Abstract:

Oysters were monitored for Perkinsus marinus (Dermo disease) infection intensity quarterly from 2014 to 2021 in the Mission-Aransas Estuary. At least seven reefs were sampled in each sampling event (quarter). Associated water quality variables (salinity, temperature, dissolved oxygen, pH, turbidity) were monitored quarterly from 2014 to 2021, including at the times of oyster collection from 2014 to 2021.

Suggested Citation:

Beseres Pollack, Jennifer, Natasha Breaux, Terence A. Palmer, Kelley B. Savage, Kevin De Santiago, and Danielle Downey. 2022. Monitoring of Perkinsus marinus (Dermo disease) infection intensity in the Crassostrea virginica, and water quality in the Mission-Aransas Estuary, 2014-2021. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/JJZYJ9AT

Purpose:

Data were collected to help determine the relationship between climatic conditions, salinity regimes, and P. marinus infections in Crassostrea virginica. The hypothesis is that climatic conditions (e.g., drought, normal, wet) are correlated with salinity patterns and with P. marinus infection levels within a spatial salinity gradient. The effects of water quality (and indirectly climate) on P. marinus were investigated along a spatial salinity gradient within the Mission-Aransas Estuary over time.

Data Parameters and Units:

Date (ddMMMyyyy), Oyster height (mm), temperature (°C), specific conductance (mS/cm), salinity (PSU), dissolved oxygen (% and mg/L), pH, turbidity (NTU), secchi disc (m), dermo intensity, (0-5 scale), oyster condition (1-9 scale), oyster bill condition (sharp, regressed)

Methods:

At least seven stations were sampled quarterly along a salinity gradient in the Mission-Aransas Estuary from 2014 to 2021 to measure oyster characteristics and water quality. At each station up to 20 oysters (~10 market size (≥ 76 mm) and ~10 sub-market size (26-75 mm)) were collected using an oyster dredge. At each station, depth, temperature, conductivity, dissolved oxygen, salinity, pH, and turbidity were measured with a Hydrolab Surveyor II or YSI Pro DSS 10 cm from the water surface and approximately 10 cm above the bay bottom. For each oyster, oyster condition was rated based on criteria in Quick and Mackin 1971, and P. marinus infection was assessed using Ray’s Fluid Thioglycollate Method (Ray 1966). To determine P. marinus infection, a 5 x 5 mm section of mantle tissue was removed and incubated in Ray’s Fluid Thioglycollate Media (RFTM) for 2 weeks following the culture method of Ray (1966). Tissue cultures were then stained with 75% Lugol’s solution and examined microscopically for P. marinus hypnospores (blue/black spheres). P. marinus intensity was scored using the 6-point Mackin scale (uninfected (0) - heavily infected (5)) adapted from Mackin (1962) by Craig et al. (1989). The proportion of oysters infected with P. marinus (prevalence) was calculated by dividing the number of infected oysters by the number of oysters sampled. Mean infection intensity (II) of individuals on the reef was calculated (Soniat et al. 2012), and then weighted prevalence, a measure of the relative severity of P. marinus infection in a population, was calculated by multiplying mean infection intensity by prevalence.

Instruments:

Hydrolab Surveyor II, YSI ProDSS, calipers

Provenance and Historical References:

Craig A., E.N. Powell, R.R. Fay, and J.M. Brooks. 1989. Distribution of Perkinsus marinus in Gulf Coast oyster populations. Estuaries. 12:82-91. DOI:10.2307/1351499 Mackin, J.G. 1956. Dermocystidium marinum and other micro-organisms in Louisiana. Publ Inst Marine Science University Texas. 7:132-229. Mackin, J.G. 1962. Oyster disease caused by Dermocystidium marinum and other microorganisms in Louisiana. Publ. Inst. Marine Science University Texas. 7:132-299. Quick, J.A., Jr., and J. G. Mackin. 1971. Oyster parasitism by Labyrinthomyxa marina in Florida. Fla. Dept. Nat. Resour. Mar. Res. Lab. Prof. Pap. Ser. No. 13. 55p Ray, S.M. 1966. A review of the culture method for detecting Dermocystidium marinum, with suggested modifications and precautions. Proceedings of the National Shellfisheries Association. 54:55–69. Soniat, T.M., J.M. Klinck, E.N. Powell and E.E. Hofmann. 2012. Understanding the success and failure of oyster populations: periodicities of Perkinsus marinus and oyster recruitment, mortality, and size. Journal of Shellfish Research. 31:635-646. DOI: 10.2983/035.031.0307

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