scholarly journals Tooth Microwear Texture in the Eastern Atlantic Harbour Seals (Phoca vitulina vitulina) of the German Wadden Sea and Its Implications for Long Term Dietary and Ecosystem Changes

2021 ◽  
Vol 9 ◽  
Author(s):  
Elehna Bethune ◽  
Ellen Schulz-Kornas ◽  
Kristina Lehnert ◽  
Ursula Siebert ◽  
Thomas M. Kaiser
Keyword(s):  
Health Status ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Wadden Sea ◽  
Anthropogenic Impacts ◽  
Phoca Vitulina ◽  
Dental Microwear ◽  
Future Health ◽  
Terrestrial Mammals ◽  
Harbour Seals

Marine mammals are increasingly threatened in their habitat by various anthropogenic impacts. This is particularly evident in prey abundance. Understanding the dietary strategies of marine mammal populations can help predict implications for their future health status and is essential for their conservation. In this study we provide a striking example of a new dietary proxy in pinnipeds to document marine mammal diets using a dental record. In this novel approach, we used a combination of 49 parameters to establish a dental microwear texture (DMTA) as a dietary proxy of feeding behaviour in harbour seals. This method is an established approach to assess diets in terrestrial mammals, but has not yet been applied to pinnipeds. Our aim was to establish a protocol, opening DMTA to pinnipeds by investigating inter- and intra-individual variations. We analysed the 244 upper teeth of 78 Atlantic harbour seals (Phoca vitulina vitulina). The specimens were collected in 1988 along the North Sea coast (Wadden Sea, Germany) and are curated by the Zoological Institute of Kiel University, Germany. An increasing surface texture roughness from frontal to distal teeth was found and related to different prey processing biomechanics. Ten and five year old individuals were similar in their texture roughness, whereas males and females were similar to each other with the exception of their frontal dentition. Fall and summer specimens also featured no difference in texture roughness. We established the second to fourth postcanine teeth as reference tooth positions, as those were unaffected by age, sex, season, or intra-individual variation. In summary, applying indirect dietary proxies, such as DMTA, will allow reconstructing dietary traits of pinnipeds using existing skeletal collection material. Combining DMTA with time series analyses is a very promising approach to track health status in pinniped populations over the last decades. This approach opens new research avenues and could help detect dietary shifts in marine environments in the past and the future.

Environmental pollutants and marine mammal health: The potential impact of hydrocarbons and halogenated hydrocarbons on immune system dysfunction

2020 ◽  
pp. 223-248
Author(s):  
David Busbee ◽  
Ian Tizard ◽  
Jeffrey Sroit ◽  
Davide Ferrirc ◽  
Ellen Orr-reeves
Keyword(s):  
Immune System ◽  
Food Chain ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Large Scale ◽  
Environmental Pollutants ◽  
Halogenated Hydrocarbons ◽  
Mechanisms Of Toxicity ◽  
Terrestrial Mammals ◽  
Immune System Dysfunction

This paper provides a detailed review of the immunotoxicological effects of environmental pollutants on the health of marine mammals, particularly in relation to their impact on the immune system and mechanisms of toxicity. Environmental pollutants are increasingly implicated (both directly and indirectly) with the onset of infectious disease and related mortality incidents in marine mammals,. The release of chemicals into the marine environment and the subsequent bioaccumulation up the food chain may pose a serious threat to marine mammals inhabiting contaminated areas; this has been documented in various studies of pollutant concentrations in tissue samples and large scale mass mortalities. Data correlating pollutant residues with altered reproductive/developmental states, and immune system dysfunction in particular, are reported for terrestrial mammals and suggest a similar association in marine mammals. Immunology is emphasised as a tool for assessing marine mammal health using quantitative and qualitative techniques to establish the effects of chemical pollutants. This has become increasingly important in relation to the subsequent dangers that may be posed to humans through any indirect exposure via the food chain.

Spectral-tuning mechanisms of marine mammal rhodopsins and correlations with foraging depth

2000 ◽  
Vol 17 (5) ◽  
pp. 781-788 ◽  
Author(s):  
JEFFRY I. FASICK ◽  
PHYLLIS R. ROBINSON
Keyword(s):  
Amino Acid ◽  
Marine Mammal ◽  
Molecular Basis ◽  
Marine Mammals ◽  
Visual Pigments ◽  
Amino Acid Substitutions ◽  
Spectral Tuning ◽  
Long Wavelength ◽  
Terrestrial Mammals ◽  
Deep Diving

It has been observed that deep-foraging marine mammals have visual pigments that are blue shifted in terms of their wavelength of maximal absorbance (λmax) when compared to analogous pigments from terrestrial mammals. The mechanisms underlying the spectral tuning of two of these blue-shifted pigments have recently been elucidated and depend on three amino acid substitutions (83Asn, 292Ser, and 299Ser) in dolphin rhodopsin, but only one amino acid substitution (308Ser) in the dolphin long-wavelength-sensitive pigment. The objective of this study was to investigate the molecular basis for changes in the spectral sensitivity of rod visual pigments from seven distantly related marine mammals. The results show a relationship between blue-shifted rhodopsins (λmax ≤ 490 nm), deep-diving foraging behavior, and the substitutions 83Asn and 292Ser. Species that forage primarily near the surface in coastal habitats have a rhodopsin with a λmax similar to that of terrestrial mammals (500 nm) and possess the substitutions 83Asp and 292Ala, identical to rhodopsins from terrestrial mammals.

scholarly journals Options for modulating intra-specific competition in colonial pinnipeds: the case of harbour seals (Phoca vitulina) in the Wadden Sea

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e957 ◽  
Author(s):  
Rory P. Wilson ◽  
Nikolai Liebsch ◽  
Agustina Gómez-Laich ◽  
William P. Kay ◽  
Andrew Bone ◽  
...  
Keyword(s):  
Wadden Sea ◽  
Phoca Vitulina ◽  
Harbour Seals

scholarly journals Treatment of naturally acquired demodectic mange with amitraz in two harbour seals (Phoca vitulina)

2015 ◽  
Vol 63 (3) ◽  
pp. 352-357 ◽  
Author(s):  
Kyoo-Tae Kim ◽  
Seung-Hun Lee ◽  
Dongmi Kwak
Keyword(s):  
Successful Treatment ◽  
Marine Mammals ◽  
Clinical Signs ◽  
Skin Lesions ◽  
Phoca Vitulina ◽  
Aetiological Agent ◽  
Harbour Seals ◽  
Causative Agents ◽  
Pure Cultures

Two male harbour seals (Phoca vitulina; 33 and 35 years old, respectively), housed since 2002 at a zoo for exhibition purposes, developed severe, multifocal and diffuse skin lesions. Skin scrapings and microscopy for parasites as well as pure cultures for bacteria and dermatophytes were carried out to identify the aetiological agent. Skin scrapings showed that lesions appearing on the seals were caused by an infestation of Demodex mites, which is uncommon in marine mammals, and were not due to other causative agents (parasites, bacteria or dermatophytes). Treatment with amitraz (0.01%) once a week for three weeks and with ampicillin (10 mg/kg SID per os) for six days eliminated the mites and resolved the clinical signs of demodectic mange in the harbour seals. The purpose of this report is to describe the successful treatment of naturally acquired demodectic mange with amitraz in harbour seals.

Metabolic rates of seals and whales

1986 ◽  
Vol 64 (2) ◽  
pp. 279-284 ◽  
Author(s):  
D. M. Lavigne ◽  
S. Innes ◽  
G. A. J. Worthy ◽  
K. M. Kovacs ◽  
O. J. Schmitz ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Food Consumption ◽  
Marine Mammal ◽  
Critical Review ◽  
Comparative Studies ◽  
Marine Mammals ◽  
Metabolic Rates ◽  
Sea Lions ◽  
Terrestrial Mammals ◽  
Fur Seals

A critical review of metabolic rate determinations for pinnipeds (seals, sea lions, fur seals, and walrus) and cetaceans (whales, dolphins, and porpoises) does not support the widely accepted generalization that they have higher metabolic rates than terrestrial mammals of similar size. This finding necessitates a rethinking of the thermoregulatory adaptations of these marine mammals for an aquatic existence and has important implications in comparative studies of mammals, which frequently omit marine forms because they are perceived to be "different" from other mammals. It also suggests that numerous studies have overestimated food consumption by marine mammal populations.

Population development of harbour seals Phoca vitulina in the Wadden Sea after the 1988 virus epizootic

1997 ◽  
Vol 38 (1-2) ◽  
pp. 161-168 ◽  
Author(s):  
Peter J.H. Reijnders ◽  
Edith H. Ries ◽  
Svend Tougaard ◽  
Niels Nørgaard ◽  
Günter Heidemann ◽  
...  
Keyword(s):  
Wadden Sea ◽  
Phoca Vitulina ◽  
Population Development ◽  
Harbour Seals

The importance of the North Sea for winter dispersal of harbour seals Phoca vitulina from the Wadden Sea

1997 ◽  
Vol 81 (1-2) ◽  
pp. 97-102 ◽  
Author(s):  
Mardik F. Leopold ◽  
Bert van der Werf ◽  
Edith H. Ries ◽  
Peter J.H. Reijnders
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Phoca Vitulina ◽  
The North ◽  
Harbour Seals ◽  
The North Sea

scholarly journals Earlier pupping in harbour seals, Phoca vitulina

2010 ◽  
Vol 6 (6) ◽  
pp. 854-857 ◽  
Author(s):  
Peter J. H. Reijnders ◽  
Sophie M. J. M. Brasseur ◽  
Erik H. W. G. Meesters
Keyword(s):  
Life History Traits ◽  
Annual Variation ◽  
Wadden Sea ◽  
Phoca Vitulina ◽  
Birth Date ◽  
Embryonic Diapause ◽  
Potential Mechanism ◽  
Annual Reproductive Cycle ◽  
Harbour Seals ◽  
Large Predator

The annual reproductive cycle of most seal species is characterized by a tight synchrony of births. Typically, timing of birth shows little inter-annual variation. Here, however we show that harbour seals Phoca vitulina from the Wadden Sea (southeast North Sea) have shortened their yearly cycle, moving parturition to earlier dates since the early 1970s. Between 1974 and 2009, the birth date of harbour seals shifted on average by −0.71 d yr −1 , three and a half weeks (25 days) earlier, in the Dutch part of the Wadden Sea. Pup counts available for other parts of the Wadden Sea were analysed, showing a similar shift. To elucidate potential mechanism(s) for this shift in pupping phenology, possible changes in population demography, changes in maternal life-history traits and variations in environmental conditions were examined. It was deduced that the most likely mechanism was a shortening of embryonic diapause. We hypothesize that this could have been facilitated by an improved forage base, e.g. increase of small fishes, attributable to overfishing of large predator fishes and size-selective fisheries.

scholarly journals Pinniped- and Cetacean-Derived ETosis Contributes to Combating Emerging Apicomplexan Parasites (Toxoplasma gondii, Neospora caninum) Circulating in Marine Environments

Biology ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 12 ◽  
Author(s):  
Rodolfo Villagra-Blanco ◽  
Liliana Silva ◽  
Iván Conejeros ◽  
Anja Taubert ◽  
Carlos Hermosilla
Keyword(s):  
Toxoplasma Gondii ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Nuclear Dna ◽  
Neospora Caninum ◽  
Mammalian Species ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Polymorphonuclear Neutrophils ◽  
Apicomplexan Parasites ◽  
Terrestrial Mammals

Leukocytes play a major role in combating infections either by phagocytosis, release of antimicrobial granules, or extracellular trap (ET) formation. ET formation is preceded by a certain leukocyte cell death form, known as ETosis, an evolutionarily conserved mechanism of the innate immune system also observed in marine mammals. Besides several biomolecules and microbial stimuli, marine mammal ETosis is also trigged by various terrestrial protozoa and metazoa, considered nowadays as neozoan parasites, which are circulating in oceans worldwide and causing critical emerging marine diseases. Recent studies demonstrated that pinniped- and cetacean-derived polymorphonuclear neutrophils (PMNs) and monocytes are able to form different phenotypes of ET structures composed of nuclear DNA, histones, and cytoplasmic peptides/proteases against terrestrial apicomplexan parasites, e.g., Toxoplasma gondii and Neospora caninum. Detailed molecular analyses and functional studies proved that marine mammal PMNs and monocytes cast ETs in a similar way as terrestrial mammals, entrapping and immobilizing T. gondii and N. caninum tachyzoites. Pinniped- and cetacean leukocytes induce vital and suicidal ETosis, with highly reliant actions of nicotinamide adenine dinucleotide phosphate oxidase (NOX), generation of reactive oxygen species (ROS), and combined mechanisms of myeloperoxidase (MPO), neutrophil elastase (NE), and DNA citrullination via peptidylarginine deiminase IV (PAD4).This scoping review intends to summarize the knowledge on emerging protozoans in the marine environment and secondly to review limited data about ETosis mechanisms in marine mammalian species.

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