Historically, acoustic telemetry studies tracking movement of aquatic organisms have lacked rigorous, long-term evaluations of detection range. The purpose of the present study was to identify potential sources of variability in long-term acoustic telemetry data, focusing specifically on environmental variability. The study was conducted for 15 mo in Gray's Reef National Marine Sanctuary, Georgia, USA, using 2 submersible Vemco VR2W hydrophone receivers and 2 stationary range test transmitters (controls). Tag detections (+/- 1 SE) decreased from 54.2 +/- 2.5 to 11.4 +/- 0.5 detections d(-1) as transmission distance increased from 100 to 300 m. Detections varied seasonally (likely due to stratification), with the direction of flood and ebb tidal currents (12.4 h cycle), and with tidal current speed (6.2 h cycle). Tides explained up to 92% of the short-term variability in hourly detection data. Detections also increased or decreased during episodic weather events depending on the season and type of event. These results suggest that stationary control tags are useful for characterizing variability in sound transmission in open water marine acoustic telemetry studies.

Living gray whales (Eschrichtius robustus) are key consumers in benthic communities of the North Pacific Ocean. Gray whales, however, also inhabited the North Atlantic Ocean until recent historical times (~1600AD), leaving open questions about their historical ecology in nearshore communities of this basin. Here we report the discovery of fossil remains from two individual gray whales recovered from underwater excavations at separate localities of JY Reef, an offshore reef situated approximately 32kilometers (km) offshore of St. Catherine's Island, Georgia, U.S.A. Both mandibles are diagnostic to the living E. robustus. Radiometric dating of shells from JY Reef suggests an approximate age range of these two specimens between 42 and 30thousand years before present (ka). Morphological measurements of the preserved elements indicate that both of the mandibles likely belonged to immature and possibly yearling individuals. Collectively, these findings are among the oldest occurrences of gray whales in the North Atlantic basin, and their presence at temperate latitudes provides limited support for the hypothesis that Atlantic gray whales used a southerly breeding area at the end of a migratory pathway, by analog with lagoonal breeding environments of Baja California, Mexico, for the extant California gray whales, and the breeding areas for the extant North Atlantic right whales (Eubalaena glacialis) off the Georgia coast today. Stronger support for this latter contention may stem from future fossil discoveries in the region, as well as ancillary lines of evidence, such as the remains of species-specific ectoparasites and/or ancient DNA (aDNA).

Direct visual and acoustic observations at subtropical reefs off the southeast United States and northeast Gulf of Mexico revealed a complex web of behavioral interactions within and between mid-water and demersal guilds of piscivorous fishes. While mixed-species groups of mid-water and demersal piscivores stalked and attacked common prey species independently, facilitative behaviors between mid-water and demersal piscivores were common in each region. In the latter case, prey reduced nearest neighbor distances and retreated toward the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. Aggregations of fishes in other trophic guilds, unassociated with predation events, modified movements of prey fishes and provided camouflage for piscivores that occurred within and along the periphery of those aggregations. Demersal piscivores often assumed the role of mid-water piscivores when the abundance of mid-water piscivores was low and when demersal piscivores were larger than mid-water species. Young-of-the-year great barracuda, Sphyraena barracuda (Edwards, 1771), also assumed this role, generally when other piscivores were absent. Such behavioral interactions appear to be common in these communities. If predator-prey relationships are regularly facilitated by these types of mixed-species interactions, such facilitative behaviors may be important in terms of population processes (e.g., yielding increases in prey consumption with resultant increases in growth rate, and fecundity). A framework for testing such predictions provides a pathway for assessing the population consequences of such interactions.

Subfossil evidence, including a nearly complete dentary (similar to 77%) ( left mandible) and two badly eroded vertebrae, of a mysticete whale, were recovered, underwater, from an in situ context, in the Georgia Bight, 30 km offshore St. Catherine's Island, Georgia. The discovery of the mandible was initially made in 2006 but excavation was not completed until the summer of 2008. Two badly preserved vertebrae were found lying nearby having eroded from the same outcrop as the dentary. The two vertebrae were dated but not analyzed in this report. Direct dating of the subfossils, with the Accelerator Mass Spectometry radiocarbon technique (AMS), using bioapatite, rather than collagen, suggests a common age range for the skeletal materials, 34,000 to 37,000 ka, but it's speculative to assign these remains to the same animal or, for that matter, the same taxon. The ages determined for the subfossils are in good agreement with the age of the geological deposit, a shell coquina, as previously determined by AMS dating of inclusions and by direct dating of the sediments using Optical Stimulated Luminescence (OSL) dating. Additionally, amino acid raceminization (AAR) ages were obtained for the coquina. Our comparative analysis supports a diagnosis of a dentary of a mysticete whale. Further comparison of preserved morphological characters with those for mysticete mandibles, support a further diagnosis as balaenopterid or eschrichtiid. Coupled with recent, Pleistocene aged discoveries, in Europe, in the North Sea basin, these remains could provide well-dated, new, North American evidence for the extirpated gray whale in the Atlantic basin of the Quaternary.

During the fall of 2006, scientific divers from University of Georgia, Athens (UGA) and the National Oceanic and Atmospheric Administration (NOAA) were conducting a reconnaissance dive at JY reef approximately 20 nautical miles offshore Georgia. During this dive, a large subfossil bone was discovered partially embedded in the reef. On subsequent dives, loose sand was removed from around the bone and a small section was recovered. This bone fragment was carbon dated to approximately 36,000 years before present. However, since the bone was determined to be much larger than originally thought; not readily recoverable; and would require extensive excavation, a bottom disturbing permit was required. After approximately one year of discussions with multiple state and federal agencies, the United States Army Corps of Engineers issued a permit for excavation. Excavation began in the summer of 2008 and involved cutting through fossilized shell beds before reaching softer, but hard packed silt. Divers worked diligently with hammers, chisels and knives to cut away the overburden and carefully remove the sediment immediately around the bone. After numerous dives, the bone was recovered in sections totaling approximately 1.5 m in length. The bone has been visually identified as a North Atlantic Gray whale mandible. Ongoing work including visual study and DNA extraction is being conducted to verify the species. A joint UGA and Emory University team is currently working to professionally restore the bone and prepare it for display.

Pelagic and demersal guilds of piscivorous fishes are linked by a variety of biological and physical processes that mediate interactions with common prey species. Understanding the behaviors of predators and prey can provide insight into the conditions that make such linkages possible. Here we report on the behaviors of mid-water piscivorous fishes and the responses of prey that produce feeding opportunities for demersal piscivorous fishes associated with "live bottom" ledge habitats off the coast of Georgia (northwest Atlantic Ocean). Prey taxa reduced nearest neighbor distances and retreated towards the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. No predation by demersal fishes was observed when prey species were at background densities. If the predator-prey interactions of demersal piscivorous fishes are commonly mediated by the predatory behavior of midwater piscivorous fishes and their prey, such indirect facilitative behaviors may be important in terms of the population processes (e.g., prey consumption and growth rates) of these demersal fishes.

A recent focus of the National Oceanic and Atmospheric Administration (NOAA) National Marine Sanctuaries Program is the characterization and assessment of marine resources associated with coral reef and live bottom habitats in protected areas. Detailed bottom maps have been produced making it possible to quantify bottom features within Gray's Reef National Marine Sanctuary, Georgia, USA. Hydroacoustic fisheries surveys were used to estimate fish biomass in the context of underlying features and bottom types by applying spatial techniques and regression analysis. Variables relating bottom features to estimated fish biomass differed based upon depth in the water column. Distance to rock ledges was the best predictor of fish biomass in the bottom 2 m of the water column, whereas the area of two bottom habitat types combined was a reliable predictor of estimated fish biomass in the mid water column.

As part of an ongoing program of benthic sampling and related assessments of sediment quality at Gray’s Reef National Marine Sanctuary (GRNMS) off the coast of Georgia, a survey of soft-bottom benthic habitats was conducted in spring 2005 to characterize condition of macroinfaunal assemblages and levels of chemical contaminants in sediments and biota relative to a baseline survey carried out in spring 2000. Distribution and abundance of macrobenthos were related foremost to sediment type (median particle size, % gravel), which in turn varied according to bottom-habitat mesoscale features (e.g., association with live bottom versus flat or rippled sand areas). Overall abundance and diversity of soft-bottom benthic communities were similar between the two years, though dominance patterns and relative abundances of component species were less repeatable. Seasonal summer pulses of a few taxa (e.g., the bivalve Ervilia sp. A) observed in 2000 were not observed in 2005. Concentrations of chemical contaminants in sediments and biota, though detectable in both years, were consistently at low, background levels and no exceedances of sediment probable bioeffect levels or FDA action levels for edible fish or shellfish were observed. Near-bottom dissolved oxygen levels and organic-matter content of sediments also have remained within normal ranges. Highly diverse benthic assemblages were found in both years, supporting the premise that GRNMS serves as an important reservoir of marine biodiversity. A total of 353 taxa (219 identified to species) were collected during the spring 2005 survey. Cumulatively, 588 taxa (371 identified to species) have been recorded in the sanctuary from surveys in 2000, 2001, 2002, and 2005. Species Accumulation Curves indicate that the theoretical maximum should be in excess of 600 species. Results of this study will be of value in advancing strategic science and management goals for GRNMS, including characterization and long-term monitoring of sanctuary resources and processes, as well as supporting evolving interests in ecosystem-based management of the surrounding South Atlantic Bight (SAB) ecosystem. (PDF contains 46 pages)

As part of an ongoing ecological assessment of the Gray's Reef National Marine Sanctuary (GRNMS), a 58-km(2) marine protected area 32 km off the coast of Georgia, USA, surveys of benthic macroinfaunal communities, contaminant levels in sediments and biota, and general habitat conditions were conducted during 2000-2002 at 20 stations within the sanctuary and along three cross-shelf transects in nearby shelf waters. Macroinfaunal community structure and composition exhibited distinct cross-shelf patterns associated with sediment granulometry, depth and possibly other factors related to shoreline proximity (e.g., erosional effects, recruitment of estuarine species). Finer-scale spatial patterns of benthic fauna among stations within the sanctuary appear to be related to proximity to live-bottom habitat and other features of seafloor structure (e.g., rippled vs. flat sand). Population densities of dominant fauna within the sanctuary also varied considerably among years, resulting in shifts in the ranking of dominants at most stations. Chemical contaminants generally were at low background concentrations below probable bioeffect levels and thus are not a likely cause of the observed spatial patterns of benthic fauna. However, trace concentrations of pesticides, PCBs, and PAHs were detectable in sediments and biota throughout the Study area, demonstrating that chemicals originating from human activities are capable of reaching the offshore sanctuary environment, possibly from atmospheric deposition or cross-shelf transport of materials outwelled through coastal sounds. Highly diverse infaunal assemblages also were observed within the sanctuary and nearby sites of similar depth, suggesting that the sanctuary is an important reservoir of marine biodiversity. Results of this study should be useful in addressing long-term science and management needs of the GRNMS and in furthering our understanding of broader ecological patterns and dynamics of the surrounding South Atlantic Bight (SAB) ecosystem.

In 2003, twelve marine protected areas were established in state waters (0-3 nmi) surrounding the Channel Islands. NOAA is considering extending this network (3-6 nmi) into deeper waters of the Channel Islands National Marine Sanctuary (CINMS). In order for effective long-term management of the deep water reserves to occur, a well-structured monitoring program is required to assess effectiveness. The CINMS and the National Marine Sanctuary Program (NMSP) hosted a 2-day workshop in April 2005 to develop a monitoring plan for the proposed federal marine reserves in that sanctuary. Conducted at the University of California at Santa Barbara, participants included scientists from academic, state, federal, and private research institutions. Workshop participants developed project ideas that could answer priority questions posed by the NMSP. This workshop report will be used to develop a monitoring plan for the reserves. (PDF contains 47 pages.)

Direct visual and acoustic observations at subtropical reefs off the southeast u n ited s t ates and northeast Gulf of m e xico revealed a complex web of behavioral interactions within and between mid-water and demersal guilds of piscivorous fishes. While mixed-species groups of mid-water and demersal piscivores stalked and attacked common prey species independently, facilitative behaviors between mid-water and demersal piscivores were common in each region. i n t he latter case, prey reduced nearest neighbor distances and retreated toward the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. ag gregations of fishes in other trophic guilds, unassociated with predation events, modified movements of prey fishes and provided camouflage for piscivores that occurred within and along the periphery of those aggregations. Demersal piscivores often assumed the role of mid-water piscivores when the abundance of mid-water piscivores was low and when demersal piscivores were larger than mid-water species. Young-of-the-year great barracuda, Sphyraena barracuda (e d wards, 1771), also assumed this role, generally when other piscivores were absent. s uch behavioral interactions appear to be common in these communities.