Transit time of digesta in captive harbour seals (Phoca vitulina)

1993 ◽  
Vol 71 (5) ◽  
pp. 1071-1073 ◽  
Author(s):  
Nina Hedlund Markussen
Keyword(s):  
Transit Time ◽  
Marine Mammals ◽  
Barium Sulphate ◽  
Stomach Content Analysis ◽  
Phoca Vitulina ◽  
Caloric Content ◽  
X Rays ◽  
Qualitative And Quantitative ◽  
Harbour Seals ◽  
Time Required

Stomach-content analysis can be used to identify the species and size of prey fishes eaten by marine mammals, and has been used for both qualitative and quantitative estimates of their food requirements. Methods that use mass or volume to determine the amount of fish eaten depend on the degree of digestion and the time required for the stomach to empty. The transit time of digesta was estimated by recording the initial defecation time and the time required for the stomach to empty in four harbour seals (Phoca vitulina). The seals were given meals varying in size from 0.5 to 2.1 kg and in caloric content from 4940 to 12 770 kJ/kg, and containing carmine or barium sulphate as a marker. The time from eating until red faeces were observed was between 2 h 35 min and 6 h 15 min. Also, barium sulphate was injected into the food given, and X-rays were used to estimate the time required for the stomach to empty. The stomach started to empty less than 1 h after the meal. Some prey remained in the stomach 5 h after eating.

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.

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.

scholarly journals Age determination methods in harbour seals (Phoca vitulina) with a review of methods applicable to carnivores

2010 ◽  
Vol 8 ◽  
pp. 245 ◽  
Author(s):  
Christina Lockyer ◽  
Beth Mackey ◽  
Fiona Read ◽  
Tero Härkönen ◽  
Ilk Hasselmeier
Keyword(s):  
Best Practices ◽  
Marine Mammals ◽  
Tooth Extraction ◽  
Age Determination ◽  
Detailed Examination ◽  
Phoca Vitulina ◽  
Growth Layer ◽  
Harbour Seals ◽  
Determination Methods ◽  
Layer Groups

The development of age determination methods in marine mammals is reviewed with particular reference to the use of teeth Growth Layer Groups (GLGs) formed in the dentine and cement of carnivores. Using this background, practices for sampling, tooth extraction and collection, storage and different methods of preparation of teeth as well as reading and counting GLGs are discussed and evaluated for the harbour seal (Phoca vitulina). The paper includes comments on best practices for counting GLGs with new examples from known-age seals, and also a detailed examination of confounding factors in interpreting GLGs such as mineralization anomalies and the phenomena of accessory lines, “false annuli” and “paired laminae” which have not been discussed previously. The paper concludes with recommendations for undertaking age estimation in harbour seals from sampling through final GLG interpretation with special emphasis on standardization of methods with other researchers.

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.

Regulation compliance by vessels and disturbance of harbour seals (Phoca vitulina)

2007 ◽  
Vol 85 (2) ◽  
pp. 290-294 ◽  
Author(s):  
Amber Johnson ◽  
Alejandro Acevedo-Gutiérrez
Keyword(s):  
Marine Mammals ◽  
Buffer Zone ◽  
Geographic Area ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Buffer Zones ◽  
Harbour Seals ◽  
The Us ◽  
Regulation Compliance

The US National Oceanic and Atmospheric Administration established a buffer zone around marine mammals to prevent harassment. The buffer zone varies by species listing status and by geographic area. However, it is unknown the extent to which vessels comply with these buffer zones. We selected harbor seals ( Phoca vitulina L., 1758) as a case study to describe compliance with the buffer zone. We conducted land-based observations from Yellow Island, Washington State, in a geographic area where the buffer zone is 91 m (100 yards), to estimate vessel distance from hauled-out seals and to evaluate seal response. We recorded 85.7% of kayaks, 57.1% of stopped powerboats, and 4.6% of passing powerboats violating the buffer zone. Seals were disturbed by kayaks and stopped powerboats at distances >91 m from the haul-out sites but not by moving powerboats ≤91 m from the sites. Hence, compliance of the buffer zone varied with vessel type and vessel activity. We suggest that a larger buffer zone for vessels lingering around the haul-out sites and enforcement of the buffer zone will minimize seal disturbance.

The influence of underwater data transmission sounds on the displacement behaviour of captive harbour seals (Phoca vitulina)

2006 ◽  
Vol 61 (1) ◽  
pp. 19-39 ◽  
Author(s):  
Ronald A. Kastelein ◽  
Sander van der Heul ◽  
Willem C. Verboom ◽  
Rob J.V. Triesscheijn ◽  
Nancy V. Jennings
Keyword(s):  
Data Transmission ◽  
Phoca Vitulina ◽  
Harbour Seals

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 Aerial low-frequency hearing in captive and free-ranging harbour seals (Phoca vitulina) measured using auditory brainstem responses

2016 ◽  
Vol 202 (12) ◽  
pp. 859-868 ◽  
Author(s):  
Klaus Lucke ◽  
Gordon D. Hastie ◽  
Kerstin Ternes ◽  
Bernie McConnell ◽  
Simon Moss ◽  
...  
Keyword(s):  
Low Frequency ◽  
Auditory Brainstem ◽  
Phoca Vitulina ◽  
Auditory Brainstem Responses ◽  
Harbour Seals ◽  
Free Ranging
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