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Abstracts of Oral Presentations

ASSESSING THE RELATIONSHIP BETWEEN GEOMORPHOLOGY AND DEEP-SEA MEGAFAUNAL COMMUNITIES ON THE WEST FLORIDA ESCARPMENT

Proux, Z (GPMB, University of Charleston, SC)

The Gulf of Mexico has the highest diversity of deep-sea coral anywhere in the United States.  The distribution of deep-sea corals, and other sessile megafauna, depends primarily on depth, presence of hard substrate, and vertical relief of the seafloor, but less is known about how those assemblages vary with different geomorphologic features. Flats, mounds, and ridges are common geomorphologic features on the West Florida Escarpment. The primary goal of this study was to compare abundance, composition, and diversity of deep-sea megafaunal assemblages as they relate to flats, mounds, and ridges. This study focused on four proposed Habitat Areas of Particular Concern (pHAPC) recommended for regulation by the Gulf of Mexico Fishery Management Council with depths between ~300 and 750 m. High-resolution multibeam echo sounder data from surveys by NOAA Ship Nancy Foster in 2008 and R/V Falkor in 2012 provided reference surfaces. Additionally, megafauna greater than 10 cm were identified and enumerated in 146 transects from 22 ROV dives. Species accumulation curves identified ridges as the most species rich geomorphology type and flats as the least species rich. A non-metric multidimensional scaling ordination (nMDS) based on an underlying Bray-Curtis similarity matrix and the ANOSIM Global-R statistic determined communities were significantly different between flats, mounds, and ridges. Future expeditions onto the West Florida Escarpment can use geomorphology as a proxy when looking for specific assemblages. Furthermore, managers can use geomorphology to classify large areas of seafloor that have been mapped, but not explored by ROV.



A LIFE HISTORY STUDY OF THE GOBIID FISH GOBIOSOMA BOSC IN SOUTH CAROLINA ESTUARIES

Taylor, MA (GPMB, University of Charleston, SC)

Gobiosoma bosc is a scale-less, cryptic, short-lived goby abundant in shallow coastal habitats, oyster reefs, and estuaries throughout its geographic range. Previous studies on the reproductive life history of G. bosc failed to include aging or histological analyses, therefore basic knowledge of G. bosc population demographics and reproductive biology remain unknown. The aim of the current study is 1) to determine the age and growth rates for individuals of all size classes for both sexes of G. bosc; 2) determine the duration of the spawning season and spawning periodicity for populations of G. bosc within the Charleston Harbor; and 3) histologically verify the sexual strategy and reproductive biology of G. bosc. Specimens have been collected from the Charleston Harbor, Charleston SC and Waddell Mariculture Center, Bluffton, SC monthly beginning in May 2017. Prior to fixation, sagittal otoliths were removed from taxonomically identified specimens for aging and growth analyses. Formalin-fixed dissected gonad tissue and surrounding viscera were sectioned and sequentially mounted to obtain a full cross-sectional series of the gonad. Histological analyses provide descriptions of the sexual strategy and reproductive biology of some G. bosc populations in South Carolina estuaries. Results from this study will provide data necessary for population assessments of G. bosc and their ecological role within oyster reefs and estuarine ecosystems.


METABOLIC RESPONSE TO HIGH WATER TEMPERATURES IN CULTURED JUVENILE RED DRUM, SCIAENOPS OCELLATUS

Welling, E (GPMB, University of Charleston, SC)

Estuarine organisms are exposed to high water temperatures which reduces water oxygen concentration and increases fish metabolic rate and overall oxygen demand. Routine and maximum metabolic rates (RMR and MMR) increase with temperature to maximum values at their optimum temperatures and decrease as temperatures increase past optimum. Aerobic scope, the difference between MMR and RMR, represents aerobic metabolic capacity, and reduced aerobic scope may inhibit physiological performance and alter behavior. When aerobic metabolism cannot meet the full demand, anaerobic metabolism supplements demand but may cause pH shifts and a large oxygen debt. This study investigates the effect of high temperature on the metabolism of juvenile red drum. Oxygen consumption was measured at four temperatures mimicking summer temperatures: 24°C, 27, 30°C, and 33°C. Fish were starved, and RMR was measured overnight. To estimate MMR, fish were chased until exhaustion and placed back into the respirometer. Another set of fish were exercised and immediately sacrificed. Lactate concentration will be quantified from these fish and used as a anaerobic metabolism indicator. RMR was 13.47 ± 0.67 mmol kg-1 h-1 at 24°C and increased with temperature to a maximum value of 17.49 ± 0.87 mmol kg-1 h-1 at 33°C. MMR and aerobic scope peaked at 27°C and decreased at temperatures lower and higher than this optimum. Red drum aerobic scope did not decrease significantly at the highest temperature tested, and so fish performance in the wild may not be reduced at high summer temperatures.


LARVAL SURVIVAL AND SETTLEMENT IN THE COMMENSAL BARNACLE CHELONIBIA TESTUDINARIA UNDER DIFFERING SALINITY CONDITIONS

Reilly, M (GPMB, University of Charleston, SC)

Chelonibia testudinaria is an epibiotic acorn barnacle that attaches to sea turtles, manatees, and crabs. Much is unknown about the mechanisms by which this epibiont finds its host during the planktonic larval stage. This study identified the salinity tolerance of C. testudinaria larvae in order to understand what water masses they are likely to occur and also be able to settle on a host. Egg masses were collected from adult barnacles growing on horseshoe crabs and sea turtles. Larvae were reared in filtered seawater at 20 or 30 ppt salinity until they reached the cyprid stage and then groups of cyprids from the same cohort were transferred into beakers with salinities at 10, 15, 20, 25, and 30 ppt respectively. After 72 hours all cyprids were counted and classified as alive, settled, metamorphosed, or dead. Percent mortality and percent settlement were calculated based on total larvae per beaker. Mortality was significantly reduced in the 10 ppt salinity treatment (P < 0.01) and showed a general trend of increasing mortality with decreased salinity. Settlement was the sum of both settled and metamorphosed larvae and showed a general trend of decreasing rates of settlement with decreased salinity. Settlement was significantly reduced in the 10 ppt salinity treatment (P < 0.01) but had greater variability between trials than mortality rates. Mortality ranged from 2-100% and settlement ranged from 0-89%.


RELATIONSHIP BETWEEN TEMPERATURE TRENDS AND THE TEMPORAL CHANGES IN THE LARVAL RECRUITMENT OF A NON-NATIVE CRUSTACEAN ALONG THE LEADING EDGE OF ITS RANGE

Popp, T (GPMB, University of Charleston, SC)

The non-native porcelain crab, Petrolisthes armatus, was first seen on intertidal oyster reefs in South Carolina in 1995.  Since then, its range is theorized to have expanded north in a series of surges and setbacks, where particularly cold winters may cause mortality in the northernmost populations. While P. armatus has occurred along the coast of South Carolina for nearly thirty years, relatively little is known about its reproductive biology and ecological impacts in its introduced range. Petrolisthes armatus reproduces year-round in the native range whereas its reproductive season in the novel range is limited to warmer months.  Variation in the timing and duration of larval recruitment are not known for the introduced range and these factors may affect further range expansion. My research examines whether P. armatus larval recruitment is related to temperature variation, in particular, the severity of winter temperatures. Biweekly larval tows collected in the North-Inlet Winyah Bay National Estuarine Research Reserve since 1981 provide a valuable resource for assessing P. armatus recruitment trends. I analyzed samples collected from 1994 to 2018 to determine whether the timing and duration of larval ingress varied over time and was related to temperature variation. Petrolisthes armatus larvae reached the region in 1995 and once established, has been present every year since. Results also show trends within the reproductive season that correlate with winter and spring temperature lows which will aid in understanding how this species will expand its range north.


DETERMINING POTENTIAL WATER QUALITY THREATS TO ACROPORA PALMATA REPRODUCTION AT SALT RIVER BAY NATIONAL HISTORIC PARK AND ECOLOGICAL PRESERVE IN ST. CROIX, USVI

Bayless, A (GPMB, University of Charleston, SC)

Acropora palmata (Elkhorn coral) was historically one of the most abundant reef building corals in the Caribbean, but they have declined more than 80% in the last 30 years. Surviving A. palmata in Salt River Bay National Historic Park and Ecological Preserve (SARI) in St. Croix, USVI have shown reproductive impairment with almost no gonadal material from tissue biopsies. In contrast, A. palmata from Buck Island Reef National Monument (BUIS), northeast of the St. Croix mainland, have a greater reproductive output at most sites. One hypothesis is that poor reproductive capability could be attributed to poor water quality in the vicinity of SARI. Sediment and coral skeletons were analyzed for trace elements using ICP-MS to examine potentially toxic metals and elemental proxies of water chemistry parameters. Most elements analyzed in the sediment were significantly higher in SARI, but the distribution of many elements was correlated with sediment grain size. In A. palmata skeletons only lead (42 ppb), zinc (3 ppm), and iron (8 ppm) were higher, while boron (63 ppm), barium (36 ppm), and phosphorus (50 ppm) were higher in BUIS skeletons. In a sea urchin embryo toxicity test, porewater from all SARI reef sites, which are outside of Salt River Bay, and all sites at BUIS caused abnormal development. However, porewater from many sites within Salt River Bay resulted in normally developed embryos. Salt River may not be the major source of poor water quality for A. palmata, and porewater near the colonies needs further evaluation for toxic compounds.


IMPROVING DIET RESOLUTION FOR LARGE REEF-ASSOCIATED PISCIVORES IN THE U.S. SOUTHEAST ATLANTIC USING MOLECULAR TOOLS

Spanik, K (GPMB, The University of Charleston, SC)

The importance of predator-prey interactions on marine fish populations has been recognized for quite some time. Since it is suggested that predation mortality rates often exceed fishing mortality rates, consideration in fisheries management is imperative. Diet studies are rapidly becoming a common practice of fisheries ecology, and are able to provide valuable insight on competition for resources, habitat use, energy flow, natural mortality, and seasonal variability that is essential for emerging ecosystem-based fishery management models. This type of information is especially important in South-Atlantic (SA) reef ecosystems, where many species exhibit high site-fidelity and spatial-overlap among multiple life history stages is common. Many large, piscivorous predators in the SA exhibit high digestion rates, and consequently their prey items are commonly unable to be visually confirmed through traditional morphological analysis techniques. This study employs DNA barcoding to provide more informative diet composition information for an assemblage of large, reef-associated, piscivorous predators from the SA. Since genomic DNA of prey items from stomach contents can be highly degraded, a portion of mitochondrial gene encoding the enzyme cytochrome oxidase subunit I was chosen as a target amplicon because of its abundance within cells, and publicly available primers and reference sequences that can be used to achieve species-level resolution. Both inter- and intra-specific composition was investigated using a suite of traditional metrics and potential influences of prey selection were explored using multi-variate analyses.


DETECTION OF MULTIPLE PATERNITY IN DIAMONDBACK TERRAPIN (MALACLEMYS TERRAPIN) EGG CLUTCHES FROM CHARLESTON, SC THROUGH THE USE OF NOVEL MOLECULAR TECHNIQUES

Sporre, M  (GPMB, The University of Charleston, SC)

In general, turtles do not exhibit strong social interactions that would give rise to multiple mating, nor do females receive direct benefits from having multiple mates. However, multiple paternity is commonly seen in turtle clutches. The degree of multiple paternity and clutch size are directly correlated to the probability of male encounters. Past studies of diamondback terrapins have shown variation in the occurrence of multiple paternity when under varying female dominated sex-ratios. Malaclemys terrapin, are a species of high priority conservation in South Carolina and, in the Charleston area, provide a good system to investigate the relationship between population sex-ratio and multiple paternity because of a high male to female sex-ratio. The presented portion of this project uses microsatellite markers to determine the frequency of multiple paternity from terrapin clutches collected in Charleston, SC. Results of this study will identify mating behaviors and effective population size of diamondback terrapins in the Charleston area while shedding light on the effects that sex-ratios have on the frequency of multiple paternity within conspecifics.


TIRE WEAR PARTICLES IN CHARLESTON HARBOR: ASSESSING THE FATE AND EFFECTS OF A STEALTHY SOURCE OF MICROPLASTICS

Kell, S  (GPMB, The University of Charleston, SC)

Studies conducted within the Charleston Harbor, SC watershed have revealed that >90% of total microplastics at some locations are tire wear particles (TWP).  Estimated annual U.S. TWP emissions are 1.6 x 106 tons, but little is known about the way by which they enter coastal waters and their potential effects on estuarine biota.  The objective of the present study is to determine the pathways by which microplastic debris, including TWP, enter Charleston Harbor and assess the toxicological consequences of TWP exposure to grass shrimp, Palaemonetes pugio.  Pathways will be assessed by sampling stormwater detention ponds (n=4) and adjacent receiving tidal waterbodies (at the discharge point, upstream 50 m, downstream 50 and 100 m). Laboratory exposures of TWP to adult grass shrimp will be used to quantify their residence time in the digestive tract and gills and assess any acute effects.  Preliminary results suggest that stormwater runoff and ponds are an important pathway for microplastics to adjacent waterways and that stormwater ponds may serve as a sink for microplastics. Abundances >62000 particles/m2 (2888 particles/kg ww), with TWP comprising 81% of the total, have been found in pond edge sediment.  Grass shrimp readily ingested and ventilated environmentally relevant sizes of TWP. TWP were retained for a longer period in the gut (avg. 45-65 hrs) than gills (avg. 25 hrs).  The results of this study will help increase awareness of TWP as a source of microplastics in coastal waterways, fill in existing knowledge gaps and help make better informed stormwater management decisions.  


AGE, GROWTH, AND REPRODUCTIVE LIFE HISTORY OF TWO DATA-DEFICIENT PARROTFISH SPECIES IN THE CARIBBEAN

Wagner, G  (GPMB, The University of Charleston, SC)

The grazing behavior of parrotfishes helps control algal growth and prevents coral reefs from becoming algae-dominated. No other organism provides this service; therefore the presence of parrotfishes is crucial to coral reef health. In the Caribbean, snapper and grouper species are commercially targeted, while parrotfishes have historically constituted a small, subsistence based fishery. In recent years, snappers and groupers have been heavily overfished, resulting in parrotfishes experiencing intense increases in fishing pressures. In 2011, the SouthEast Data, Assessment, and Review (SEDAR) stock assessment indicated severe data deficiencies regarding age, growth and reproductive biology of several parrotfish species, including redtail parrotfish Sparisoma chrysopterum and stoplight parrotfish Sparisoma viride, the two most heavily targeted parrotfish species in the Caribbean. Due to the severe lack of data, responsible management decisions were not possible. This study is filling data gaps by utilizing ages determined from otoliths, and reproductive maturities determined from reproductive histology. Combining these data results in growth rates, population age structure, sex ratios, reproductive seasonality, and size- and age-at-maturity and transition for redtail and stoplight parrotfish in Puerto Rico, St. Thomas, and St. Croix. Preliminary results suggest that both species exhibit year-round spawning, with large numbers of individuals developing or actively spawning in every month. Additionally, differences in age structure across islands may reflect differences in the commercial fisheries of each island.  The results of this study can influence management decisions such as catch limits, size and seasonality restrictions, as well as gear restrictions in order to better manage these species in a region where fisheries data are sparse.


A LIPIDOMIC APPROACH TO IDENTIFYING IMMUNE RESPONSE IN CETACEAN SKIN TO THE ATTACHMENT OF THE TASSEL BARNACLE, XENOBALANUS GLOBICIPTIS

Hall, A  (GPMB, The University of Charleston, SC)

The pseudo-stalked tassel barnacle, Xenobalanus globicipitis is an obligate commensal of cetaceans predominantly attaching to the fins and flippers of dolphins and other small whales in tropical and subtropical waters around the world. The life cycle and natural history of this species is little known as it occurs only sporadically across cetacean hosts making it difficult to study. This research explores the potential immune response of cetacean skin and plasma that may be induced by settlement of this barnacle. Plasma and non-invasive skin stripping discs collected from live dolphins during a health assessment in Sarasota, FL were extracted using traditional and novel lipid extraction techniques, respectively. The extracted samples were processed using an untargeted LC-MS/MS approach in positive, negative, and full scan modes and a list of lipids present was compiled for each sample using LipidMatchFlow software. These lipid profiles will be assembled and compared between groups of dolphins with and without X. globicipitis attached during health screenings. Lipid profiles will be analyzed using a principal component analysis (PCA) and significant lipids potentially associated with an immune response will be identified. Any significant differences in lipid profiles of animals with and without barnacles attached would be indicative of a potential new health risk for dolphin populations and could open the door for further cetacean immunology studies.


STRESS RESPONSE AND POST-RELEASE SURVIVAL OF BLACKTIP SHARKS (CARCHARHINUS LIMBATUS) CAPTURED IN SHORE-BASED AND CHARTER RECREATIONAL FISHERIES

Weber, N  (GPMB, The University of Charleston, SC)

In recent decades, the number of recreational fishermen has increased, including those participating in shore-based and charter fishing. The stress imposed on a fish through capture, and associated post-release survival rates, are poorly understood for most marine species. In the U.S. south Atlantic, the blacktip shark (Carcharhinus limbatus) is the most commonly landed large coastal shark species, and is targeted by both shore-based and charter fishermen. Despite its popularity, the effects of recreational capture and release on the blacktip shark are unknown. The present study aims to: (1) assess post-release survival rates of blacktip sharks captured in shore-based and charter fisheries; and (2) quantify the stress response associated with both recreational capture modes. To monitor post-release survival, sharks are fitted with acoustic transmitters and pop-up satellite tags. To quantify the stress response, blood is drawn via caudal venipuncture and analyzed for pH, lactate, hematocrit, plasma electrolytes (Na+, Cl, Ca2+, K+), and the concentration of a heat shock protein (Hsp70). Preliminary data indicate that pH, lactate (mmol/L), and hematocrit (%) do not differ between the two capture modes (p>0.05). However, as fight time increases, pH decreases (p<0.01) and lactate increases (p<0.001) for sharks caught both from shore and from charter boats. Additionally, hematocrit increases as fight time increases for sharks caught from shore (p<0.01). The present study will enhance our understanding of the blacktip shark’s physiological response to two different recreational capture modes and will provide post-release survival estimates critical to the upcoming stock assessment of the blacktip shark.


ATLANTIC DEEPWATER CANYONS: EXPLORATION AND RESEARCH OF SUBMARINE CANYONS OF THE WESTERN ATLANTIC MARGIN

Brooke, Sandra (Associate Researcher, Coastal and Marine Laboratory, Florida State University)

Submarine canyons are massive geological features that funnel currents and nutrients between the continental shelf and abyssal plane. Deep-sea canyons are dark, turbid and cold with strong currents that scour sediments to expose the underlying rocks, which are colonized by extensive communities of deep sea corals and their associates. There are many submarine canyons along the US east coast, and few have been explored. The Atlantic Deepwater Canyons project was a multidisciplinary study of two canyons in the US Mid-Atlantic region. Remotely Operated Vehicles revealed complex and diverse benthic communities on the canyon walls, including new species and several range extensions. This presentation will show the results of exploration and research in these remarkable features, including the first descriptions of methane seep communities in the region, and discuss conservation measures for deep sea ecosystems.