Pilot investigation of remote sensing for intertidal oyster mapping in coastal South Carolina: a methods comparison

South Carolina’s oyster reefs are a major component of the coastal landscape. Eastern oysters Crassostrea virginica are an important economic resource to the state and serve many essential functions in the environment, including water filtration, creek bank stabilization and habitat for other plants and animals. Effective conservation and management of oyster reefs is dependent on an understanding of their abundance, distribution, condition, and change over time. In South Carolina, over 95% of the state’s oyster habitat is intertidal. The current intertidal oyster reef database for South Carolina was developed by field assessment over several years. This database was completed in the early 1980s and is in need of an update to assess resource/habitat status and trends across the state. Anthropogenic factors such as coastal development and associated waterway usage (e.g., boat wakes) are suspected of significantly altering the extent and health of the state’s oyster resources. In 2002 the NOAA Coastal Services Center’s (Center) Coastal Remote Sensing Program (CRS) worked with the Marine Resources Division of the South Carolina Department of Natural Resources (SCDNR) to develop methods for mapping intertidal oyster reefs along the South Carolina coast using remote sensing technology. The objective of this project was to provide SCDNR with potential methodologies and approaches for assessing oyster resources in a more efficiently than could be accomplished through field digitizing. The project focused on the utility of high-resolution aerial imagery and on documenting the effectiveness of various analysis techniques for accomplishing the update. (PDF contains 32 pages)

Spatial and temporal analysis of bottlenose dolphin strandings in South Carolina, 1992-2005

This CD contains summary data of bottlenose dolphins stranded in South Carolina using a Geographical Information System (GIS) and contains two published manuscripts in .pdf files. The intent of this CD is to provide data on bottlenose dolphin strandings in South Carolina to marine mammal researchers and managers. This CD is an accumulation of 14 years of stranding data collected through the collaborations of the National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research (CCEHBR), the South Carolina Department of Natural Resources, and numerous volunteers and veterinarians that comprised the South Carolina Marine Mammal Stranding Network. Spatial and temporal information can be visually represented on maps using GIS. For this CD, maps were created to show relationships of stranding densities with land use, human population density, human interaction with dolphins, high geographical regions of live strandings, and seasonal changes. Point maps were also created to show individual strandings within South Carolina. In summary, spatial analysis revealed higher densities of bottlenose dolphin strandings in Charleston and Beaufort Counties, which consist of urban land with agricultural input. This trend was positively correlated with higher human population levels in these coastal counties as compared with other coastal counties. However, spatial analysis revealed that certain areas within a county may have low human population levels but high stranding density, suggesting that the level of effort to respond to strandings is not necessarily positively correlated with the density of strandings in South Carolina. Temporal analysis revealed a significantly higher density of bottlenose dolphin strandings in the northern portion of the State in the fall, mostly due to an increase of neonate strandings. On a finer geographic scale, seasonal stranding densities may fluctuate depending on the region of interest. Charleston Harbor had the highest density of live bottlenose dolphin strandings compared to the rest of the State. This was due in large part to the number of live dolphin entanglements in the crab pot fishery, the largest source of fishery-related mortality for bottlenose dolphins in South Carolina (Burdett and McFee 2004). Spatial density calculations also revealed that Charleston and Beaufort accounted for the majority of dolphins that were involved with human activities. 1

Longevity and Persistence of Triploid Grass Carp Stocked into the Santee Cooper Reservoirs of South Carolina

This study evaluated longevity and population persistence of 768,500 triploid grass carp (Ctenopharyngodon idella Valenciennes) stocked in the 70,000-ha Santee Cooper system in South Carolina from 1989 through 1996 to control hydrilla (Hydrilla verticillata (L.f.) Royle).

Population response of triploid grass carp to declining levels of hydrilla in the Santee Cooper Reservoirs, South Carolina

Approximately 768,500 triploid grass carp ( Ctenopharyngodon idella Valenciennes) were stocked into the Santee Cooper reservoirs, South Carolina between 1989 and 1996 to control hydrilla ( Hydrilla verticillata (L.f.) Royle). Hydrilla coverage was reduced from a high of 17,272 ha during 1994 to a few ha by 1998. During 1997, 1998 and 1999, at least 98 triploid grass carp were collected yearly for population monitoring. Estimates of age, growth, and mortality, as well as population models, were used in the study to monitor triploid grass carp and predict population trends. Condition declined from that measured during a previous study in 1994. The annual mortality rate was estimated at 28% in 1997, 32% in 1998 and 39% in 1999; however, only the 1999 mortality rate was significantly different. Few (2 out of 98) of the triploid grass carp collected during 1999 were older than age 9. We expect increased mortality due to an aging population and sparse hydrilla coverage. During 1999, we estimated about 63,000 triploid grass carp system wide and project less than 3,000 fish by 2004, assuming no future stocking. management, population size Ctenopharyngodon idella, Hydrilla