Indigenous Oyster Habitat Project
by: Bud Abbott
Background: In July 2006 an oyster cultch donated by Drakes Bay
Oyster Company was loaded onto skiffs by volunteers and set in place by
other volunteers standing in water at the site of the Marin Rod and Gun
Club. The reefs were positioned at three depths:
-1.5, -2.5 and -4 feet in depth, mean lower low water (MLLW). The layout
of the reefs relative to the shore line and the recreational angling
pier are shown in the figures below.
Approximately 27-cubic yards of cultch was use to make the three reef rows.
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Each row had three sections: * 25-feet
with bags stacked pyramid style, three layers high
* 25-feet long with bags stacked Lincoln log style, stacked three
layers high
* 25-feet long with the shells not bagged but scattered in a mound on
the mud.
* Between each section there was a space 5-feet wide termed a surge
channel.
(See diagram below)
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Then in June 2007, 26-reef mounds were
constructed in water approximately -2-ft. MLLW. The mounds are in four
staggered rows approximately 3 meter apart. Each mound consists of 30 to
35 bags of shells. The mounds are intended to approximate the ecological
functionality of a coral head or a constructed reef ball. The mounds are
approximately 2 feet high off the bottom and held in place by five-foot
long 4-rebar anchors bent into an "L" and driven approximately 3-feet
into the soft mud.
The reef mound project resulted in the
construction of the largest artificial reef ever built in San Francisco
Bay. Monitoring over the next year is necessary to document the success
of the project but it is anticipated that it will support nearly
250,000-500,000 native oysters.
... Bud Abbott
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