UNDIAGNOSED DIE-OFF, SEAL - CANADA (02): (NEWFOUNDLAND AND LABRADOR)
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Date: 19 Jan 2010
From: Lena Measures
<Lena.Measures@dfo-mpo.gc.ca>
Regarding "Undiagnosed die-off, seal - Canada: (NL) 20110118.0207,"
here is some information to date.
There are dead, apparently premature, harp seal pups and adults (_Phoca groenlandica_) on shore over a wide geographic area including the St. Lawrence Estuary but mostly off northern Newfoundland and Labrador. Confirmed numbers dead are in the low hundreds so far and involve mostly adult animals. Reports of early pupping began around Christmas. Strong storm surges in early January 2011 have brought some carcasses ashore.
Harp seals migrate down from the arctic in late fall to eventually give birth and breed on the Front (off eastern Newfoundland and
Labrador) and Gulf of St. Lawrence in late winter. The normal period for harp seal parturition is end of February, early March. It is natural for some harp seal pups to be born premature even in January.
The harp seal population is estimated at 8 to 9 million animals with natural mortality estimated at 4 percent.
Mortality of pups in their 1st year of life is estimated at 20 - 30 percent, declining with age. Pups are nursed for about 12 days then abandoned, after which they fast and moult on the ice as it ice drifts into the North Atlantic in early spring (April/May). As the ice melts pups swim and begin to hunt on their own, eventually moving northwards. After abandoning their pups females mate and adults rest on the ice to moult and eventually migrate north. Harp seals spend about 6 months in arctic waters and 6 months off southeastern Canadian Atlantic waters.
Observed mortalities may be unusual but expected due to poor to absent ice conditions and the size of the herd. We are examining carcasses and differentials include environmental change, poaching and an epizootic. Adults appear in good body condition. Phocine distemper virus or PDV (morbillivirus) is enzootic in this population and while epizootics have killed thousands of seals in Europe, epizootics have not been observed in Canadian waters perhaps due to herd immunity (83 percent of examined harp seals are seropositive to PDV). Necropsies and further investigations are in progress in collaboration with fisheries agents and veterinary pathologists at provincial and university laboratories including the Canadian Co-operative Wildlife Health Center.
Ice conditions can be monitored at the Canadian Ice Service website:
http://ice-glaces.ec.gc.ca/prods/WIS57CT/20110117180000_WIS57CT_0005506610.pdf>
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Communicated by:
Dr. Lena Measures
Marine mammal health
Fisheries and Oceans Canada
Maurice Lamontagne Institute
850 route de la mer, Mont-Joli, Qc, Canada G5H 3Z4 <Lena.Measures@dfo-mpo.gc.ca> <http://www.dfo-mpo.gc.ca/science/coe-cde/cemam/index-eng.html>
[We appreciate Dr. Measures taking time to inform us and look forward to a follow up report regarding this condition in the seals. - Mod.TG]
[see also:
Undiagnosed die-off, seal - Canada: (NL) 20110118.0207] .....................tg/ejp/dk/ll
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