scholarly journals Harbour seals (Phoca vitulina) and rehabilitation

2010 ◽  
Vol 8 ◽  
pp. 355 ◽  
Author(s):  
Nynke Osinga ◽  
Pieter ‘t Hart
Keyword(s):  
Social Support ◽  
Anthropogenic Impact ◽  
Wadden Sea ◽  
Quality Standards ◽  
Phoca Vitulina ◽  
The Past ◽  
Harbour Seals ◽  
Seal Population ◽  
One Year ◽  
Ecosystem Changes

Throughout the past few decades, rehabilitation of seals has become an activity that is anchored in the present day society of many countries. Seals are primarily rehabilitated to help individual animals in distress. At the same time, the release of seals which would have otherwise died can be considered as a contribution to the population. Most rehabilitated seals are animals under one year of age. They are mainly orphans, weaned seals with complications and seals with a parasiticbronchopneumonia. For the optimal handling of seals and their diseases, centralised operations with quality standards are essential. Rehabilitation provides an instrument to monitor the health of the seal population and its ecosystem. Changes in stranding trends or the appearance of new diseases can be monitored. Moreover, rehabilitation is important to show the general public thestate of the marine environment. In the Netherlands there is significant social support for the rehabilitation of seals. Experience obtained with seal care is of importance in countries where urgent help of threatened seal species is required. Here individual seals are also ambassadors to raise support for the protection of this species in general. Given that the anthropogenic impact on the seals and their environment is extensive in the Wadden Sea, rehabilitation centres can compensate the consequences of this impact on individual seals as well as the population as a whole.

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 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

Abundance and maturity of three species of parasitic anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) occurring in Sable Island harbour seals (Phoca vitulina)

2002 ◽  
Vol 80 (3) ◽  
pp. 442-449 ◽  
Author(s):  
Wayne T Stobo ◽  
L Paul Fanning ◽  
Brian Beck ◽  
G Mark Fowler
Keyword(s):  
Prey Species ◽  
Phoca Vitulina ◽  
Final Host ◽  
Anisakis Simplex ◽  
Halichoerus Grypus ◽  
Commercial Fish ◽  
Pseudoterranova Decipiens ◽  
Harbour Seals ◽  
Seal Population ◽  
Contracaecum Osculatum

Three species of anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) co-occur in the stomachs of Sable Island harbour seals (Phoca vitulina). The sealworm, P. decipiens, was the commonest nematode in these seals. Anisakis simplex was found in much smaller numbers, none mature, indicating that the harbour seal is not a true final host to this parasite. Contracaecum osculatum was rare but half were mature. Pseudoterranova decipiens increased in abundance with size of the seal. An inverse relationship was observed between P. decipiens abundance and the age of seals of similar size, probably owing to changes in diet. Numbers of P. decipiens may have declined over the summer, coincident with an increase in the proportion of mature worms in the stomach. From similarities between the worm infections of grey seals (Halichoerus grypus) and harbour seals, we infer that A. simplex abundance may also exhibit a decline in abundance. Contracaecum osculatum was only encountered during the latter half of the year, suggesting an association with prey species of corresponding periodicity in their distribution. We estimate that the abundance of sealworm in harbour seals is about 2.5% of that carried by the grey seal population. This could imply that harbour seals represent an insignificant vector of the sealworm infecting commercial fish species in the Northwest Atlantic, provided density-dependent relationships exist between worm abundances in different host species.

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.

Observations on a Colony of Whelping Harbour Seals, Phoca vitulina concolor, on Sable Island, Nova Scotia

1971 ◽  
Vol 28 (5) ◽  
pp. 755-759 ◽  
Author(s):  
Jean Boulva
Keyword(s):  
Nova Scotia ◽  
Phoca Vitulina ◽  
Harbour Seals ◽  
Seal Population ◽  
Males And Females

Three censuses indicated that approximately 1220 harbour seals were at Sable Island at the beginning of whelping in 1970. About 270 pups were born, representing 18% of the total seal population after whelping. Maximum whelping occurred during the last week of May. Males represented 52% of the 118 pups examined. At least 12% of the pups died in the 1st month of life. Pups born with lanugo represented 16% of all pups born. Males and females averaged 80 cm long and 11 kg in weight at birth; 3 weeks later, the males averaged 91 cm and 24 kg and the females 86 cm and 20 kg.

Diving patterns of harbour seals (Phoca vitulina) in the Wadden Sea, the Netherlands and Germany, as indicated by VHF telemetry

1997 ◽  
Vol 75 (12) ◽  
pp. 2063-2068 ◽  
Author(s):  
Edith H. Ries ◽  
Petra Paffen ◽  
Ilona M. Traut ◽  
Paul W. Goedhart
Keyword(s):  
The Netherlands ◽  
Body Length ◽  
Air Temperature ◽  
Adult Male ◽  
Wadden Sea ◽  
Ambient Air ◽  
Phoca Vitulina ◽  
Late Autumn ◽  
Dive Behaviour ◽  
Harbour Seals

The diving behaviour of 25 harbour seals, Phoca vitulina (14 females and 11 males), of various body lengths was monitored by means of VHF telemetry at different locations in the Wadden Sea during late autumn in 1991 and 1992. Median dive durations for individual seals ranged from 46 s to 2.9 min. The maximum dive recorded was 31 min, performed by an adult male, which represents the longest dive reported for harbour seals. Dive endurance increased significantly in relation to body length. Female harbour seals tended to perform fewer short dives and had a more narrow distribution of dive times. We detected no diurnal differences in dive behaviour and only the ambient air temperature was found to influence the duration of surface periods, in that surface intervals tended to be shorter when temperatures were below 9 °C. The overall mean percentage of dive time was 85%, with individuals varying from 76 to 93%, and was in general higher in females.

scholarly journals Monitoring trends in the abundance of harbour seals (Phoca vitulina) in Icelandic waters

2010 ◽  
Vol 8 ◽  
pp. 227 ◽  
Author(s):  
Erlingur Hauksson
Keyword(s):  
Coastal Area ◽  
East Coast ◽  
Aerial Survey ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Northwest Coast ◽  
Coastal Regions ◽  
Harbour Seals ◽  
Seal Population ◽  
Icelandic Waters

Harbour seal (Phoca vitulina) numbers along the coast of Iceland were monitored by aerial survey in the period 1980-2006. Trends in the abundance of the harbour seal population on the whole coast and in coastal regions of Iceland waters were estimated using ANCOVA on the survey counts, corrected for the influence of several covariates. Harbour seals were found in every coastal area, but were most abundant in Faxaflói, Breiðafjörður and on the northwest coast inthe beginning of this study. Harbour seal numbers declined significantly at a rate of rest = -0.04 (SE 0.005) yr-1 during this period. Decline was highest in Faxaflói and at the south coast (≅7%), while the east coast experienced a significant but lesser (≅1%) decline. Other coastal areas did not show significant trends. The northwest coast was the richest harbour seal area in Iceland in 2006. In Icelandic waters seals are commercially harvested, and unreported but probably high numbers of harbour seals are killed intentionally by shooting and accidentally in fishing geareach year. These factors likely contributed to the overall observed decline in seal numbers.

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