scholarly journals Fish preference by the harbour seal (Phoca vitulina), with implications for the control of damage to fishing gear

2001 ◽  
Vol 58 (4) ◽  
pp. 824-829 ◽  
Author(s):  
S Lunneryd
Keyword(s):  
Phoca Vitulina ◽  
Harbour Seal ◽  
Fishing Gear

scholarly journals Historical trend in harbour seal (Phoca vitulina) abundance in Iceland back to the year 1912

2010 ◽  
Vol 8 ◽  
pp. 147 ◽  
Author(s):  
Erlingur Hauksson ◽  
Sólmundur T Einarsson
Keyword(s):  
Population Decline ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Early 20Th Century ◽  
Fishing Gear ◽  
Early 19Th Century ◽  
Harvest Rate ◽  
Aerial Surveys ◽  
Seal Population ◽  
By Catch

The harbour seal (Phoca vitulina) is Iceland’s most abundant seal and has likely been exploited since the settlement of the country. Detailed information on skin exports is available as far back as 1912, and suggests that the catch, consisting mainly of pups, was far higher in the early 20th century than now. Assuming that skin exports were proportional to catches, these data were used to back-calculate the size of the Icelandic harbour seal population to the year 1912. The results indicate that the harbour seal population was considerably larger in the early 19th century than at present, about 60,000 (90% CI:40-100) animals. Aerial surveys conducted since 1980 indicate that the population has declined from 33,000 (90% CI:26,000-44,000) animals in 1980 to about 12,000 (90% CI:9,000-16,000) animals in 2006. The population time series suggests thatthe stock began to decline rapidly around 1960 and continued to decrease until 2003. In the period 1980 - 2003, the population declined even though reported catches were relatively low. Harvest rate had probably been about 10% before 1960. Between 1960 and 1980 the reported harvest rate increased to about 13%, but unknown numbers of adult seals were also taken as by-catch and shot in defence of salmon rivers. Since 2003, total removals have decreased and the population decline appears to have ceased. Entanglements in fishing gear and other incidental unreported hunting could increase again in the future. Therefore, the population must be monitored on a regular basis, and better information on by-catch and other unreported harvest is needed.

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.

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