Video-Based Mapping of Oyster Bottom in the Upper Piscataqua River, Sturgeon Creek, and Spruce Creek. A Final Report to The Piscataqua Region Estuaries Partnership. Date of the Report January 21, 2009

摘要

Towed, underwater videography was used to map and characterize the extent of oyster bottom in the upper Piscataqua River, Sturgeon Creek, and Spruce Creek. Georeferenced video imagery was obtained on five different days in summer and fall 2008. Significant shell bottom (with live oysters in most areas) was found only in the upper Piscataqua River in two areas: (1) the general location of the previously mapped (2003) upper Piscataqua River reef, and (2) in the Piscataqua River at the mouth of Sturgeon Creek. The Sturgeon Creek reef was classified into low and high density shell which covered a total area of 15.6 acres (approx. 63,000 m2). Recommendations included additional survey work in the lower Salmon Falls and Cocheco Rivers, and Spruce Creek. This project was designed to provide new information on the distribution of eastern oysters (Crassostrea virginica) in three general areas: upper Piscataqua River, Sturgeon Creek, and Spruce Creek. Most of these areas had not been surveyed since the 1970s. A towed, underwater videography system with onboard GPS unit was deployed for a total of five days in June, August, October and November 2008. Georeferenced video imagery was recorded along a total of 12.3 km of shiptracks. The imagery was classified into non-reef (50% shell cover and live oysters). The major finding of the surveys was a live oyster reef which covered a bottom area of 15.6 Acres (63,000 m2) at the mouth of Sturgeon Creek. Based on the size of live oysters visible in the video imagery, this reef appeared to be the result of the excessively high 2006 spat set that occurred in many areas. In comparison to other oyster reefs in the Piscataqua region, the Sturgeon Creek reef ranks third in total bottom areal coverage. Based on findings from the present project, additional video surveys are recommended for three areas: the entire upper Piscataqua River/ lower Salmon Falls River, the Cocheco River, and Spruce Creek. These surveys would result in a more complete inventory of the areal extent of oyster resources in the Piscataqua region.