Abstract:

Shell heights of up to 20 live oysters per size class (spat, seed, market) found in oyster reefs sampled in the early fall (September/October) and spring (April/May) in 2015-2016. Four embayments were sampled from Louisiana to the Florida panhandle, with sites that were previously oiled or non-oiled after the Deep Water Horizon Oil Spill. Within oiled and non-oiled sites, oyster quadrat samples were taken from intertidal, nearshore (along the marsh edge) and subtidal areas, and also from mesohaline and high salinity sites. The top 10 cm of material was collected from the quadrats and returned to the lab for measurement of shell height by calipers.

Suggested Citation:

Meagan Shrandt, Sean Powers. 2017. Oyster shell heights in 2015-2016 among previously documented oiled and non-oiled reefs in Louisiana, Alabama, and the Florida panhandle. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7WS8R84

Purpose:

The purpose of this dataset is to describe the distribution of oyster sizes in areas with documented exposure to oil from the Deepwater Horizon Oil Spill in 2010, as well as control sites (no documented oil exposure). These oyster shell height measurements will help determine the recovery trajectories of oysters in the northern Gulf of Mexico in regards to oiling and the associated response activities.

Data Parameters and Units:

Year = the year of sampling Mo = the calendar month of sampling Day = the calendar day of sampling for any given month Time_CST = the time the oyster reef site was sampled; in Central Standard Time Site = the ID given to the sampled site; the first two letter correspond to the embayment Embayment = the generic sampling embayment where the reef can be found; options (4) include: Mississippi Sound, Barataria Bay, Terrebonne Bay, Florida Basin = location of the oyster reef within the generic sampling embayment: options (26) include: Airport Marsh; Alabama Port; Apalachicola Bay; Barataria Bay, east; Barataria Bay, north; Bay Junop, north; Bay Junop, south; Caillou Lake, north; Coffee Island; Dauphin Island; Dauphin Island Bay; DI Shoals, northwest; East Bay Panama City; East Bay Pensacola; Escambia Bay, Pensacola; Grand Isle; Grand Terre; Hackberry Bay; Heron Bay; Little Dauphin Island; North Bay Panama City; Pensacola Bay, west; Portersville Bay; Terrebonne Bay, north; Terrebonne Bay, west; West Bay Panama City State = the US state where the oyster reef site is located; options (3) include: Louisiana, Alabama, Florida Lat = latitude of oyster reef site (WGS1984) Long = longitude of oyster reef site (WGS1984) Near_Sub = the tidal regime for the site; options (2) include: nearshore (intertidal, along the marsh edge) and subtidal OilingCat = the oiling category assigned to the site; based on categories assigned by the Natural Resource Damage Assessment and Shoreline Cleanup and Assessment Technique (SCAT) maps for non-NRDA sites; categories (2) include: oiled, not oiled SalinityCat = the salinity group assigned to the oyster site, based on the measurement of salinity taken at the time of sampling in 2015; options (2) include meso and high. For Barataria and Terrebonne Bays, high salinity is considered greater than or equal to 19 ppt. For Mississippi Sound, high salinity is considered to be greater than or equal to 21 ppt. The difference in values is based on the differing salinity regimes in each embayment. WaterTemp_C = water temperature just above the reef at the time of sampling; units are degrees Centigrade Salinity_ppt = salinity just above the reef at the time of sampling; units are ppt (parts per thousand) DO_mgL = dissolved oxygen just above the reef at the time of sampling; reading was taken as close to the oyster reef as possible (surface for intertidal and just above the reef for subtidal reefs); units are mg per L QuadratRep = the quadrat number at the site; a total of 3 quadrats were sampled at each oyster reef site; options (3) include: Q1, Q2, Q3 SampleID = the ID for the quadrat sample taken at the oyster reef; this ID has the format Site-QuadratRep; for example: MS01-Q1 is quadrat 1 from oyster reef number 01 in Mississippi Sound *The following are three groups of 21 columns. The first 20 in the set are measurements of up to 20 individual oysters within that size class. The 21st column is the average shell height. Spat1 – Spat20 = the shell height of individual oyster spat; up to 20 oysters were measured per quadrat; shell height was measured as the distance between the umbo and most distal valve margin; units are mm SpatAveSH_mm = the average shell height of spat-sized oysters; units are mm Seed1 – Seed20 = the shell height of individual oyster seed; up to 20 oysters were measured per quadrat; shell height was measured as the distance between the umbo and most distal valve margin; units are mm SeedAveSH_mm = the average shell height of seed-sized oysters; units are mm Market1 – Market20 = the shell height of individual market-sized oysters; up to 20 oysters were measured per quadrat; shell height was measured as the distance between the umbo and most distal valve margin; units are mm MarketAveSH_mm = the average shell height of market-sized oysters; units are mm

Methods:

Four embayments were sampled from Louisiana to the Florida panhandle, with sites that were previously oiled or non-oiled after the Deep Water Horizon Oil Spill. Within oiled and non-oiled sites, oyster quadrat samples were taken from intertidal, nearshore (along the marsh edge) and subtidal areas, and also from mesohaline and high salinity sites. The top 10 cm of material was collected from the quadrats and returned to the lab for enumeration of species.

Individual Files: