Projects and Publications:
Marine Mammal Research Programs in South Carolina:
The Marine Mammal Program at the Center for Coastal Environmental Health and Biomolecular Research (CCEHBR) focuses their research on bottlenose dolphins because they are a key ecological resource in understanding, predicting and modeling coastal area conditions. The goals of CCEHBR include identifying contaminants, diseases and fishery impacts on marine mammals, examining temporal and spatial distribution of stranded marine mammals, and relating marine mammal population health, abundance, density, distribution, survival and reproduction success to habitat use and environmental stressors. CCEHBR is capable of marine mammal health and toxicological assessments, post-mortem analysis of stranded marine mammals and in-situ surveillance of marine mammal population distributions and conditions.
Marine Mammal Research at Coastal Carolina University includes oversight of the SCMMSN and focused research projects on the ecology of bottlenose dolphins. Research has focused on ecological and bioenergetic studies of resident salt marsh dolphins, as well as photo-ID contributions to our understanding of the movements and stock structure of coastal migratory dolphins. Specific studies include a long-term study of a resident population of dolphins in North Inlet, near Georgetown, SC, correlation between bottom type and dolphin distribution in Winyah Bay, the effects of salinity changes on prey and dolphin distribution in North Inlet, a comparison of swimming speeds and energy expenditures for salt marsh versus coastal dolphins and the role of tidal currents in determining dolphin behavior and distribution, and foraging interactions between strand-feeding dolphins and egrets and herons.
Green, M. A., McFee, W. E., and N. Levine. 2010. A GIS analysis of coastal development and trends in bottlenose dolphin strandings in Charleston, SC: implications for coastal marine spatial planning. NOAA Technical Memorandum NOS NCCOS 124. 56 pp.
Abstract: Bottlenose dolphins (Tursiops truncatus) inhabit estuarine waters near Charleston, South Carolina (SC) feeding, nursing and socializing. While in these waters, dolphins are exposed to multiple direct and indirect threats such as anthropogenic impacts (egs. harassment with boat traffic and entanglements in fishing gear) and environmental degradation. Bottlenose dolphins are protected under the Marine Mammal Protection Act of 1972. Over the years, the percentage of strandings in the estuaries has increased in South Carolina and, specifically, recent stranding data shows an increase in strandings occurring in Charleston, SC near areas of residential development. During the same timeframe, Charleston experienced a shift in human population towards the coastline. These two trends, rise in estuarine dolphin strandings and shift in human population, have raised questions on whether the increase in strandings is a result of more detectable strandings being reported, or a true increase in stranding events. Using GIS, the trends in strandings were compared to residential growth, boat permits, fishing permits, and dock permits in Charleston County from 1994-2009. A simple linear regression analysis was performed to determine if there were any significant relationships between strandings, boat permits, commercial fishing permits, and crabpot permits. The results of this analysis show the stranding trend moves toward Charleston Harbor and adjacent rivers over time which suggests the increase in strandings is related to the strandings becoming more detectable. The statistical analysis shows that the factors that cause human interaction strandings such as boats, commercial fishing, and crabpot line entanglements are not significantly related to strandings further supporting the hypothesis that the increase in strandings are due to increased observations on the water as human coastal population increases and are not a natural phenomenon. This study has local and potentially regional marine spatial planning implications to protect coastal natural resources, such as the bottlenose dolphin, while balancing coastal development.
Fair, P., Adams, F., Mitchum, G., Hulsey, T., Reif, J., Houde, M., Muir, D., Wirth, E., Wetzel., Zolman, E., McFee, W., Bossart, G., 2010. Contaminant blubber burdens in Atlantic bottlenose dolphins (Tursiops truncatus) from two southeastern US estuarine areas: Concentrations and patterns of PCBs, pesticides, PBDEs, PFCs, and PAHs. Science of The Total Environment. 408(7), 1577-1597
Abstract: Polychlorinated biphenyls (PCBs), chlorinated pesticides (i.e., dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordanes (CHLs), dieldrin, hexachlorobenzene (HCB), and mirex), polybrominated diphenyl ethers (PBDEs), perfluorinated chemicals (PFCs), and polyaromatic hydrocarbons (PAHs) were measured in blubber biopsy samples collected from 139 wild bottlenose dolphins (Tursiops truncatus) during 2003-2005 in Charleston (CHS), SC and the Indian River Lagoon (IRL), FL. Dolphins accumulated a similar suite of contaminants with a degree PCB dominating (CHS 64%, IRL 72%), followed by a degree DDT (CHS 20%, IRL 17%), a degree CHLs (CHS 7%; IRL 7%), a degree PBDE (CHS 4%, IRL 2%), PAH at 2%, and dieldrin, PFCs and mirex each 1% or less. Together a degree PCB and a degree DDT concentrations contributed a arrow right 487% of the total POCs measured in blubber of adult males. a degree PCBs in adult male dolphins exceed the established PCB threshold of 17mg/kg by a 5-fold order of magnitude with a 15-fold increase for many animals; 88% of the dolphins exceed this threshold. For male dolphins, CHS (93,980ng/g lipid) had a higher a degree PCBs geomean compared to the IRL (79,752ng/g lipid) although not statistically different. In adult males, the PBDE geometric mean concentration was significantly higher in CHS (5920ng/g lipid) than the IRL (1487ng/g). Blubber a degree PFCs concentrations were significantly higher in CHS dolphins. In addition to differences in concentration of PCB congeners, a degree PBDE, TEQ, a degree CHLs, mirex, dieldrin, and the ratios a degree DDE/a degree DDT and trans-nonachlor/cis-nonachlor were the most informative for discriminating contaminant loads in these two dolphin populations. Collectively, the current a degree PCB, a degree DDT, and a degree PBDEs blubber concentrations found in CHS dolphins are among the highest reported values in marine mammals. Both dolphin populations, particularly those in CHS, carry a suite of organic chemicals at or above the level where adverse effects have been reported in wildlife, humans, and laboratory animals warranting further examination of the potential adverse effects of these exposures.
Powell, J., Archibald, R., Cross, C., Rotstein, D., Soop, V., McFee, W., 2009. Multiple congenital cardiac abnormalities in an Atlantic bottlenose dolphin (Tursiops truncatus). J. Wildl Dis. 45(30).
Abstract: Necropsy of an Atlantic bottlenose dolphin (Tursiops truncatus) neonate that stranded dead on Folly Beach, Charleston County, South Carolina, USA, on 17 November 2007, revealed multiple congenital heart malformations. Cardiac anomalies included a hypertrophic right ventricle, ventricular septal defect (VSD), aortic dilation, atrial septal defect (ASD) between a functionally common atrium and a left atrial remnant, subvalvular pulmonic stenosis, and a hypoplastic pulmonary artery and mitral valve. Few incidences of abnormal cardiac development in cetaceans have been published. The case study serves to document a novel congenital heart malformation not previously reported, to our knowledge, in free-ranging bottlenose dolphins.
McFee, W., Lipscomb, T., 2009. Major pathologic findings and probable causes of mortality in bottlenose dolphins stranded in South Carolina from 1993 to 2006. J. Wildl. Dis. 45(3).
Abstract: Although cause-of-death information on bottlenose dolphins (Tursiops truncatus) can be located in the literature, few citations include mortality data over a long period of time covering a broad geographic region. This study describes major pathologic findings and probable causes of death of bottlenose dolphins over a 14-yr period (1993-2006) for the coastal region of South Carolina. Probable causes of death for 97 cases were determined based on gross pathology and histopathology. In an additional 30 cases, probable cause of death was apparent from gross pathology alone, and carcass condition precluded histopathology. Of the 97 dolphins examined grossly and histologically, 30 (31%) likely died of infectious disease and 46 (47%) of noninfectious disease; the cause of death was unknown in 21 (22%). Bacterial infections accounted for the large majority of fatal infections and emaciation was the leading cause of noninfectious mortality. Twelve dolphins were killed by human interactions. Of the 30 dolphins diagnosed from gross examination alone, 23 likely died from human interaction and seven were killed by stingray-spine inflictions. Although the absence of consistent use of microbiology, biotoxin analysis and contaminant testing decreases the conclusiveness of the findings, this study has broad implications in establishing baseline data on causes of death of bottlenose dolphins for future studies and for the detection of emerging diseases.
McFee, W., Hopkins-Murphy,S., Schwacke, L., 2006. Trends in bottlenose dolphins (Tursiops truncatus) strandings in South Carolina, USA, 1997-2003: implications for the Southern North Carolina and South Carolina Management Units. J. Cetacean Res. Manag. 8(2), 195-201.
Abstract: Trends in marine mammal stranding rates over multiple years can provide useful information on life history parameters, seasonal and spatial distribution and both natural and human-induced mortality rates when compared with baseline data. Data of bottlenose dolphin (Tursiops truncatus) stranding rates in South Carolina, USA from 1997-2003 were analysed. The objectives of this study were to: (1) compare recent trends in strandings with baseline data (1992-1996) for South Carolina; (2) compare strandings between the Southern North Carolina Management Unit (SNCMU) and the South Carolina Management Unit (SCMU); (3) determine annual, seasonal and spatial trends in bottlenose dolphin strandings; (4) investigate seasonal reproductive trends; and (5) determine the extent to which humans may affect stranding rates (human interactions). Bottlenose dolphins stranded in South Carolina are assumed to be from at least two of the seven management units recognised by the National Marine Fisheries Service in the Western North Atlantic: the SNCMU and the SCMU. During the study period, 302 bottlenose dolphin strandings were reported in South Carolina and stranding counts were analysed using a Generalised Linear Model. Results showed that there were significantly more bottlenose dolphin strandings in the spring and autumn as compared with summer and winter. The effect of season was highly significant for the number of neonate strandings, suggesting a bimodal reproductive cycle in spring and autumn for the study area. A significant increase in the number of strandings of all age classes was found in the autumn for the northern portion of the State (SNCMU), supporting the assumption that bottlenose dolphins from the north migrate into South Carolina waters during this time of year. Rope entanglements was the most common source of human interaction, with the crab pot fishery the most prevalent source of fishery mortality in South Carolina. This study demonstrates the usefulness of a long-term stranding database by increasing knowledge of temporal and spatial patterns and for monitoring neonate and human-induced mortality.
Mattson, M., Thomas, J., Aubin D., 2005. Effects of boat activity on the behavior of bottlenose dolphins (Tursiops truncatus) in waters surrounding Hilton Hand Island, South Carolina. Aquat. Mamm. 31(1), 133-140.
Abstract: During the summer of 1998, the effects of boat activity on the behavior of bottlenose dolphins (Tursiops truncatus) were investigated using 52 shore-based surveys along Hilton Head Island, South Carolina. Temporal autocorrelation indicated data collected on most variables should be analyzed in 6-min intervals. Responses to boats were categorized as "no response," "behavioral response," "change in direction of movement," or "change in both behavior and direction." Multiple boats had a greater influence on dolphin behavior and movement than the presence of a single boat. Dolphin-watching boats, motorboats, shrimp boats, and jet skis affected the group size and behavior of dolphin groups. Dolphin groups responded to dolphin-watching boats during 20% of observations, mainly with a change in both behavior and direction of movement. Motorboats caused a response in dolphins during 55% of observations, with a change in behavior or both behavior and direction. Jet skis had a more dramatic effect on dolphin groups, with 56% of groups changing their behavior and 11% changing both their behavior and direction. Shrimp boats always elicited a response. Dolphin groups changed both their behavior, and direction of movement to follow and feed behind these boats. In contrast, ships rarely caused a response, with groups changing their behavior but not their direction in 11% of observations. As the number of boats in the Hilton Head area increased, dolphin groups heightened responses--that is, changed both behavior and direction of movement. These boat-related effects on bottlenose dolphin behavior are considered "harassment" under the U.S. Marine Mammal Protection Act (1972) and should be scrutinized by agencies responsible for public education and enforcement of protective legislation.
Gubbins, C., 2002. Use of home ranges by resident bottlenose dolphins (Tursiops truncatus) in a South Carolina estuary. J. Mammal. 83(1), 178-187.
Abstract: Abundance, distribution, and ranging patterns of bottlenose dolphins (Tursiops truncatus) in the western Atlantic Ocean are not well understood. As part of an initial attempt to understand their ecology and social structure, I examined the ranging patterns of coastal resident dolphins in South Carolina. From October 1994 through December 1998, I conducted 209 surveys in Calibogue Sound and adjoining coastal waters. Individual dolphins were identified by distinctive fin characteristics and categorized as resident or transient inhabitants based on resighting patterns. Home range boundaries and core use areas were defined for 20 resident dolphins. Resident dolphins occurred in inshore waters, were moderately mobile, exhibited strong site-fidelity, and showed distinct patterns of core use within their home ranges. Ranging patterns exhibited geographic partitioning along environmental and social parameters within the resident population.
McFee, W., Hopkins-Murphy, S., 2002. Bottlenose dolphin (Tursiops truncatus) strandings in South Carolina, 1992-1996. Fish Bull. 100(2), 258-265.
Free PDF file available at http://fishbull.noaa.gov/1002/09mcfeef.pdf
Abstract: From 1992 to 1996, 153 bottlenose dolphin stranded in South Carolina, accounting for 73% of all marine mammal strandings during this period. The objectives of our study were to evaluate data from these strandings to determine 1) annual trends in strandings, 2) seasonal and spatial distribution trends, 3) life history parameters such as sex ratio and age classes, 3) seasonal trends in reproduction, and 4) the extent to which humans have played a role in causing these strandings (human interactions). The results showed that 49% of the bottlenose dolphin strandings occurred between April and July; the greatest number of strandings occurred in July (n=22). There was a significant seasonal increase in the distribution of bottlenose dolphin strandings in the northern portion of the state from November to March Bottlenose dolphin neonates stranded in every month of the year, except March and October, and represented 19.6% of the total number of strandings with known length (n=138). Fifty-five percent (n=15) of bottlenose dolphin neonatal strandings occurred between May and July. Bottlenose dolphins determined to have died as the result of human interaction accounted for 23.1% of the total number of bottlenose dolphin strandings (excluding those for which a determination could not be made). Incidents of bottlenose dolphin entanglements in nets accounted for 16 of these cases.
Zoleman, E., 2002. Residence patterns of bottlenose dolphins (Tursiops truncatus) in the Stono River estuary, Charleston County, South Carolina, U.S.A. Mar. Mamma Sci. 18(4), 8-892.
Abstract: Residence patterns of inshore bottlenose dolphins (Tursiops truncatus) in the Stono River estuary, Charleston County, South Carolina were investigated as part of a larger effort to better understand stock structure of these dolphins along the east coast of the United States. Eighty-seven small-boat surveys for bottlenose dolphins were conducted from October 1994 through January 1996. Dolphins were sighted during all surveys. Approximately 304 h were spent surveying the study area; 64% (n = 196 h) of this time was spent observing and videotaping dolphins. A catalog, containing 112 individually identified dolphins was compiled. Thirty-two percent (n = 36) of identified dolphins were sighted once, while 28% (n = 31) were sighted five or more times. Nineteen percent (n = 21) of identified dolphins were determined to be year-round residents; eight percent (n = 9) seasonal residents. The majority (64%, n = 72) of identified dolphins were sighted in the study area during a single season or in two consecutive seasons and were classified as transients. This study documents the northernmost known site of a resident bottlenose dolphin community on the east coast of the United States, suggesting a complex bottlenose dolphin stock structure.
Beck, K., Fair, P., McFee, W., Wolf, D., 1997. Heavy metals in livers of bottlenose dolphins stranded along the South Carolina coast. Mar. Pollut. Bull. 34(9), 734-739.
Abstract: Coastal areas are the most productive systems in terms of providing important nursery areas and habitats, but they are also the repository for toxic agents and hazardous materials from industrial, agricultural and urban sources. Numerous sources contribute heavy metals, sewage wastes and many organic compounds. Ingestion of heavy metals in food or absorption via the water by marine mammals may result in the bioaccumulation of these elements in their tissues. At higher concentrations, these metals can become toxic and cause multiple symptomatic effects influencing the health and survival of these animals. Major toxic metals exerting such effects and included in this study are arsenic, cadmium, chromium, lead and mercury. Elements in this study that are generally noted as essential but are potentially toxic include copper, selenium and zinc.
McFee, W., Root, H., Friedman, R., Zolman, E., 1997. A stingray spine in the scapula of a bottlenose dolphin. J. Wildl. Dis. 33(4), 921-924.
Abstract: A stingray spine was found lodged in the scapula of a deceased 272 cm, male bottlenose dolphin (Tursiops truncatus) from South Carolina (USA) following skeletal preparation, nearly 6 mo after necropsy. No external puncture wound, internal bruising, or laceration of muscle tissue surrounding the scapula was evident during necropsy of the animal. Implantation of the spine did not appear to be related to the death of the dolphin, but probably occurred at an early age. Abnormal development of bone surrounding the spine resulted in the formation of a cavity at the wound site. Two mechanisms were considered as contributors for the cavity formation. These were the mechanical action of the spine stimulating the body's defense system for managing foreign objects, and the release of potent toxins from the spine sheath.
McFee, W., Wolf, D., Parshlev, D., Fair, P., 1996. Investigation of marine mammal entanglement associated with a seasonal coastal net fishery. NOAA Technical Memorandum NOS NCCOS 386. 111 pp.
Abstract: An ocean gillnet fishery for American shad (Alosa sapidissima) operates during the months of February to April in South Carolina waters. As with many other fisheries along the southeastern United States coast, this fishery has not been well characterized in terms of effort, landings, bycatch, and impact on marine mammals. The study was initiated when twelve (12) cetacean strandings, comprising five (5) species, occurred during the South Carolina shad fishing season in the area of shad fishery effort in 1993. The main objectives were to (1) investigate the potential impact of the ocean shad fishery on marine mammal mortality and (2) describe the ocean shad fishery. Aerial surveys were conducted during Year 1 (1994) of the study to document the spatial coverage of shad fishery effort and determine mammal strandings. Boat surveys were added to the aerial surveys for Year 2 (1995) to further characterize the shad fishery and document dolphin/net interactions. One stranding of a bottlenose dolphin (Tursiops truncatus) occurred during Year 1 in the area of effort, and it was determined not to be related to the fishery.
Young, R.F. and H.D. Phillips. 2002. Primary production required to support bottlenose dolphins in a salt marsh creek system. Marine Mammal Science 18(2):358-373.
Abstract: We developed a model to estimate the proportion of annual primary production required to support bottlenose dolphins within the 32-km2 North Inlet salt marsh creek system in South Carolina, U. S. A. The estimated annual prey consumption by dolphins was compared to the total annual production of prey available to dolphins, as determined from estimates of annual primary production, trophic transfer efficiencies, and the mean trophic level of prey. A best estimate range of 3.2%-6.8% of the total annual primary production of the North Inlet system was required to support an average population of only six dolphins (maximum range of 0.4%-7.0%). Dolphins were estimated to consume 11.1-14.2 metric tons of fish (wet weight) each year in North Inlet. The proportion of North Inlet primary production required to support dolphins increased dramatically during the winter months, when primary production declined but dolphin numbers remained similar. This period was marked by a decline in the abundance of available prey species and by a shift in the creek utilization patterns of dolphins. Despite the numerical scarcity of dolphins, they appear to have a significant ecological impact and may be important predators of overwintering prey species.
Young, R.F. and S. Peace. 1999. Using simultaneous counts by independent observers to correct for observer variability and missed sightings in a shore-based survey of bottlenose dolphins, Tursiops truncatus. Journal of Cetacean Research and Management, 1(3):279-287.
Abstract: Simultaneous counts by independent shore-based observers have been used to generate revised population estimates for gray and bowhead whales, but a similar technique has never been applied to shore-based dolphin surveys. Shore-based whale surveys generally rely on a single observation site from which migrating whales are counted as they pass in one direction over a period of weeks to months. Shore-based dolphin surveys, however, typically use multiple observation sites over a much shorter time period (hours) in order to avoid double counting individuals as they change direction. We developed a technique to correct for observer variability and missed sightings for coastal bottlenose dolphin surveys conducted in Myrtle Beach, South Carolina, USA. Comparisons were made between concurrent counts by 39 pairs of independent shore-based observer teams. A model was developed to revise observer estimates in which the number of observed dolphin groups was multiplied by a correction factor to estimate the true number of groups, and this number in turn was multiplied by the mean group size to determine the total number of dolphins. The true number of dolphin groups was estimated using a modified Petersen mark-recapture estimate, stratified by group-size category. The mean proportion of groups missed by observers was negatively correlated with reported group size: 32.7% for groups of 1-2 dolphins; 16.5% for groups of 3-4 dolphins; and 9.9% for groups of >4 dolphins. A variability factor was also calculated to determine a confidence interval for the average number of dolphins per group, based on the mean percent difference between paired observer teams, stratified by group size. The model was used to calculate revised estimates for shore-based bottlenose dolphin surveys conducted in South Carolina in 1994 and 1995. The original uncorrected abundance estimates were increased by a factor of 1.14 and 1.19 respectively, comparable to similar calculations from shore-based surveys of gray whales. However, the estimated confidence interval of ± 38% of the revised estimates is approximately four times the magnitude found in the gray whale studies. This difference is primarily due to the large observer variability for estimated dolphin group size and can be reduced using various revisions of survey design and methodology. Ideal conditions for this technique include elevated observer posts and accurate estimates of the proportion of the population within visual range of the coastline. This study demonstrates that shore-based dolphin surveys are a potentially efficient census technique and an attractive low cost alternative to aerial and boat surveys.