Website

https://doi.org/10.2983/035.037.0514

Region(s)

NW

Summary

The eastern oyster Crassostrea virginica is an important component of the ecology of Apalachicola Bay, Florida, and the economy of the region. Although oyster reefs in the Bay occur in both tidal zones, subtidal reefs have received the most attention because they support most of the oyster fishery. The present study provides new information on the distribution, condition, and ecology of the intertidal reefs, and assessed the general utility of high-resolution satellite imagery for routine monitoring of the extent and condition of intertidal oysters. Using online, freely available color imagery and manual interpretation, a total of 782 individual reefs ranging in size from ~3 m2 to 3.9 ha (¼ 9.7 acres) and covering a total of 94 ha (233 ac) of bottom area were mapped. Field inspection and sampling of 100 individual intertidal reefs on November 12–16, 2016, confirmed wide differences in the number and areal coverage of reefs in the three major geographic regions in the Bay: 433 reefs covering a total of 56 ha (139 acres) in the western area (St. Vincent Sound); 113 reefs covering 8 ha (19 acres) in the central area; and 236 reefs covering 30 ha (75 acres) in the eastern area (St. George Sound). Most reefs in the western portion of the bay consisted of recently dead (‘‘box’’) oysters in all size classes, suggesting a recent massive mortality event. Mean densities (all size classes combined) of live oysters in the central and eastern areas were 42.9/m2 (±7.39; 1 SE) and 99.3/m2 (±13.22; 1 SE), respectively, with an overall mean shell height of 23.6 mm. Size-frequency histograms indicated only two year classes of live oysters, and the largest oyster collected was 84 mm. Although detailed quantitative comparisons with subtidal reefs were not possible, data from the present study suggest that intertidal reefs cover much less bottom area of the bay, but may contain much higher live oyster densities. The present study also demonstrated the use of high-resolution satellite imagery for mapping reefs as small as a few square meters in surface area, and the potential for estimating relative reef condition measured by live oyster density.

Parameters

Acreage (hectares and acres), density (oysters/m^2), shell height (mm)

Notes

Attributes of XLS table include Total # of live oysters = Number of Oysters Measured - Live Total # of dead oysters = Number of Oysters Measured - Dead Calculations: Add the two to calculate Number of Oysters Measured - Total, and then Percent Live Mean height (mm) = Shell Height KML File contains polygon areas of Acreage. The spreadsheet shows a count of oysters. The quadrat is 0.1 m^2. Multiply count x 10 for # / 1m^2. SampleDate for Oyster acreage set to ‘10/1/2015’ since the methods indicated “Google Earth imagery obtained in December 2013 and October 2015”

Application

Publications

Scientific paper

Start

2016

End

2016

Frequency

One-time

Method

Random quadrat method: total weight of live and dead oysters, counts of live oysters and shell height (nearest mm) for a minimum of 30 randomly selected live oysters assessed from three randomly placed 0.1 m^2 quadrats per reef. Reef area assessed from aerial imagery taken in 2015 as part of a different study and revised based on the ground-truthing (this study).

Discontinuity

Data Location

By Request

Data Format

Excel

Habitats

Oyster/Oyster Reef

SEACAR Citation

University of New Hampshire. (2016). Distribution and Condition of Intertidal Eastern Oyster (Crassostrea virginica) Reefs in Apalachicola Bay Florida Based on High-Resolution Satellite Imagery. Updated 04/22/2022. Distributed by: SEACAR Data Discovery Interface, Office of Resilience and Coastal Protection, Florida Department of Environmental Protection. https://data.florida-seacar.org/programs/details/5063

Alternative Citation

indicates priority attributes