scholarly journals Saccadic movement strategy in a semiaquatic species – the harbour seal (Phoca vitulina)

2017 ◽  
Vol 220 (8) ◽  
pp. 1503-1508 ◽  
Author(s):  
Bart R. H. Geurten ◽  
Benedikt Niesterok ◽  
Guido Dehnhardt ◽  
Frederike D. Hanke
Keyword(s):  
Phoca Vitulina ◽  
Harbour Seal ◽  
Saccadic Movement ◽  
Movement Strategy

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 Trace metal accumulation in hair and skin of the harbour seal, Phoca vitulina

1993 ◽  
Vol 26 (3) ◽  
pp. 152-155 ◽  
Author(s):  
C. Wenzel ◽  
D. Adelung ◽  
H. Kruse ◽  
O. Wassermann
Keyword(s):  
Trace Metal ◽  
Metal Accumulation ◽  
Phoca Vitulina ◽  
Harbour Seal

scholarly journals Deiminated proteins and extracellular vesicles as novel biomarkers in pinnipeds: Grey seal (Halichoerus gryptus) and harbour seal (Phoca vitulina)

Biochimie ◽  
2020 ◽  
Vol 171-172 ◽  
pp. 79-90 ◽  
Author(s):  
Bergljót Magnadóttir ◽  
Pinar Uysal-Onganer ◽  
Igor Kraev ◽  
Vilhjálmur Svansson ◽  
Karl Skírnisson ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Grey Seal ◽  
Novel Biomarkers

Repetition enhances hearing detection thresholds in a harbour seal (Phoca vitulina)

1993 ◽  
Vol 71 (5) ◽  
pp. 926-932 ◽  
Author(s):  
S. D. Turnbull ◽  
J. M. Terhune
Keyword(s):  
White Noise ◽  
Background Noise ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Detection Thresholds ◽  
Noise Masking ◽  
Phoca Groenlandica ◽  
Hearing Thresholds ◽  
Lower Detection ◽  
Pinniped Species

Pure-tone hearing thresholds of a harbour seal (Phoca vitulina) were measured in air and underwater using behavioural psychophysical techniques. A 50-ms sinusoidal pulse was presented in both white-noise masked and unmasked situations at pulse repetition rates of 1, 2, 4, and 10/s. Test frequencies were 0.5, 1.0, 2.0, 4.0, and 8.0 kHz in air and 2.0, 4.0, 8.0, and 16.0 kHz underwater. Relative to 1 pulse/s, mean threshold shifts were −1, −3, and −5 dB at 2, 4, and 10 pulses/s, respectively. The threshold shifts from 1 to 10 pulses/s were significant (F = 12.457, df = 2,36, p < 0.001) and there was no difference in the threshold shifts between the masked and unmasked situations (F = 2.585; df = 1,50; p > 0.10). Broadband masking caused by meteorological or industrial sources will closely resemble the white-noise situation. At high calling rates, the numerous overlapping calls of some species (e.g., harp seal, Phoca groenlandica) present virtually continous "background noise" which also resembles the broadband white-noise masking situation. An implication of lower detection thresholds is that if a seal regularly repeats short vocalizations, the communication range of that call could be increased significantly (80% at 10 pulses/s). This could have important implications during the breeding season should storms or shipping noises occur or when some pinniped species become increasingly vocal and the background noise of conspecifics increases.

Masked and unmasked pure tone detection thresholds of a harbour seal listening in air

1991 ◽  
Vol 69 (8) ◽  
pp. 2059-2066 ◽  
Author(s):  
J. M. Terhune
Keyword(s):  
White Noise ◽  
Pure Tone ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Optimal Conditions ◽  
Vascular Changes ◽  
Detection Thresholds ◽  
Noise Masker ◽  
Auditory Systems ◽  
Tone Detection

In-air pure tone detection thresholds of a harbour seal (Phoca vitulina) were measured using behavioural psychophysical techniques. Thresholds dropped from about 70 dB re 20 μPa at 0.1 kHz to about 35 dB re 20 μ Pa at 4 kHz and then increased to about 45 dB re 20 μPa at 16 kHz. Increased sensitivities at 2 and 8 kHz, which have been reported in other pinnipeds, were not evident. In-air intensity detection thresholds averaged 32 dB above their underwater counterparts (1–16 kHz). Masking studies found the critical ratios at 0.25, 0.5, and 1 kHz to be 24, 15, and 21 dB, respectively (white noise masker). From 0.2 to 1.5 kHz, bandwidths 20 dB below the level of pure tone maskers were 0.16–0.18 kHz. Circumstantial evidence suggests the possibility that blood vascular changes associated with diving might also influence the sensitivity of the auditory systems of seals. Under optimal conditions, a pup's airborne cries may be detected by its mother at ranges of 1 km or more.

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.

Experiments with the Harbour Seal, Phoca vitulina, a Definitive Host of a Marine Nematode, Porrocaecum decipiens

1953 ◽  
Vol 10 (8) ◽  
pp. 539-547 ◽  
Author(s):  
D. M. Scott
Keyword(s):  
Definitive Host ◽  
Atlantic Cod ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Osmerus Mordax ◽  
Marine Nematode ◽  
The Third ◽  
Males And Females ◽  
Distinct Increase ◽  
Hippoglossoides Platessoides

Infestation experiments carried out in 1947 and 1948 showed that the harbour seal (Phoca vitulina) was a definitive host of a larval nematode found in the flesh of the Atlantic cod (Gadus callarias), smelt (Osmerus mordax), Canadian plaice (Hippoglossoides platessoides) and eelpout (Macrozoarces americanus). Adult worms recovered from experimentally infested seals were identified as Porrocaecum decipiens. Some larval Porrocaecum in the four species of fishes studied were P. decipiens.The worms lost their larval characteristics by moulting between the third and sixth day following introduction into the seal. Sexual maturation proceeded rapidly after the eleventh day and some males and females matured before the twentieth day. Maturation was accompanied by a distinct increase in size.

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