Biological threats and environmental pollutants, a lethal mixture for mediterranean cetaceans?

The possible existence of any cause–effect relationships between the concentrations of organochlorines (OCs) and the presence of Morbillivirus and Toxoplasma gondii infections was investigated in both free-living and stranded specimens of Stenella coeruleoalba, Tursiops truncatus, Globicephala melas, Balaenoptera physalus and Physeter macrocephalus from the Mediterranean Sea. High blubber concentrations of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) were recorded in free-ranging G. melas. Tissue concentrations of PCBs and DDT in stranded T. truncatus (367 lipid weight (l.w.) and 143.7 mg/kg l.w., respectively) and S. coeruleoalba (139.9 l.w.; 92.9 mg/kg l.w.) were beyond the PCB threshold value for the appearance of adverse effects in marine mammals. Evidence of T. gondii infection was molecularly detected in three S. coeruleoalba and six T. truncatus.

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Bones as biofuel: a review of whale bone composition with implications for deep-sea biology and palaeoanthropology

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2010.1267 ◽

2010 ◽

Vol 278 (1702) ◽

pp. 9-17 ◽

Cited By ~ 33

Author(s):

Nicholas D. Higgs ◽

Crispin T. S. Little ◽

Adrian G. Glover

Keyword(s):

Soft Tissue ◽

Deep Sea ◽

Oil Content ◽

Archaeological Sites ◽

Physeter Macrocephalus ◽

Balaenoptera Physalus ◽

Stenella Coeruleoalba ◽

Striped Dolphin ◽

Oil Reserves ◽

Different Parts

Whales are unique among vertebrates because of the enormous oil reserves held in their soft tissue and bone. These ‘biofuel’ stores have been used by humans from prehistoric times to more recent industrial-scale whaling. Deep-sea biologists have now discovered that the oily bones of dead whales on the seabed are also used by specialist and generalist scavenging communities, including many unique organisms recently described as new to science. In the context of both cetacean and deep-sea invertebrate biology, we review scientific knowledge on the oil content of bone from several of the great whale species: Balaenoptera musculus, Balaenoptera physalus , Balaenoptera borealis , Megaptera novaeangliae, Eschrichtius robustus , Physeter macrocephalus and the striped dolphin, Stenella coeruleoalba . We show that data collected by scientists over 50 years ago during the heyday of industrial whaling explain several interesting phenomena with regard to the decay of whale remains. Variations in the lipid content of bones from different parts of a whale correspond closely with recently observed differences in the taphonomy of deep-sea whale carcasses and observed biases in the frequency of whale bones at archaeological sites.

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Marine mammals are natural hosts of Oceanivirga salmonicida, a bacterial pathogen of Atlantic salmon

Diseases of Aquatic Organisms ◽

10.3354/dao03478 ◽

2020 ◽

Vol 139 ◽

pp. 161-174

Author(s):

R Palmer ◽

GTA Fleming ◽

S Glaeser ◽

T Semmler ◽

A Flamm ◽

...

Keyword(s):

16S Rrna ◽

Atlantic Salmon ◽

16S Rrna Gene ◽

Marine Mammals ◽

Rrna Gene ◽

Bacterial Disease ◽

Common Dolphin ◽

Stenella Coeruleoalba ◽

Striped Dolphin ◽

Natural Hosts

During 1992 and 1993, a bacterial disease occurred in a seawater Atlantic salmon Salmo salar farm, causing serious mortalities. The causative agent was subsequently named as Oceanivirga salmonicida, a member of the Leptotrichiaceae. Searches of 16S rRNA gene sequence databases have shown sequence similarities between O. salmonicida and uncultured bacterial clones from the digestive tracts of marine mammals. In the current study, oral samples were taken from stranded dolphins (common dolphin Delphinus delphis, striped dolphin Stenella coeruleoalba) and healthy harbour seals Phoca vitulina. A bacterium with growth characteristics consistent with O. salmonicida was isolated from a common dolphin. The isolate was confirmed as O. salmonicida, by comparisons to the type strain, using 16S rRNA gene, gyrB, groEL, and recA sequence analyses, average nucleotide identity analysis, and MALDI-TOF mass spectrometry. Metagenomic analysis indicated that the genus Oceanivirga represented a significant component of the oral bacterial microbiomes of the dolphins and seals. However, sequences consistent with O. salmonicida were only found in the dolphin samples. Analyses of marine mammal microbiome studies in the NCBI databases showed sequences consistent with O. salmonicida from the common dolphin, striped dolphin, bottlenose dolphin Tursiops truncatus, humpback whale Megaptera novaeangliae, and harbour seal. Sequences from marine environmental studies in the NCBI databases showed no sequences consistent with O. salmonicida. The findings suggest that several species of marine mammals are natural hosts of O. salmonicida.

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Corneal anatomy of marine mammals

Canadian Journal of Zoology ◽

10.1139/z93-320 ◽

1993 ◽

Vol 71 (11) ◽

pp. 2282-2290 ◽

Cited By ~ 3

Author(s):

M. T. Pardue ◽

J. G. Sivak ◽

K. M. Kovacs

Keyword(s):

Marine Mammals ◽

Equatorial Region ◽

Balaenoptera Acutorostrata ◽

Marine Habitat ◽

Corneal Surface ◽

Balaenoptera Physalus ◽

Phoca Groenlandica ◽

Minke Whales ◽

Transmission Electron ◽

Ultrathin Sections

The corneal anatomy of fin whales (Balaenoptera physalus), minke whales (Balaenoptera acutorostrata), harp seals (Phoca groenlandica), ringed seals (Phoca hispida), and bearded seals (Eriganthus barbatus) was examined to determine if marine mammals have evolved specialized corneas for life in a marine habitat. One to seven eyes of each species were analyzed: paraffin sections stained with haematoxylin and eosin for light microscopy; and ultrathin sections for transmission electron microscopy. All corneas contain the five typical mammalian layers: epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. The corneas of these marine mammals are thicker than human corneas because of a thicker stromal layer. The other layers are thinner than those found in humans, except for the epithelial layer in the bearded seal and the cetaceans where it may provide extra protection for the eye during feeding behaviour. The epithelial cells in all corneas studied have an abundance of tonofilaments, which may strengthen the cells and distribute force across the corneal surface. No special organization of collagen fibrils was found in the stroma that would offer protection from ultraviolet radiation or glare for pinnipeds when on ice. The thickness of the sclera in the cetaceans may serve to hold the inner globe of the eye in an elliptical shape, while the thinning of the sclera in the equatorial region in pinnipeds may flatten the eye in air to reduce aerial myopia.

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Severity Scoring of Behavioral Responses of Sperm Whales (Physeter macrocephalus) to Novel Continuous versus Conventional Pulsed Active Sonar

Journal of Marine Science and Engineering ◽

10.3390/jmse9040444 ◽

2021 ◽

Vol 9 (4) ◽

pp. 444

Author(s):

Charlotte Curé ◽

Saana Isojunno ◽

Marije L. Siemensma ◽

Paul J. Wensveen ◽

Célia Buisson ◽

...

Keyword(s):

Behavioral Responses ◽

Physeter Macrocephalus ◽

Vital Rates ◽

Sperm Whales ◽

Experimental Conditions ◽

Active Sonar ◽

Lower Amplitude ◽

Pilot Whales ◽

New Generation ◽

Free Ranging

Controlled exposure experiments (CEEs) have demonstrated that naval pulsed active sonar (PAS) can induce costly behavioral responses in cetaceans similar to antipredator responses. New generation continuous active sonars (CAS) emit lower amplitude levels but more continuous signals. We conducted CEEs with PAS, CAS and no-sonar control on free-ranging sperm whales in Norway. Two panels blind to experimental conditions concurrently inspected acoustic-and-movement-tag data and visual observations of tagged whales and used an established severity scale (0–9) to assign scores to putative responses. Only half of the exposures elicited a response, indicating overall low responsiveness in sperm whales. Responding whales (10 of 12) showed more, and more severe responses to sonar compared to no-sonar. Moreover, the probability of response increased when whales were previously exposed to presence of predatory and/or competing killer or long-finned pilot whales. Various behavioral change types occurred over a broad range of severities (1–6) during CAS and PAS. When combining all behavioral types, the proportion of responses to CAS was significantly higher than no-sonar but not different from PAS. Responses potentially impacting vital rates i.e., with severity ≥4, were initiated at received cumulative sound exposure levels (dB re 1 μPa2 s) of 137–177 during CAS and 143–181 during PAS.

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Vitamin A physiology in the precocious harbour seal (Phoca vitulina): a tissue-based biomarker approach

Canadian Journal of Zoology ◽

10.1139/z02-152 ◽

2002 ◽

Vol 80 (9) ◽

pp. 1511-1519 ◽

Cited By ~ 19

Author(s):

Lizzy Mos ◽

Peter S Ross

Keyword(s):

Vitamin A ◽

Marine Mammals ◽

Relevant Information ◽

Phoca Vitulina ◽

Retinyl Palmitate ◽

Harbour Seal ◽

Natural Processes ◽

Reproductive Endocrine ◽

Positive Correlations ◽

Free Ranging

Vitamin A is a nutrient essential to all mammals for growth and development, as well as for the maintenance of reproductive, endocrine, and immune systems. Environmental contaminant-related disruption of vitamin A has been observed in many wildlife species and can therefore be used as a biomarker of toxic effects. However, the natural processes regulating vitamin A uptake, storage, and distribution among compartments are poorly understood in marine mammals. In this study, 20 young healthy harbour seals (Phoca vitulina) were captured to establish a compartment-based model providing a foundation for a mechanistic understanding of vitamin A physiology and disruption. Vitamin A (retinol, retinyl palmitate, and (or) retinoic acid) was quantified in blood plasma and in biopsy samples of liver, blubber, and skin. Although the highest concentrations of vitamin A were found in liver, blubber represents a more important storage depot, with an estimated 66% of the total retinoid content of the compartments measured. We suggest that vitamin A physiology in the precocious harbour seal has evolved to deal with high vitamin A availability during a short nursing period and to sustain growth during the postweaning fast. Positive correlations in vitamin A concentrations among liver, blubber, and skin support the use of less invasive biopsy sampling of just blubber or skin, which can provide physiologically relevant information in biomarker studies of free-ranging marine mammals.

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Fatal Streptococcus iniae Infection in a Juvenile Free-Ranging Short-Beaked Common Dolphin (Delphinus delphis)

Animals ◽

10.3390/ani11113123 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3123

Author(s):

Rebecca Souter ◽

Anne-Lise Chaber ◽

Ken Lee ◽

Aaron Machado ◽

Jia Lam ◽

...

Keyword(s):

Marine Mammals ◽

Skin Lesions ◽

Streptococcus Iniae ◽

Common Dolphin ◽

Farmed Fish ◽

Fish Stocks ◽

Zoonotic Pathogen ◽

Delphinus Delphis ◽

Source Of Infection ◽

Free Ranging

Streptococcus iniae (S. iniae) is a significant aquatic pathogen of farmed fish species, important zoonotic pathogen, and reported cause of disease in captive Amazon River dolphins (Inia geoffrensis) and a bottlenose dolphin (Tursiops truncatus). Here we report S. iniae as the cause of subcutaneous abscesses, sepsis and mortality in a juvenile free-ranging short-beaked common dolphin (Delphinus delphis) found deceased on a metropolitan Australian beach. Body surfaces were covered by multifocal, depressed, deep, irregular cutaneous ulcerations, which microscopically were characterised by ruptured subcutaneous abscesses with intralesional cocci. Routine microbiological investigations revealed a heavy growth of beta-haemolytic Streptococcus sp. identified as Streptococcus iniae in skin lesions as well as from heart blood, the latter supportive of sepsis. Tissues were negative for cetacean morbillivirus and no other disease processes were identified. S. iniae has not been reported in free-ranging marine mammals, nor in Australian delphinids, previously. More notably a pathogen of captive animals, this case report identifies S. iniae as a pathogen of wild dolphins also. In addition to expanding the host reservoir of a significant zoonotic pathogen, determining the source of infection as well as possible consequences for other marine mammals and wild and intensive fish stocks warrants further investigations.

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Molecular survey of Besnoitia spp. (Apicomplexa) in faeces from European wild mesocarnivores in Spain. Short running title: Molecular survey of Besnoitia spp in faeces from wild carnivores.

10.22541/au.162083175.56553530/v1 ◽

2021 ◽

Author(s):

David González-Barrio ◽

Pamela C. Köster ◽

Miguel Habela ◽

Manuel Martín-Pérez ◽

José Fernández-García ◽

...

Keyword(s):

Definitive Host ◽

Red Foxes ◽

Besnoitia Besnoiti ◽

Free Living ◽

Wild Carnivores ◽

Molecular Survey ◽

Faecal Samples ◽

Bovine Besnoitiosis ◽

Western Spain ◽

Free Ranging

Numerous studies have unsuccessfully tried to unravel the definitive host of the coccidian parasite Besnoitia besnoiti. Cattle infections by B. besnoiti cause a chronic and debilitating condition called bovine besnoitiosis that has emerged in Europe during the last two decades, mainly due to limitations in its control associated to the absence of vaccines and therapeutical tools. Although the exact transmission pathway of B. besnoiti is currently unknown, it is assumed that the parasite might have an indirect life cycle with a carnivore as definitive host. Current lack of studies in wildlife might underestimate the importance of free-living species in the epidemiology of B. besnoiti. Thus, the aim of the present study is to assess the presence of Besnoitia spp. in free-ranging mesocarnivores in Spain. DNA was searched by PCR on faeces collected from wild carnivores as a first approach to determine which species could be considered as potential definitive host candidates in further research. For this purpose, a total of 352 faecal samples from 12 free-living wild carnivore species belonging to the Canidae, Felidae, Herpestidae, Mustelidae, Procyonidae, and Viverridae families were collected in seven Spanish regions. PCR testing showed that Besnoitia spp. DNA was present in four faecal samples from red foxes collected in western Spain, an area with the greatest density of extensively reared cattle and associated to high incidence of bovine besnoitiosis in the country. To date, this is the first report of a Besnoitia besnoiti-like sequence (99.57% homology) from carnivore faeces in a worldwide context. Red foxes might contribute to the epidemiology of B. besnoiti, although further studies, mostly based on bioassay, would be needed to elucidate the accuracy and extent of these interesting findings.

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Occurrence of anthropozoonotic parasitic infections and faecal microbes in free-ranging sperm whales (Physeter macrocephalus) from the Mediterranean Sea

Parasitology Research ◽

10.1007/s00436-018-5942-3 ◽

2018 ◽

Vol 117 (8) ◽

pp. 2531-2541 ◽

Cited By ~ 8

Author(s):

Carlos Hermosilla ◽

J. Hirzmann ◽

L. M. R. Silva ◽

J. M. Brotons ◽

M. Cerdà ◽

...

Keyword(s):

Mediterranean Sea ◽

Parasitic Infections ◽

Physeter Macrocephalus ◽

Sperm Whales ◽

The Mediterranean ◽

Free Ranging

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Flight Energetics of Free-Living Sooty Terns

The Auk ◽

10.1093/auk/101.2.288 ◽

1984 ◽

Vol 101 (2) ◽

pp. 288-294 ◽

Cited By ~ 52

Author(s):

Elizabeth N. Flint ◽

Kenneth A. Nagy

Keyword(s):

Metabolic Rate ◽

Standard Metabolic Rate ◽

Co2 Production ◽

Doubly Labeled Water ◽

Free Living ◽

Aspect Ratios ◽

Flight Energetics ◽

Flight Metabolism ◽

Sooty Tern ◽

Free Ranging

Abstract The CO2 production of free-ranging Sooty Terns (Sterna fuscata) was measured using doubly labeled water (HTO-18). Metabolic rate during flight was determined to be 4.8 times standard metabolic rate (SMR). This value is much lower than estimates of flight metabolism predicted from previously published equations. Observations of these birds at sea indicate that flapping flight predominated at the windspeeds (0-5 m/s) that prevailed during our measurement periods, so factors other than gliding must account for the comparatively low flight metabolism we measured. Sooty Tern flight metabolism is similar to that of some other birds, such as swallows and swifts, that also have high aspect ratios and low wing loadings.

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