An evaluation of environmental and other factors in some recent marine mammal mortalities in Europe: implications for conservation and management

1997 ◽  
Vol 5 (2) ◽  
pp. 89-98 ◽  
Author(s):  
M P Simmonds ◽  
S J Mayer
Keyword(s):  
North Sea ◽  
Marine Mammal ◽  
Sperm Whale ◽  
Striped Dolphin ◽  
The North ◽  
Phocine Distemper Virus ◽  
Dolphin Morbillivirus ◽  
The North Sea ◽  
Conservation And Management ◽  
Northeastern Atlantic

Major mortality events in marine mammal populations have become a feature of recent years and their causes have been much debated. Here we review the investigations that have been made to date into the 1988 seal epizootic in the North Sea region, the 1990-1992 striped dolphin epizootic in the Mediterranean Sea, and the recent spate of sperm whale strandings in the northeastern Atlantic. We consider the evidence for multifactorial causality in these events and the problems inherent in determining causes. The patterns of disease seen in both the phocine distemper virus and the dolphin morbillivirus precipitated events suggest complex underlying aetiologies with changes in hosts and (or) marine environment, with significant implications for the conservation and management of marine mammal populations. The sperm whale strandings are used to illustrate the difficulty of investigating or even detecting such events in marine mammal populations.

scholarly journals New sperm whale remains from the late Miocene of the North Sea and a revised family attribution for the small crown physeteroid Thalassocetus Abel, 1905

2021 ◽  
Author(s):  
Apolline ALFSEN ◽  
Mark BOSSELAERS ◽  
Olivier LAMBERT
Keyword(s):  
North Sea ◽  
Late Miocene ◽  
Sperm Whale ◽  
Close Relative ◽  
Sperm Whales ◽  
The North ◽  
The Family ◽  
The North Sea ◽  
Early Radiation ◽  
The One

In spite of a continuously expanding physeteroid fossil record, our understanding of the origin and early radiation of the two modern sperm whale families Kogiidae Gill, 1871 (including the pygmy and dwarf sperm whales, Kogia spp.) and Physeteridae Gray, 1821 (including the great sperm whale, Physeter Linnaeus, 1758) remains limited, especially due to the poorly resolved phylogenetic relationships of a number of extinct species. Among those, based on fragmentary cranial material from the late early to middle Miocene of Antwerp (Belgium, North Sea basin), the small-sized Thalassocetus antwerpiensis Abel, 1905 has been recognized for some time as the earliest branching kogiid. The discovery of a new diminutive physeteroid cranium from the late Miocene (Tortonian) of Antwerp leads to the description and comparison of a close relative of T. antwerpiensis. Thanks to the relatively young ontogenetic stage of this new specimen, the highly modified plate-like bones making the floor of its supracranial basin could be individually removed, a fact that greatly helped deciphering their identity and geometry. Close morphological similarities with T. antwerpiensis allow for the reassessment of several facial structures in the latter; the most important reinterpretation is the one of a crest-like structure, previously identified as a sagittal facial crest, typical for kogiids, and here revised as the left posterolateral wall of the supracranial basin, comprised of the left nasal (lost in kogiids for which the postnarial region is known) and the left maxilla. Implemented in a phylogenetic analysis, the new anatomical interpretations result in the new Belgian specimen and T. antwerpiensis being recovered as sister-groups in the family Physeteridae. Consequently, the geologically oldest kogiids are now dated from the Tortonian, further extending the ghost lineage separating these early late Miocene kogiid records from the estimated latest Oligocene to earliest Miocene divergence of kogiids and physeterids.

scholarly journals Beached bachelors: An extensive study on the largest recorded sperm whale Physeter macrocephalus mortality event in the North Sea

PLoS ONE ◽  
2018 ◽  
Vol 13 (8) ◽  
pp. e0201221 ◽  
Author(s):  
Lonneke L. IJsseldijk ◽  
Abbo van Neer ◽  
Rob Deaville ◽  
Lineke Begeman ◽  
Marco van de Bildt ◽  
...  
Keyword(s):  
North Sea ◽  
Sperm Whale ◽  
Extensive Study ◽  
Physeter Macrocephalus ◽  
Mortality Event ◽  
The North ◽  
The North Sea

scholarly journals Identification and real-time PCR quantification of Phocine distemper virus from two colonies of Scottish grey seals in 2002

2005 ◽  
Vol 86 (9) ◽  
pp. 2563-2567 ◽  
Author(s):  
John A. Hammond ◽  
Patrick P. Pomeroy ◽  
Ailsa J. Hall ◽  
Valerie J. Smith
Keyword(s):  
North Sea ◽  
Active Role ◽  
Phoca Vitulina ◽  
Primary Site ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
Acute Effects ◽  
The North ◽  
Phocine Distemper Virus ◽  
The North Sea

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.

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.

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