampled from the coastal waters of La Réunion (south-western Indian Ocean). In addition, seven co-occurring teleost fish species were sampled and analyzed as well. Blubber samples from living dolphins and muscle from teleosts were analyzed for polychlorinated biphenyls (PCBs), DDT and metabolites (DDTs), chlordanes (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). Methoxylated PBDEs (MeO-PBDEs), reported as having a natural origin, were also analyzed. T-Hg levels were measured in blubber and skin biopsies of the two living dolphin species. δ13C and δ15N values were determined in skin of the dolphins and in the muscle of teleosts. For PCBs, HCHs and T-Hg, concentrations were significantly higher in T. aduncus than in S. longirostris. For other POP levels, intra-species variability was high. MeO-PBDEs were the dominant compounds (55% of the total POPs) in S. longirostris, while PCBs dominated (50% contribution) in T. aduncus. Other contaminants showed similar profiles between the two species. Given the different patterns of POPs and T-Hg contamination and the stable isotope composition observed among analyzed teleosts, dietary and foraging habitat preferences possibly explain the contrasted contaminant profiles observed in the two dolphin species. Levels of each class of contaminants were significantly higher in males than females. Despite their spatial and temporal overlap in the waters of La Réunion, S. longirostris and T. aduncus are differently exposed to contaminant accumulation. [less ▲]

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See detailDistribution of inorganic and organic contaminants in the intertidal surface sediments along the Hugli River Estuary, eastern part of India
Das, Krishna ULg; Sarkar, Santosh; Thomé, Jean-Pierre ULg et al

Conference (2016, February 17)

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing ... [more ▼]

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing agricultural and aquacultural practices. The present work investigated trace elements (TEs, T-Hg, Al, V, Cr, Fe, Mn, Cu, Zn, Co, Ni, Ca, Sr, Li, Be, P, Mo, Ag, Cd, Sn, Sb, Ba, Pb, Bi, U, As, Se) and organohalogen compounds in surface sediment (top 0-10cm) considering 8 sampling sites along the Hugli River Estuary (HRE), India. The studied organic compounds include polychlorobiphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and metabolites (DDTs) and polybromodiphenyl ethers (PBDEs). Textural analyses of the sediment reveal an overall dominance of mud. All trace elements could be detected at variable concentrations in the following descending order: Al>Fe>Ca> P>Mn> Cu> Zn> Ba >V >Cr>Sr>Ni> Li >Co >Pb>As >Se >U >Be >Sn>Bi >Ag >Mo >Cd >Sb. A synchronous enrichment of majority of the elements were observed at the site Gangasagar (~100 km south megacity Calcutta), situated at the confluence of Hugli River and Bay of Bengal, which might be attributed to cumulative impact of the physicochemical processes and multiple anthropogenic sources. It is revealed that PCBs and DDTs were the dominant compounds among the organic pollutants accounting concentrations up to 23.5 ng.g-1 and 4.4 ng.g-1 respectively at the site Babughat, adjacent to the megacity Calcutta. The results have implications for pollution in complex estuarine environment in a meso-macrotidal setup where there is significant influx of sediments carrying huge load of inorganic and organic pollutants mainly due to rapid urbanization and industrialization. [less ▲]

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See detailMercury and persistent organic pollutant concentrations in free-ranging bottlenose dolphins from Lower Keys and Coastal Everglades (South Florida)
Damseaux, France ULg; Kiszka, Jeremy; Heithaus, Michael et al

Poster (2016, February 12)

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the Florida ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was 1) to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDT, HCH, HCB, DLCs and PCDD/Fs) in blubber samples of bottlenose dolphins from the LFK (8 males and 16 females) and from the FCE (13 males and 9 females). Pollutants were analysed by the mean of Direct Mercury analyser (for T-Hg), GC-ECD (POPs) and GC-MS (DLCs and PCDD/Fs). The PCBs were the main compounds found in bottlenose dolphins from the LFK and FCE. The most present congeners where the CB no. 28, 52, 101, 138, 153 and 180 (ΣPCBs LFK males: 13420.5 ng.g-1 lipids, ΣPCBs LFK females: 9683.4 ng.g-1 lipids, ΣPCBs FCE males: 5637.9 ng.g-1 lipids, ΣPCBs FCE females: 1426.9 ng.g-1 lipids). PCBs concentrations were significantly higher in individuals from the LFK than those from the FCE but significantly lower than those from other locations in the south-eastern US. Unlike organic pollutants, T-Hg concentrations were significantly higher in FCE male dolphins (LFK: 2936.0 ng.g-1 dw, FCE: 10048.3 ng.g-1 dw). These high concentrations were the highest recorded in the south-eastern US and are most likely due to the presence of mangrove ecosystems. This study highlights the complexity of contaminant dynamics (inorganic vs. organic), even at small spatial scales. [less ▲]

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See detailTransfer of contaminants in the food chain up to marine mammals
Das, Krishna ULg

Conference (2016, February)

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See detailEffects of Methylmercury on Harbour Seal Peripheral Blood Leucocytes In Vitro Studied by Electron Microscopy
Dupont, Aurélie; De Pauw-Gillet, Marie-Claire ULg; Schnitzler, Joseph ULg et al

in Archives of Environmental Contamination & Toxicology (2016), 70(1), 133-142

Methylmercury MeHg is highly immunotoxic and can alter the health status of the harbour seal, Phoca vitulina, from the North Sea. To investigate the mechanism of MeHg-induced toxicity in harbour seal ... [more ▼]

Methylmercury MeHg is highly immunotoxic and can alter the health status of the harbour seal, Phoca vitulina, from the North Sea. To investigate the mechanism of MeHg-induced toxicity in harbour seal lymphocytes, ConA-stimulated peripheral blood leucocytes were exposed in vitro to sub-lethal concentrations of MeHgCl (0.2, 1 and 2 µM) for 72h, and then analysed for their viability and ultrastructure. After 72h of incubation, cells were counted with a propidium iodide staining technique, a metabolic MTS assay was performed, and cells exposed to 1 µM MeHgCl were observed by transmission electron microscopy (TEM). Alive cell numbers decreased with increased MeHgCl concentrations. In presence of ConA and 1µM of MeHgCl, TEM images revealed a higher frequency of apoptotic cells. Exposed cells displayed condensation of the chromatin at the nuclear membrane and mitochondrial damages. The results suggest that in vitro MeHgCl induced apoptosis in harbour seal lymphocytes through a mitochondrial pathway. [less ▲]

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See detailXenobiotic and Immune-Relevant Molecular Biomarkers in Harbor Seals as Proxies for Pollutant Burden and Effects?
Lehnert, Kristina; Ronnenberg, Katrin; Weijs, Liesbeth et al

in Archives of Environmental Contamination & Toxicology (2016), 70(1), 106-120

Harbor seals are exposed to increasing pressure caused by anthropogenic activities in their marine environment. Persistent organic pollutants (POPs) and trace elements are hazardous contaminants which ... [more ▼]

Harbor seals are exposed to increasing pressure caused by anthropogenic activities in their marine environment. Persistent organic pollutants (POPs) and trace elements are hazardous contaminants which accumulate in tissues of harbor seals. POPs and trace elements can negatively affect the immune-system and have been reported e.g. to increase susceptibility to viral infections in seals. Biomarkers of the xenobiotic metabolism, cytokines and heat-shock-protein as cell mediators of the immune-system were established to evaluate the impact of environmental stressors on harbor seals. Harbor seals (n=54) were captured on sandbanks in the North Sea during 2009 to 2012. Medicals including hematology were performed, RNAlater blood samples were taken and analyzed using quantitative Polymerase Chain Reaction. Normalized transcript copy numbers were correlated to hematology and POP concentration in blood, and trace metals in blood and fur. [less ▲]

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See detailSeasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability
de la Vega, Camille; Lebreton, Benoit; Siebert, Ursula et al

in PLoS ONE (2016)

The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the ... [more ▼]

The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight. [less ▲]

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See detailGuiana Dolphins (Sotalia guianensis) and DR-CALUX for Screening Coastal Brazilian Environments for Dioxins and Related Compounds
Dorneles, Paulo; Lailson-Brito, Jose; Bisi, Tatiana et al

in Archives of Environmental Contamination & Toxicology (2016)

Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species ... [more ▼]

Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species. However, due to high costs of the analyses, only one investigation comprised the determination of dioxins and related compounds (DRCs) in Guiana dolphin tissues. The dioxin responsive-chemically activated luciferase gene expression (DR-CALUX ) cell bioassay was used in the present study for the analyses of hepatic samples from 28 male Guiana dolphins in order to screen estuarine environments for DRCs, comprising three regions (Northeastern, Southeastern, and Southern) and four states [Parana´ (PR), Rio de Janeiro (RJ), Espı´rito Santo (ES), and Ceara´ (CE)] of Brazil. High bioanalytical equivalent (BEQ) concentrations [dioxins (pg BEQ/g lipid)] were found, varying from 1.94 to 15.6 pg BEQ/g. A significant negative correlation between BEQ concentrations and total length was found in Guiana dolphins from Brazil (all analysed dolphins). This pattern also was verified for RJ state, pointing to (1) chemically induced developmental disruption or to (2) increasing efficiency of the detoxifying activity with the growth of the animal. Comparison was performed with literature data and significantly higher BEQ levels were found in Brazilian Guiana dolphins than in those reported for North Sea harbour porpoises. Higher levels were found in Southeastern (the most PBT-contaminated area of the country) than in Southern region. However, it is not possible to affirm that Guiana dolphins are more contaminated by DRCs in SE than in S region, because individuals were lengthier in S than in SE region. Our results seem to have mirrored dolphin exposure to PCBs in Brazil according to the literature. Further studies are required for investigating the hypotheses 1 and 2 mentioned above. [less ▲]

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See detailThe role of metallothioneins, selenium and transfer to offspring in mercury detoxification in Franciscana dolphins (Pontoporia blainvillei)
Romero, M.B.; Pollizi, P.; Chiodi, L. et al

in Marine Pollution Bulletin (2016)

The concentrations of mercury (Hg), selenium (Se) and metallothioneins (MT) were evaluated in fetuses, calves, juveniles and adults of the endangered coastal Franciscana dolphin (Pontoporia blainvillei ... [more ▼]

The concentrations of mercury (Hg), selenium (Se) and metallothioneins (MT) were evaluated in fetuses, calves, juveniles and adults of the endangered coastal Franciscana dolphin (Pontoporia blainvillei) from Argentina. Mercury concentrations varied among analyzed tissues (liver, kidney, muscle and brain), with liver showing the higher concentrations in all specimens. An age-dependent accumulation was found in liver, kidney and brain. No significant relationship between Hg and MT concentrations was found for all tissues analyzed. Hepatic Hg molar concentrations were positively correlated with those of Se, indicating a great affinity between these two elements. Furthermore, dark granules of HgSe were observed in Kupffer cells in the liver by electron microscopy, suggesting the role of this macrophage in the detoxification of Hg. A transfer of Hg through placenta was proved. The presence of Hg in brain in all age classes did not show concentrations associated with neurotoxicity. [less ▲]

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See detailAbsence of selenium protection against methylmercury toxicity in harbour seal leucocytes in vitro
Das, Krishna ULg; Dupont, Aurélie; De Pauw-Gillet, Marie-Claire ULg et al

in Marine Pollution Bulletin (2016), 108

Previous studies described high concentrations of mercury (Hg) and selenium (Se) in the blood of harbour seals, Phoca vitulina from the North Sea. In the present study, we evaluated the in vitro potential ... [more ▼]

Previous studies described high concentrations of mercury (Hg) and selenium (Se) in the blood of harbour seals, Phoca vitulina from the North Sea. In the present study, we evaluated the in vitro potential protective effects of sodium selenite (Na2SeO3) and selenomethionine (SeMet) on cell proliferation of harbour seal lymphocytes exposed to MeHgCl 0.75 µM. In vitro exposure of ConA-stimulated T lymphocytes resulted in severe inhibition of DNA synthesis, likely linked to severe loss of mitochondrial membrane potential at 0.75 µM. Neither selenite nor SeMet showed a protective effect against MeHg toxicity expressed at the T lymphocyte proliferation level for harbour seals. Selenite and SeMet did not show negative effects regarding lymphocyte proliferation and mitochondrial membrane potential. To conclude, our results clearly demonstrated that MeHg affected in vitro immune cells exposure with no protective effects of selenium at a molar ratio Hg:Se of 1:10 in harbour seals from the North Sea. [less ▲]

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See detailThe thyroid gland and thyroid hormones in sheepshead minnow (Cyprinodon variegatus) during early development and metamorphosis
Schnitzler, Joseph ULg; Klaren, Peter; Mariavelle, Emeline ULg et al

in Fish Physiology and Biochemistry (2016), 42(2), 607-616

The sheepshead minnow is widely used in ecotoxicological studies that only recently have begun to focus on disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However ... [more ▼]

The sheepshead minnow is widely used in ecotoxicological studies that only recently have begun to focus on disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However, reference levels of the thyroid prohormone thyroxine (T4) and biologically active hormone 3,5,30-triiodothyronine (T3) and their developmental patterns are unknown. This study set out to describe the ontogeny and morphology of the thyroid gland in sheepshead minnow, and to correlate these with whole-body concentrations of thyroid hormones during early development and metamorphosis. Eggs were collected by natural spawning in our laboratory. T4 and T3 were extracted from embryos, larvae and juveniles and an enzyme-linked immunoassay was used to measure whole-body hormone levels. Length and body mass, hatching success, gross morphology, thyroid hormone levels and histology were measured. The onset of metamorphosis at 12-day post-hatching coincided with surges in whole-body T4 and T3 concentrations. Thyroid follicles were first observed in pre-metamorphic larvae at hatching and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Follicle size and thyrocyte epithelial cell heights varied during development, indicating fluctuations in thyroid hormone synthesis activity. The increase in the whole-body T3/T4 ratio was indicative of an increase in outer ring deiodination activity. This study establishes a baseline for thyroid hormones in sheepshead minnows, which will be useful for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species. [less ▲]

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