The
opening of oyster season in the Calcasieu Lake public oyster
area is fast approaching. The West Cove Conditional Management
Area (west side of Calcasieu ship channel) will open one-half
hour before sunrise on Oct. 15, 2007, and will close one-half
hour after sunset on April 30, 2008. The Calcasieu Lake
Conditional Management Area (east side of Calcasieu ship
channel) will open one-half hour before sunrise on Nov.
1, 2007, and will close one-half hour after sunset on April
30, 2008. The sack limit for Calcasieu Lake is set at 15
one-and-one-half bushel sacks per day as provided for in
R.S. 56:435.1.1. However, these conservation actions will
not supercede public health closures.
The
reason for health closures is the occurrence of high fecal
coliform counts during high flow episodes of the Calcasieu
River. Fecal coliform is a bacterium found in the intestines
of warm blooded animals – birds and mammals, including
humans. Fecal coliform is monitored as an indicator species.
It is assumed that if it is present, other human pathogens
and bacterium such as hepatitis, vibrio, cholera, etc. may
also be present.
Fecal
coliform bacteria can live for up to 48 hours outside of
the gut of warm blooded animals. When river flows are heavy,
water carrying fecal coliform and potentially other pathogens
reaches the harvest area alive. A study completed in the
early 1990s by the Louisiana Department of Public Health
correlated fecal coliform counts on Calcasieu Lake and West
Cove oyster harvest areas with the Calcasieu River stage
at Kinder. When the river stage at Kinder reaches 13.5 feet,
fecal coliform numbers on the Lower Calcasieu management
area pose a health threat. A health threat is posed for
the West Cove management area when the Kinder station reaches
seven feet. Harvesters monitoring the status of openings
can call (800) 256-2775.
The
mechanism by which fecal coliform enters our waterways is
through runoff during heavy rainfall. This is called non-point
source pollution, which is very diffuse and hard to identify.
The concern over fecal coliform in our waterways can be
divided into two sources; those coming from human activities,
and naturally occurring sources (birds and animals). During
winter months, water draining through marshes surrounding
Calcasieu Lake picks up fecal coliform from large waterfowl
populations overwintering and from furbearers and other
animals. Normally, these wastes are assimilated in the marsh
ecosystem and reduced to usable nutrients and organic matter.
But, in heavy rain and in cooler seasons, it is flushed
out before being metabolized or reduced.
Runoff
from rural and urban areas picks up fecal coliform from
faulty or overloaded sewer treatment systems. Both residential
and municipal sewer treatment plants are designed to reduce
sewage and bacteria through biological and mechanical treatment.
But heavy rainfall runoff overloads the systems and water
flushes untreated waste out and eventually into the river.
Improperly maintained home sewage treatment units also contribute
to untreated waste entering the river.
Oysters
are filter feeders and readily pick up bacteria and pathogens
when actively feeding. The major concern with oysters is
caused by the raw consumption of oysters and thereby increasing
the risk of also consuming live bacteria and pathogens.
According
to the U.S. Food and Drug Administration, approximately
20 million Americans eat raw oysters; however the risk is
not the same for everyone. People with certain health conditions
such as diabetes, immune disorders, stomach problems, liver
disorders or disease and those on long-term steroid use
have an increased risk of becoming ill from eating raw oysters.
People within these categories or those wanting to reduce
their risk and still enjoy oysters are encouraged to consume
only fully cooked oysters.
Back
to Main |
