scholarly journals Parasites in harbour seals (Phoca vitulina) from the German Wadden Sea between two Phocine Distemper Virus epidemics

2007 ◽  
Vol 61 (4) ◽  
pp. 239-245 ◽  
Author(s):  
K. Lehnert ◽  
J. A. Raga ◽  
U. Siebert
Keyword(s):  
Wadden Sea ◽  
Phoca Vitulina ◽  
Phocine Distemper Virus ◽  
Harbour Seals

scholarly journals Movements and site fidelity of harbour seals (Phoca vitulina) in Kattegat, Denmark, with implications for the epidemiology of the phocine distemper virus

2012 ◽  
Vol 70 (1) ◽  
pp. 186-195 ◽  
Author(s):  
Rune Dietz ◽  
Jonas Teilmann ◽  
Signe M. Andersen ◽  
Frank Rigét ◽  
Morten T. Olsen
Keyword(s):  
Gene Flow ◽  
Home Range ◽  
West Coast ◽  
Site Fidelity ◽  
Phoca Vitulina ◽  
Swedish West Coast ◽  
Phocine Distemper Virus ◽  
Harbour Seals ◽  
Limited Gene Flow ◽  
Satellite Tagging

Abstract Dietz, R., Teilmann, J., Andersen S. M. Rigét, F., and Olsen, M. T. 2013. Movements and site fidelity of harbour seals (Phoca vitulina) in Kattegat, Denmark, with implications for the epidemiology of the phocine distemper virus. – ICES Journal of Marine Science, 70:186–195. Twenty-seven harbour seals were caught and tagged at the island of Anholt in central Kattegat, Denmark, the epicentre of the phocine distemper virus (PDV) outbreaks in 1988 and 2002 that killed 50–60% of the populations. The satellite tagging shows that harbour seals from Anholt moved widely across Kattegat with a maximum distance of 249 km from the tagging haul-out site. Overall, females travelled over a wider area compared with males [90% kernel home range (KHR) females, 5189 km2; males, 3293 km2). KHR calculated for yearlings (6414 km2) is larger than for subadults (2534 km2), which again is larger than for adult seals (1713 km2), showing a strong site fidelity, indicating limited gene flow between haul-out sites. Distances moved and home range sizes increased across autumn, peaked in February–March, and decreased through spring. During the breeding season in spring, all seals were very stationary around Anholt. The onset of the PDV epizootics in 1988 and 2002 took place when the Anholt harbour seals congregate on the Island during April. Anholt seal were also documented to have contact with infected seal locations at Hesselø, Læsø, and the Swedish west coast, although this contact takes place during winter prior to the documented summer outbreaks.

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

scholarly journals Status of harbour seals (Phoca vitulina) in mainland Norway

2010 ◽  
Vol 8 ◽  
pp. 61 ◽  
Author(s):  
Kjell Tormod Nilssen ◽  
Nils-Erik Skavberg ◽  
Michael Poltermann ◽  
Tore Haug ◽  
Tero Härkönen ◽  
...  
Keyword(s):  
Tidal Cycle ◽  
Lower Estimate ◽  
Phoca Vitulina ◽  
Aerial Photo ◽  
Norwegian Coast ◽  
Phocine Distemper Virus ◽  
Harbour Seals ◽  
Minimum Estimate ◽  
Almost All

Harbour seals were counted along the entire Norwegian coast at known moulting haulout sites in the period mid-August to early September 2003-2006. In 2003-2005, almost all known moulting areas from Finnmark to Vestfold counties were covered by aerial photo surveys flown at altitudes of approximately 800-900 ft (243-274m), and at low tide (± 2 hours). Surveys in the Østfold County were flown in 2003-2006 at 300 ft (91m), and the small tidal amplitudes permitted counts to be carried out irrespective of the tidal cycle. In some sub-areas, two or three independent surveys were conducted. Visual counts using binoculars from smaller boats and islands were carried out in some selected areas. The surveys revealed a total minimum population of 6,705 harbour seals in Norwegian waters. Harbour seals were most abundant in the Nordland and Sør-Trøndelag counties with minimum estimates of approximately 2,500 and 1,500 seals, respectively. The presented minimum estimate is approximately 800 seals lower than an estimate obtained in a comparable study carried out during the moult in 1996-1999. Increased anthropogenic removals, and the phocine distemper virus (PDV) epidemic in the Skagerrak region in 2002, may have contributed to the current lower estimate.

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.

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 Predicting recurrent PDV epizootics in European harbour seals (Phoca vitulina)

2010 ◽  
Vol 8 ◽  
pp. 275 ◽  
Author(s):  
Tero Härkönen ◽  
Karin C Harding
Keyword(s):  
North Sea ◽  
Herd Immunity ◽  
Phoca Vitulina ◽  
High Rate ◽  
The North ◽  
Rate Of Spread ◽  
Phocine Distemper Virus ◽  
Harbour Seals ◽  
The North Sea ◽  
Sea Area

Phocine Distemper Virus (PDV) caused mass mortality in European harbour seals (Phoca vitulina) in 1988 and in 2002. Both epizootics likely originated from refugia in Arctic seals, where data indicate PDV hops among populations and species. The metapopulation structure of host populations is suggested to be the reason why PDV is preserved among Arctic seals, since the high rate of spread of PDV would require much larger panmictic populations to maintain an infection. The pattern of sudden outbreaks of PDVis also seen in grey seals (Halichoerus grypus), the only to date identified species that could act as a vector between Arctic and North Sea seal populations. Harbour seal populations along mainland Europe were below critical herd immunity levels by 3-5 years after the events, and thus vulnerable for new outbreaks, but historical data and the 14 years between the 2 epizootics suggest that harbour seals in the North Sea area are only rarely exposed to the infective agent. The risk for new outbreaks of the seal plague in North Sea harbour seals is likely linked to the dynamics of the disease in Arctic seal species as well asvector species.

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.

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