Saturday, January 22, 2011

UNDIAGNOSED DIE-OFF, SEAL - CANADA (02): (NEWFOUNDLAND AND LABRADOR)

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Date: 19 Jan 2010
From: Lena Measures



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>

--
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



[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

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