News Article | May 2, 2017
One of the highest concentrations of toxic pollutants ever recorded in a marine mammal has been revealed in a Scottish killer whale that died in 2016. The adult whale, known as Lulu, was a member of the UK’s last resident pod and a postmortem also showed she had never produced a calf. The pollutants, called PCBs, are known to cause infertility and these latest findings add to strong evidence that the pod is doomed to extinction. The level of PCBs found in Lulu’s blubber were extreme at 950mg/kg, more than 100 times the 9mg/kg limit above which damage to the health of marine mammals is known to occur. A 2016 analysis showed the average concentration for killer whales in the north-east Atlantic was about 150mg/kg. Lulu died after becoming tangled in ropes used to haul up creels, the netted cages used to catch lobsters and crabs. But Andrew Brownlow, head of the Scottish Marine Animal Stranding Scheme, said: “Given what is known about the toxic effects of PCBs, we have to consider that such a high-pollutant burden could have been affecting her health and reproductive fitness.” Brownlow, also a veterinary pathologist at Scotland’s Rural College, said: “Lulu’s apparent infertility is an ominous finding – with no new animals being born, it is now looking increasingly likely that this small group will eventually go extinct. One of the factors in this groups apparent failure to reproduce could be their high burden of organic pollutants.” The examination of Lulu found she was at least 20 years old, well above the age of sexual maturity, which ranges from six to 10 years old. However, analysis of the ovaries shows she never bore a calf. The entire pod may have been left barren, as no calf has ever been seen in the 23 years the group have been monitored. PCBs were used for decades in electrical equipment but finally banned in the 1980s after the full toxic impacts on people and wildlife were revealed. PCBs, which cause cancers and suppress the immune system, are especially harmful to top predators because they accumulate in fat up the food chain. Killer whales can live for many decades, meaning they can end up with very high levels of PCBs. PCBs are extremely tough chemicals and do not break down in the environment. The decline in PCB levels in marine wildlife seen after the 1980s ban has now levelled off in some places, indicating that the toxic chemicals are still leaking into the oceans from inadequate waste storage sites. “Once PCBs get into the marine environment, they are difficult if not impossible to remove,” said Brownlow. “There are still many PCB stockpiles in Europe, and it is absolutely essential that these toxic reserves do not reach the marine environment.” Bottlenose dolphins in the north-east Atlantic have also shown both high PCB levels and low reproductive rates. Other PCBs hotspots around the world include the entire Mediterranean and the Black Sea, while specific populations suffering from PCB poisoning include belugas in Canada and polar bears across the Arctic. In February, scientists discovered “extraordinary” amounts of PCBs had even reached the most remote and inaccessible place on the planet – the 10km deep Mariana trench in the Pacific Ocean.
News Article | May 5, 2017
A member of a small group of killer whales was found dead early last year on the Isle of Tiree in Scotland. Over a year on, analysis shows that the creature's toxicity level was exceedingly higher than the accepted level for most marine mammals. It was January of 2016 when a killer whale was found dead and stranded on the Isle of Tiree in Hebrides, Scotland. The dead adult killer whale was later identified as Lulu, a member of a group of killer whales on the west coast of the country. Back then, Lulu's cause of death was identified as due to entanglement with a creel rope, but recent evidence shows that there could be another factor that would have killed Lulu even if she had not gotten entangled in the ropes, or perhaps may have led her to live a less than healthy life. Analysis of Lulu's blubber shows that the killer whale had a polychlorinated biphenyl (PCB) toxicity level that is 80 times higher than that of the acceptable toxicity level for marine mammals. This means that Lulu's health was likely compromised due to the toxic contamination in her body. High PCB levels among marine mammals are linked to poor health, increased susceptibility to cancers, a poor immune system, and infertility; some things that Lulu seems to have suffered. Based on the analysis of Lulu's ovaries, though she was at least 20 years old at the time of her death, an age that is much older than the average age of maturity for the species, Lulu was not able to reproduce in her lifespan. What worries experts even more is that the group of killer whales which Lulu belonged to was a small group of whales who do not interact with other groups of killer whales, and has not been seen with a calf in their 23 years of observation. "Lulu's apparent infertility is an ominous finding for the long-term survivability of this group; with no new animals being born, it is now looking increasingly likely that this small group will eventually go extinct," said Dr. Andrew Brownlow from the Scottish Marine Animal Stranding Scheme and veterinary pathologist at Scotland's Rural College. The case of Lulu's death runs similar to a study that was published early this year about how persistent organic pollutants (POPs) are threatening the existence of polar bears. Though POPs have been banned in the 1980s, as the name suggests, its persistence remains to be a problem among humans as well as marine mammals as its effects can be felt even years after production has been halted. In Lulu's case, the PCB toxicity level found in a sample of her blubber exceeded 950 parts per million (ppm), which is the highest ever recorded in a marine mammal. The findings about Lulu provide further evidence about the adverse effects of POPs and PCBs on marine mammals, and it also shows that certain human acts have a lasting effect on marine creatures, even long after the act itself has been stopped. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Davison N.J.,Animal Health and Veterinary Laboratories Agency |
Barnett J.E.F.,Animal Health and Veterinary Laboratories Agency |
Dawson C.E.,Scottish Marine Animal Stranding Scheme |
Perkins M.W.,UK Institute of Zoology |
And 2 more authors.
Journal of Wildlife Diseases | Year: 2013
Brucella species infection in marine mammal species has been reported to have a global distribution. In 2007, the description of Brucella ceti was published and formally adopted for those isolates originating from cetaceans and pathologic lesions similar to those seen in terrestrial mammals infected with Brucella spp. have been associated with its isolation. Brucella ceti infection specific to the central nervous system has been described in two species of cetacean: striped dolphins (Stenella coeruleoalba) in Europe and Costa Rica and an Atlantic white-sided dolphin (Lagenorhynchus acutus) in the UK. We describe the first report, to our knowledge, of B. ceti-associated meningitis and arthritis in a third species, the shortbeaked common dolphin (Delphinus delphis), in an animal that stranded in the UK. © Wildlife Disease Association 2013.
Identification of the sea ice diatom biomarker IP25 and related lipids in marine mammals: A potential method for investigating regional variations in dietary sources within higher trophic level marine systems
Brown T.A.,University of Plymouth |
Belt S.T.,University of Plymouth |
Ferguson S.H.,Canadian Department of Fisheries and Oceans |
Yurkowski D.J.,University of Windsor |
And 3 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2013
Marine mammals are often the top predators in a given food web; however, since these animals spend much of their time underwater and often away from the coast, this potentially limits our ability to obtain a complete ecological understanding of these important animals, including the determination of their dietary preferences and adaptations. Recently, the analysis of so-called highly branched isoprenoid (HBI) lipids from marine diatoms has provided new insights into the feeding habits of lower trophic level marine animals. In the present study, we extended this approach to higher trophic levels by examining for the presence of these marine diatom HBI biomarkers in seven marine mammal species from both Arctic and temperate regions.Analysis of sub-samples of the livers of Arctic marine mammals revealed the presence of the sea ice diatom biomarker IP25, thus providing evidence for trophic transfer of this lipid from sea ice algae. Our analysis also demonstrated the occurrence of additional HBI lipids in both Arctic and Atlantic marine mammals that are likely indicative of trophic transfer from phytoplanktic diatoms. Although the reasons for the highly variable abundances of the HBIs in individual specimens are uncertain at this stage, the differences in the relative distributions of the individual HBI isomers in mammals from the Arctic and the Atlantic, suggests that these have the potential to provide novel information regarding different dietary sources from the two regions. Further, our analyses demonstrate that HBIs are distributed homogeneously within striped dolphin (Stenella coeruleoalba) liver tissue, thus validating the sub-sampling technique employed for other specimens here. Validation of this sampling technique also provides the necessary confidence to facilitate advancement of the study of HBIs in large marine mammals. © 2013.
PubMed | University of Barcelona, Natural History Museum in London, Coordinadora para o Estudio dos Mamiferos Marinos CEMMA, UK Institute of Zoology and 12 more.
Type: | Journal: Scientific reports | Year: 2016
Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n=929) or biopsied (n=152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB hotspots for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.
Murphy S.,UK Institute of Zoology |
Barber J.L.,Center for Environment |
Learmonth J.A.,University of Aberdeen |
Read F.L.,University of Aberdeen |
And 9 more authors.
PLoS ONE | Year: 2015
Reproductive failure in mammals due to exposure to polychlorinated biphenyls (PCBs) can occur either through endocrine disrupting effects or via immunosuppression and increased disease risk. To investigate further, full necropsies and determination of summed 25 polychlorinated biphenyls congeners (ΣPCBs lipid weight) in blubber were undertaken on 329 UK-stranded female harbour porpoises (1990-2012). In sexually mature females, 25/127 (19.7%) showed direct evidence of reproductive failure (foetal death, aborting, dystocia or stillbirth). A further 21/127 (16.5%) had infections of the reproductive tract or tumours of reproductive tract tissues that could contribute to reproductive failure. Resting mature females (non-lactating or non-pregnant) had significantly higher mean ΣPCBs (18.5 mg/kg) than both lactating (7.5 mg/kg) and pregnant females (6 mg/kg), though not significantly different to sexually immature females (14.0 mg/kg). Using multinomial logistic regression models ΣPCBs was found to be a significant predictor of mature female reproductive status, adjusting for the effects of confounding variables. Resting females were more likely to have a higher PCB burden. Health status (proxied by "trauma" or "infectious disease" causes of death) was also a significant predictor, with lactating females (i.e. who successfully reproduced) more likely to be in good health status compared to other individuals. Based on contaminant profiles (>11 mg/kg lipid), at least 29/60 (48%) of resting females had not offloaded their pollutant burden via gestation and primarily lactation. Where data were available, these non-offloading females were previously gravid, which suggests foetal or newborn mortality. Furthermore, a lower pregnancy rate of 50% was estimated for "healthy" females that died of traumatic causes of death, compared to other populations. Whether or not PCBs are part of an underlying mechanism, we used individual PCB burdens to show further evidence of reproductive failure in the North-east Atlantic harbour porpoise population, results that should inform conservation management. © 2015 Murphy 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.
Baily J.L.,Moredun Research Institute |
Baily J.L.,University of St. Andrews |
Baily J.L.,University of Edinburgh |
Foster G.,Scottish Marine Animal Stranding Scheme |
And 8 more authors.
Environmental Microbiology | Year: 2016
Microbial pollution of the marine environment through land-sea transfer of human and livestock pathogens is of concern. Salmonella was isolated from rectal swabs of free-ranging and stranded grey seal pups (21.1%; 37/175) and compared with strains from the same serovars isolated from human clinical cases, livestock, wild mammals and birds in Scotland, UK to characterize possible transmission routes using pulsed-field gel electrophoresis and multi-locus variable number of tandem repeat analyses. A higher prevalence of Salmonella was found in pups exposed to seawater, suggesting that this may represent a source of this pathogen. Salmonella Bovismorbificans was the most common isolate (18.3% pups; 32/175) and was indistinguishable from isolates found in Scottish cattle. SalmonellaTyphimurium was infrequent (2.3% pups; 4/175), mostly similar to isolates found in garden birds and, in one case, identical to a highly multidrug resistant strain isolated from a human child. SalmonellaHaifa was rare (1.1% pups; 2/175), but isolates were indistinguishable from that of a human clinical isolate. These results suggest that S. Bovismorbificans may circulate between grey seal and cattle populations and that both S. Typhimurium and S. Haifa isolates are shared with humans, raising concerns of microbial marine pollution. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.
PubMed | University Utrecht, Scientific Institute of Public Health WIV ISP, University of Veterinary Medicine Hannover, University of Liège and 6 more.
Type: | Journal: Veterinary parasitology | Year: 2016
The occurrence of the zoonotic protozoan parasite Toxoplasma gondii in marine mammals remains a poorly understood phenomenon. In this study, samples from 589 marine mammal species and 34 European otters (Lutra lutra), stranded on the coasts of Scotland, Belgium, France, The Netherlands and Germany, were tested for the presence of T. gondii. Brain samples were analysed by polymerase chain reaction (PCR) for detection of parasite DNA. Blood and muscle fluid samples were tested for specific antibodies using a modified agglutination test (MAT), a commercial multi-species enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IFA). Out of 193 animals tested by PCR, only two harbour porpoise (Phocoena phocoena) cerebrum samples, obtained from animals stranded on the Dutch coast, tested positive. The serological results showed a wide variation depending on the test used. Using a cut-off value of 1/40 dilution in MAT, 141 out of 292 animals (41%) were positive. Using IFA, 30 out of 244 tested samples (12%) were positive at a 1/50 dilution. The commercial ELISA yielded 7% positives with a cut-off of the sample-to-positive (S/P) ratio50; and 12% when the cut-off was set at S/P ratio20. The high number of positives in MAT may be an overestimation due to the high degree of haemolysis of the samples and/or the presence of lipids. The ELISA results could be an underestimation due to the use of a multispecies conjugate. Our results confirm the presence of T. gondii in marine mammals in The Netherlands and show exposure to the parasite in both the North Sea and the Eastern Atlantic Ocean. We also highlight the limitations of the tests used to diagnose T. gondii in stranded marine mammals.
PubMed | Moredun Research Institute, Scottish Marine Animal Stranding Scheme, Royal Infirmary, University of St. Andrews and Royal Zoological Society of Scotland
Type: Journal Article | Journal: Environmental microbiology | Year: 2016
Microbial pollution of the marine environment through land-sea transfer of human and livestock pathogens is of concern. Salmonella was isolated from rectal swabs of free-ranging and stranded grey seal pups (21.1%; 37/175) and compared with strains from the same serovars isolated from human clinical cases, livestock, wild mammals and birds in Scotland, UK to characterize possible transmission routes using pulsed-field gel electrophoresis and multi-locus variable number of tandem repeat analyses. A higher prevalence of Salmonella was found in pups exposed to seawater, suggesting that this may represent a source of this pathogen. Salmonella Bovismorbificans was the most common isolate (18.3% pups; 32/175) and was indistinguishable from isolates found in Scottish cattle. Salmonella Typhimurium was infrequent (2.3% pups; 4/175), mostly similar to isolates found in garden birds and, in one case, identical to a highly multidrug resistant strain isolated from a human child. Salmonella Haifa was rare (1.1% pups; 2/175), but isolates were indistinguishable from that of a human clinical isolate. These results suggest that S. Bovismorbificans may circulate between grey seal and cattle populations and that both S. Typhimurium and S. Haifa isolates are shared with humans, raising concerns of microbial marine pollution.