Fatal Interspecies Mating Attempts of a Grey Seal (Halichoerus grypus) with Harbour Seals (Phoca vitulina) on the German North Sea Coast

2020 ◽  
Vol 174 ◽  
pp. 166
Author(s):  
K. Hülskötter ◽  
S. Rohner ◽  
S. Groß ◽  
J. Lakemeyer ◽  
M. Fähndrich ◽  
...  
1990 ◽  
Vol 102 (3) ◽  
pp. 299-309 ◽  
Author(s):  
U SCHUMACHER ◽  
H HORNY ◽  
G HEIDEMANN ◽  
W SCHULTZ ◽  
U WELSCH

2015 ◽  
Vol 13 ◽  
pp. 41-43
Author(s):  
Erlingur Hauksson

Grey seals (Halichoerus grypus Fabricius) and harbour seals (Phoca vitulina L.) have been surveyed on the coasts of Iceland since 1980. During the period 1980-2012, both seal species have declined markedly in numbers at the Icelandic coast. The grey seal has established a considerable breeding site on the northern spit of the Surtsey island. This is at present one of the biggest grey seal rookeries on the southern shores of Iceland, with estimated about 60 pups born there in the autumn of 2012. On the other hand, the harbour seal has not been numerous on Surtsey during breeding time in the summer. Breeding sites of harbour seals on the south coast of Iceland closest to Surtsey are in the estuaries of the glacial rivers Ölfusá, Þjórsá, Markarfljót and Kúðafljót. Harbour seals, however, haul-out in great numbers on the northern shores of Surtsey during the winter, presumably using the island as a resting place after foraging in the adjacent waters.


Author(s):  
Bernie McConnell

SynopsisGrey seals (Halichoerus grypus) and common seals (Phoca vitulina) both occur in Orcadian waters. In previous centuries they formed an important resource for both domestic use and export.Annual grey seal pup production has more than doubled since 1964. Productivity on individual islands is influenced by human activity. Total population size is estimated to have risen from around 10,000 in 1964 to around 20,000 in 1982 despite a management policy of culling originally intended to stop population growth. Grey seals tagged in Orkney have been recovered around most parts of the North Sea, Norway, the Faeroes and south to Ireland.Considerably less is known about the biology of common seals in Orkney. A boat survey in 1979 counted 2653 adults and 420 pups.


1977 ◽  
Vol 41 (1) ◽  
pp. 99-106 ◽  
Author(s):  
H. E. Drescher ◽  
U. Harms ◽  
E. Huschenbeth

2005 ◽  
Vol 86 (9) ◽  
pp. 2563-2567 ◽  
Author(s):  
John A. Hammond ◽  
Patrick P. Pomeroy ◽  
Ailsa J. Hall ◽  
Valerie J. Smith

The North Sea European harbour seal (Phoca vitulina) population has endured two phocine distemper virus (PDV) epidemics in 1988 and 2002. The grey seal (Halichoerus grypus) is a sympatric seal species that shows little or no mortality from PDV. Two Scottish grey seal breeding colonies were sampled for evidence of PDV infection approximately 2 months after the peak of the 2002 epidemic. In both colonies, a proportion of mothers (13/109) and pups (6/84) tested positive for PDV in their leukocytes. All infected animals were asymptomatic and completed the breeding season successfully. These results illustrate that grey seals come into contact with infectious seals and can become infected themselves without experiencing acute effects. In some seals the virus is able to replicate from the primary site of infection. This study provides evidence that grey seals may have an active role in the spread of PDV during an epidemic.


1990 ◽  
Vol 47 (6) ◽  
pp. 1223-1227 ◽  
Author(s):  
Morten Ryg ◽  
Christian Lydersen ◽  
Nina H. Markussen ◽  
Thomas G. Smith ◽  
Nils Are Øritsland

We have investigated the relationships between percent blubber content and xiphostemal blubber thickness or girth-to-length ratios in ringed seal (Phoca hispida), harp seal (Phoca groeniandica), and grey seal (Halichoerus grypus). The blubber content was significantly correlated with blubber depths and girth-to-length ratios in all three species, in addition, we have developed an estimator for percent blubber content (the LMD-index) based on standard length (L, in meters), body mass (M, in kilograms), and on blubber thickness (d, in meters) measured at a defined position dorsally. From these variables the percent blubber content (B%) can be estimated by the expression B% = 4.44 + 5693 [Formula: see text], with a standard error of the estimate of three percentage units. This index also gave reasonable estimates for blubber content in three harbour seals (Phoca vitulina) and eight bearded seals (Erignatus harbatus).


1983 ◽  
Vol 40 (3) ◽  
pp. 267-271 ◽  
Author(s):  
Paul Brodie ◽  
Brian Beck

The increase in population size of the grey seal (Halichoerus grypus) off eastern Canada over the past 20 yr may be attributed to a decrease in shark stocks, their supposed predators. Reduction of the shark population is presumed to have resulted from a directed longline fishery and, of greater significance, from a change in the fishery for swordfish (Xiphias gladius) from selective harpooning to pelagic longlining, which has produced a large bycatch of sharks. The resulting enhanced survival of grey seals is reflected in greater infestation of commercially important fish species by the codworm (Phocanema decipiens).Key words: grey seals, harbour seals, sharks, swordfish, codworm, predation, fisheries


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