scholarly journals Laryngeal and soft palate valving in the harbour seal (Phoca vitulina)

2020 ◽  
Vol 223 (20) ◽  
pp. jeb230201
Author(s):  
Arlo Adams ◽  
Wayne Vogl ◽  
Camilla Dawson ◽  
Stephen Raverty ◽  
Martin Haulena ◽  
...  
Keyword(s):  
Soft Palate ◽  
Marine Mammals ◽  
Vocal Folds ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Upper Aerodigestive Tract ◽  
Laryngeal Inlet ◽  
Harbour Seals ◽  
Lateral Margins ◽  
And Function

ABSTRACTEffective ‘valving’ in the upper aerodigestive tract (UAT) is essential to temporarily separate the digestive and respiratory pathways. Marine mammals are largely dedicated to feeding underwater, and in many cases swallowing prey whole. In seals, little work has been done to explore the anatomy and function of the UAT in the context of valving mechanisms that function to separate food and air pathways. Here we use videofluoroscopy, gross dissection, histology and computed tomography (CT) renderings to explore the anatomy of the larynx and soft palate in the harbour seal (Phoca vitulina), and generate models for how valving mechanisms in the head and neck may function during breathing, phonating, diving and swallowing. Harbour seals have an elevated larynx and the epiglottis may rise above the level of the soft palate, particularly in pups when sucking. In addition, the corniculate and arytenoid cartilages with associated muscles form most of the lateral margins of the laryngeal inlet and vestibule, and move independently to facilitate airway closure. The corniculate cartilages flex over the laryngeal inlet beneath the epiglottis to completely close the laryngeal vestibule and inlet. The vocal folds are thick and muscular and the medial margin of the folds contains a small vocal ligament. The soft palate has well-defined levator veli palatini muscles that probably function to elevate the palate and close the pharyngeal isthmus during feeding. Our results support the conclusion that harbour seals have evolved UAT valving mechanisms as adaptations to a marine environment that are not seen in terrestrial carnivores.

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

2002 ◽  
Vol 80 (9) ◽  
pp. 1511-1519 ◽  
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.

scholarly journals Livestock-associated meticillin-resistant Staphylococcus aureus in a young harbour seal (Phoca vitulina) with endocarditis

2019 ◽  
Vol 7 (3) ◽  
pp. e000886 ◽  
Author(s):  
Ana Rubio-Garcia ◽  
John W A Rossen ◽  
Jaap A Wagenaar ◽  
Alex W Friedrich ◽  
Jan H van Zeijl
Keyword(s):  
Staphylococcus Aureus ◽  
Marine Mammals ◽  
Aortic Wall ◽  
Bacterial Culture ◽  
Histopathological Examination ◽  
Phoca Vitulina ◽  
Antimicrobial Treatment ◽  
Harbour Seal ◽  
First Time ◽  
Secondary Bacterial Pneumonia

A five-month-old male harbour seal was admitted for rehabilitation to the Sealcentre Pieterburen on November 16, 2015. During initial veterinary examination parasitic pneumonia and secondary bacterial pneumonia were suspected. Therefore, the seal received antiparasitic and antimicrobial treatment and appeared to recover but died unexpectedly after several weeks. Postmortem examination revealed a perforation in the aortic wall and histopathological examination of the aorta revealed mural necrosis with haemorrhage and suppurative to mixed inflammation. Bacterial culture resulted in isolation of a meticillin-resistant Staphylococcus aureus (MRSA) from the pericardial effusion. Subsequent culture of rectal swabs collected at arrival and during rehabilitation showed that the animal was already colonised with MRSA when admitted to the Sealcentre. MRSA has been isolated from marine mammals before, however, to our knowledge this is the first report of MRSA-associated endocarditis in seals and the first time that livestock-associated MRSA is reported in seals.

Comparison of the healing process in hot and cold brands applied to harbour seal pups (Phoca vitulina)

2006 ◽  
Vol 33 (5) ◽  
pp. 361 ◽  
Author(s):  
Pierre-Yves Daoust ◽  
G. Mark Fowler ◽  
Wayne T. Stobo
Keyword(s):  
Healing Rate ◽  
Healing Process ◽  
Phoca Vitulina ◽  
Hair Follicles ◽  
Harbour Seal ◽  
Short Term ◽  
Long Distance ◽  
Macroscopic Appearance ◽  
Short Term Study ◽  
Harbour Seals

Hot branding has been used for many years by researchers to identify seals from a long distance. In livestock, cold branding has been proposed as an alternative because it is thought to be less painful. The purpose of this study was to compare the healing process of hot and cold brands applied to harbour seal pups (Phoca vitulina). A total of 306 animals was branded with a unique set of four characters: three applied for 3–5 s with an iron heated to 500°C, and one applied for either 10 or 20 s with an iron frozen to –175°C. At three subsequent times over 10 weeks, 43, 41 and 51 animals, respectively, were recaptured, the macroscopic appearance of their brands recorded, and biopsies taken for microscopic examination. Cold brands had a faster healing rate than hot brands. However, they resulted in less destruction of hair follicles, and cold brands applied for 20 s caused more depigmentation. Regrowth of hair follicles could subsequently obscure brands, while depigmentation reduces the contrast between the brand and the surrounding fur. Cold brands applied for 20 s also caused more extensive deep vascular damage, which subsequently may have resulted in deeper wounds in some of these brands. Yet, macroscopically, other cold brands, or portions thereof, were almost invisible. On the basis of this short-term study, the technique of cold branding that we used in harbour seals does not appear to be as reliable as that of hot branding to provide permanent legible brands.

scholarly journals Vulnerability of harbour seals, Phoca vitulina, to transient industrial activities in the Strait of Dover

2005 ◽  
Vol 85 (4) ◽  
pp. 1015-1016 ◽  
Author(s):  
Laurent J.J. Seuront ◽  
Perrine Prinzivalli
Keyword(s):  
Interannual Variability ◽  
Industrial Wastewater ◽  
Anthropogenic Activities ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Industrial Activities ◽  
Dramatic Decline ◽  
Harbour Seals ◽  
Seal Population ◽  
Number Of Individuals

The abundance of the harbour seal (Phoca vitulina) was recorded on a tidal bar in the Dover Strait off Calais, over a six-year period between 1999 and 2004. Despite clear seasonal and interannual variability in the number of individuals hauled out on the bar, underwater activities devoted to the installation of industrial wastewater pipes conducted during seven weeks 1 km away from the bar led to a dramatic decline in the number of seals hauling out. A full 19 months after the end of the operations the harbour seal population had not recovered their initial abundance. The results of this study have critical consequences on the conservation of P. vitulina in areas impacted by anthropogenic activities.

scholarly journals Introduction: The harbour seal (Phoca vitulina) - a global perspective

2010 ◽  
Vol 8 ◽  
pp. 7 ◽  
Author(s):  
Arne Bjørge ◽  
Geneviève Desportes ◽  
Gordon T Waring ◽  
Aqqalu Rosing-Asvid
Keyword(s):  
North Atlantic ◽  
Phoca Vitulina ◽  
Global Perspective ◽  
Harbour Seal ◽  
The North ◽  
Harbour Seals ◽  
The North Atlantic ◽  
The Baltic

Introduction to Volume 8: Harbour seals in the North Atlantic and the Baltic 

scholarly journals Observations on seals on the island of Surtsey in the period 1980-2012

2015 ◽  
Vol 13 ◽  
pp. 41-43
Author(s):  
Erlingur Hauksson
Keyword(s):  
Breeding Site ◽  
Phoca Vitulina ◽  
The Other ◽  
South Coast ◽  
Harbour Seal ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
The South ◽  
Breeding Sites ◽  
Harbour Seals

Grey seals (Halichoerus grypus Fabricius) and harbour seals (Phoca vitulina L.) have been surveyed on the coasts of Iceland since 1980. During the period 1980-2012, both seal species have declined markedly in numbers at the Icelandic coast. The grey seal has established a considerable breeding site on the northern spit of the Surtsey island. This is at present one of the biggest grey seal rookeries on the southern shores of Iceland, with estimated about 60 pups born there in the autumn of 2012. On the other hand, the harbour seal has not been numerous on Surtsey during breeding time in the summer. Breeding sites of harbour seals on the south coast of Iceland closest to Surtsey are in the estuaries of the glacial rivers Ölfusá, Þjórsá, Markarfljót and Kúðafljót. Harbour seals, however, haul-out in great numbers on the northern shores of Surtsey during the winter, presumably using the island as a resting place after foraging in the adjacent waters.

The seal louse, Echinophthirius horridus: an intermediate host of the seal heartworm, Dipetalonema spirocauda (Nematoda)

1981 ◽  
Vol 59 (7) ◽  
pp. 1457-1459 ◽  
Author(s):  
J. R. Geraci ◽  
J. F. Fortin ◽  
D. J. St. Aubin ◽  
B. D. Hicks
Keyword(s):  
New England ◽  
Intermediate Host ◽  
Developmental Stages ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
First Report ◽  
Harbour Seals

Heartworms, Dipetalonema spirocauda, are common in harbour seals, Phoca vitulina, that strand along the New England coast. Lice, Echinophthirius horridus, taken from a stranded harbour seal infected with seal heartworm carried three developmental stages of D. spirocauda. This is the first report of an intermediate host of the seal heartworm.

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.

The retina of the harbour seal, Phoca vitulina

1971 ◽  
Vol 49 (1) ◽  
pp. 19-23 ◽  
Author(s):  
G. S. Jamieson ◽  
H. D. Fisher
Keyword(s):  
Marine Mammals ◽  
Photoreceptor Cell ◽  
Outer Nuclear Layer ◽  
Cell Types ◽  
Phoca Vitulina ◽  
Inner Nuclear Layer ◽  
Horizontal Cells ◽  
Harp Seal ◽  
Harbour Seal ◽  
Retinal Layers

The structure of the retina of the harbour seal, Phoca vitulina richardii, is described. It is shown that the retina of the harbour seal is similar to that of the harp seal, in that it shows little zonation of the inner nuclear layer, possesses large horizontal cells, and has similar nuclear densities within the different retinal layers throughout the retina. The outer nuclear layer is also the thickest of all the retinal layers. Two types of photoreceptor cell, types B and C, were observed with a ratio of roughly 1:23 respectively. This ratio, along with a well-developed and extensive tapetum, indicates a highly light-sensitive retina. The existence of retinal folding in marine mammals is also questioned and discussed.

scholarly journals A note on the harbour seal (Phoca vitulina) in the Faroe Islands

2010 ◽  
Vol 8 ◽  
pp. 143 ◽  
Author(s):  
Bjarni Mikkelsen
Keyword(s):  
19Th Century ◽  
Anthropogenic Activities ◽  
Phoca Vitulina ◽  
The Other ◽  
Harbour Seal ◽  
Faroe Islands ◽  
Grey Seal ◽  
Historical Sources ◽  
Human Settlements ◽  
Harbour Seals

The harbour seal was exterminated as a breeding species in the Faroe Islands in the mid-19th Century. Historical sources document that the harbour seal used to be a common inhabitant of the sheltered fjords where breeding occurred. It was reported to be more common than the grey seal, the other pinniped specie resident around the Faroes. But the number of harbour seals seemingly decreased as human settlements and other anthropogenic activities increased. Seal hunting was apparently already introduced by the Norse that arrived on the islands in the 7th century, a hunt that finally lead to the extermination of the harbour seal. For the last 40 years the harbour seal has only been positively identified twice in the Faroe Islands, in 2001 and 2005.

Sign in / Sign up

Export Citation Format

Share Document