The Oysters of Chicopit: Status of the Oyster Population in Chicopit Bay before, during, and after the Construction of the Mile Point Project

Science Center Objects

Chicopit Bay, part of the Timucuan Ecological and Historic Preserve in Florida, is a small embayment at the intersection of San Pablo Creek (part of the Intercoastal Waterway) and the St. Johns River. Home to a number of small oyster beds, this area is now being dredged to help eliminate cross currents from the main shipping channel of the St. Johns. WARC researchers collect baseline environmental data to help assess the impact of this project on the oyster populations in the area.

Chicopit Bay, 2002

Chicopit Bay, 2002

The Science Issue and Relevance: Chicopit Bay, part of the Timucuan Ecological and Historic Preserve, is a small embayment at the intersection of San Pablo Creek (part of the Intercoastal Waterway) and the St. Johns River. Tidal flows from San Pablo Creek create cross currents in the main shipping channel of the St. Johns River, creating hazards to shipping. To eliminate these currents, the Army Corps of Engineers (ACE) will rework the channels. Dredging, spoil deposition, emplacement of rock training walls, and flow regime alteration will impact the numerous small oyster beds along the marsh fringe. Survival and recruitment of oysters is highly linked to salinity, period of immersion, current velocity, and depth of immersion. It is currently unknown in what way the physical changes to Chicopit Bay will affect the hydrology, and thus the oysters. The oysters in the Preserve are a major ecosystem engineer, providing habitat, stabilizing banks, and filtering water. Currently, the Preserve does not have a baseline of environmental conditions or oyster resources in order to assess the impact from the project. This study will establish baseline conditions, then monitor over a period of three years to determine the status of the oyster population. 

Methodology for Addressing the Issue: The oyster beds present in the bay prior to the ACE work will be mapped, and have ground stakes inserted, along with a nearby control site at Hannah Mills Creek. Once annually for the next two years, the sites will be remapped. Twice annually, counts, size, and status of oysters in random quadrats will be assessed for a sample of the beds present. Recruitment will be assessed using spat survey sticks emplaced and checked in spring and fall annually. Water quality will be assessed using continuously recording sondes in the bay and at the control site. Twice annually, high speed surface water mapping of the bay will be conducted.

Army Corps of Engineers planned changes to Chicopit Bay

Army Corps of Engineers' planned changes to Chicopit Bay

Future Steps: Results and interpretation from three years of baseline mapping, six oyster surveys, and six water surveys will be reported. If the ACE actions resulted in a detrimental effect on the ousters in the bay, the Preserve may require ACE to mitigate their actions, either through construction of habitat or flow alteration.