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Gaspereau deaths
on the Petitcodiac River
June 2003
By Léa Oslen
Users
of the biking and walking trail along the Petitcodiac River,
as well as homeowners on the riverfront probably found it hard
to stay oblivious to the sight – and smell – of
hundreds of dead gaspereaus washing up along the river’s
muddy banks during the last two weeks this past June.
The
gaspereau (a common term for alewife and blueback herring) is
both an anadromous or landlocked fish. Anadromous means it lives
most of its life in the sea, but migrates annually into rivers
to spawn. Landlocked gaspereau lives in lakes, such as the Great
Lakes. In New Brunswick, the gaspereau is common in rivers such
as the Saint John, Miramichi and Petitcodiac where it migrates
in May and June from the Bay of Fundy.
 Gaspereau
mortality as a result of spawning is common and usually high (40
to 60 %) which explains the large number of fishs that annually
wash-up on the banks of the rivers they migrate into. This past
June, massive wash-ups on the Saint John River attracted media
attention and also prompted an investigation. The culprit, aside
from natural causes was determined to be the unusually cool temperatures
of the river’s water coupled with a fungus infection which
revealed to be lethal in these circumstances ..
In
the Petitcodiac River, the numbers of gaspereaus washing-up were
slightly higher than other years. Other than natural causes, this
could be a result of gate operations on the causeway which dams
the river. The Department of Fisheries and Oceans (DFO) is investigating
the matter; results will be posted on our web site.
Additional
information on the Gaspereau can be found on the Riverkeeper’s
site at:
www.riverkeeper.org/english/The_Petitcodiac/Species/alewife.htm
or on the DFO web site at:
http://www.dfo-mpo.gc.ca/zone/under-sous_e.htm
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