Data Description

Data Description

Vibrio parahaemolyticus concentrations in oyster tissue were determined using a 3-tube Most Probable Number overnight (18-20 h) enrichment of decimally diluted samples in alkaline peptone water. Turbid tubes were streaked onto TCBS or CHROMagar Vibrio and incubated at 37°C for 18 – 20 hours. Pure cultures of isolates were subjected to species identification by a standard PCR-based assay using the species-specific gene (tlh) to determine V. parahaemolyticus MPN values.

Environmental data used in the statistical analyses were collected as part of the Great Bay National Estuarine Research Reserve (GBNERR) System Wide Monitoring Program. Fifteen-minute temperature, salinity, dissolved oxygen, pH, depth and turbidity were collected by GBNERR datasondes deployed in the Great Bay from April-December. Precipitation data were acquired from several weather stations (; in the Great Bay region. Surface (0.5 m depth) water temperature, salinity, dissolved oxygen, and pH data were also measured using YSI 6600 and EXO data sondes (YSI Inc., Yellow Springs, Ohio) at the time of sampling to check the accuracy of GBNERR datasonde readings. In addition, analysis included monthly nutrient data, including chlorophyll a (Chla), phosphate (PO4), and total dissolved nitrogen (TDN), were collected by the GBNERR SWMP ( Chlorophyll a was determined using EPA Method 445.0.

Oyster samples were collected at the two study sites by boat using oyster tongs, and water samples were collected from 0.5 m depths using sterile bottles. Water column measurements were made using a YSI 6600 datasonde equipped with pH, temperature, salinity, dissolved oxygen and depth sensors.


Reports from state health departments and the Centers for Disease Control and Prevention indicate that the annual number of reported human vibriosis cases in New England has increased in the past decade. Concurrently, there has been a shift in both the spatial distribution and seasonal detection of Vibrio spp. throughout the region based on limited monitoring data. To determine environmental factors that may underlie these emerging conditions, this study focuses on a long-term database of Vibrio parahaemolyticus concentrations in oyster samples generated from data collected from the Great Bay Estuary, New Hampshire during warm summer months over a period of seven consecutive years. Oyster samples from two distinct sites were analyzed for V. parahaemolyticus abundance, noting significant relationships with various biotic and abiotic factors measured during the same period of study. We developed a predictive modeling tool capable of estimating the likelihood of V. parahaemolyticus presence in coastal New Hampshire oysters. Results show that the inclusion of chlorophyll a concentration to an empirical model otherwise employing only temperature and salinity variables, offers improved predictive capability for modeling the likelihood of V. parahaemolyticus in the Great Bay Estuary.