The
Shellfish Farm News
October 2003
Fall
rains bring nutrients
Shorter
days and longer nights are cooling the surface waters of
Baynes Sound down to a temperature of 10 C by the end of
October. This decrease in temperature from summer highs
of 18 to 20 C starts gradually and can change abruptly as
the ocean “turns over”. Temperatures can drop
several degrees overnight as cooling surface waters sink
and deeper cold water is brought to the surface. This can
be helped along by a south-east wind, typical of the fall
and winter storms in this area. All this water movement
brings nutrient rich waters to the surface where they are
exposed to sunlight and produce blooms of microscopic algae
(phytoplankton). Shellfish crops rely entirely on this rich
supply of natural food to plump up heading into the winter.
The
first heavy rains of the Fall typically arrive anytime between
mid-October and mid- November. They are characterized by
strong south-east winds and precipitation amounts that can
exceed 35-40 mm in a 24 hour period. There are generally
5 or 6 of these heavy storms that occur every Fall, interspersed
with the usual seasonal west coast drizzle. The storms discharge
large amounts of water on the mountains above Baynes Sound
that comes cascading down in torrents that fills the creek
beds to overflowing. All this freshwater does not harm the
oysters and clam crops but brings down more nutrients that
will feed the phytoplankton, upon which the shellfish depend.
As a
precautionary measure some areas of Baynes Sound are closed
to shellfish harvesting when the heavy rainfalls occur.
Samples of water and shellfish are taken daily from these
areas to confirm that the shellfish meet food safety standards
prior to re- opening. Residents of the Baynes Sound area
between Deep Bay and Courtenay play a vital role in continuing
to ensure that shellfish farms remain open by actively protecting
the quality of the water in the Sound. They do this by regularly
maintaining their septic systems, picking up their pet wastes
and disposing of waste oil and other household products
at approved recycling centres. Questions on the proper maintenance
of septic systems can be answered by one of the local Environmental
Health Officers at 336-3202.
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