Sheepshead (Archosargus probatocephalus) are a popular recreational fisheries species in the Gulf of Mexico. Unfortunately, the highest reported catch of this species occurs primarily during their reproductive period. As a result, fishers have expressed their concerns to management about a potential overharvest. This research attempts to fill in the biological gaps for Sheepshead in order to provide management with information that will ensure future successful management practices. The specific goals of this research are to: (1) examine the life history of Sheepshead in the northeastern Gulf of Mexico (NE GOM), (2) understand the prey composition and feeding habits during their reproductive period, (3) determine the distribution of spawning adults, and (4) assess the spatial and temporal changes in abundance and population demographics on offshore sites. Sheepshead were captured from three unique habitats (nearshore estuaries, Sikes Cut, and offshore reefs) from January 2016- April 2017 in the NE GOM. Sheepshead were sampled exclusively during their reproductive period, which is from January through May, using a variety of different fishing methods. Otoliths were removed, sectioned and aged for 224 individuals. Von Bertalanffy growth equations were fit to the length-at-age data from this region. Growth was found to be variable across their geographic range. Maximum asymptotic length (441mm) and growth rate (0.24) were consistent with previous studies in Florida. Average age of Sheepshead was much higher than in other regions of Florida, potentially due to habitat degradation and development in the regions like Tampa Bay compared to the lack of development along the NE GOM’s “Forgotten Coast”. Stomach and intestinal contents were removed, identified to the highest taxonomic level, and the volumes were enumerated to assess for fullness. Contents and stomach fullness were compared across habitats. Multidimensional scaling plots with presence absence transformation of Sheepshead stomach content data were created using a Bray–Curtis similarity matrix. A one-way ANOSIM showed no significant (p=0.79) difference in Sheepshead diet by habitat type. This suggested feeding habits overlapped across habitat type. This could be a result of (1) similar prey items across habitats, (2) movement between habitats, or (3) different digestion rates of hard-bodied organisms. Sheepshead exhibited proportionally more empty stomachs and lower fullness scores offshore. Feeding was less frequent on offshore reefs, which could be due to less prey, energy reserves from past feeding events, or more focus on spawning. Gonads were removed, weighed, and either macroscopically staged (males), or histologically staged (females). Gonadosomatic indices, spawning activity, and histological stage were compared across three habitat sites. A higher proportion of active and imminent spawning individuals were found on offshore reefs and at Sikes Cut. Nearshore habitats exhibited a low proportion of spawning activity. This suggested nearshore habitats were not preferred spawning habitats, possibly due to lower salinities which cause declines in fertilization success. Abundance was assessed monthly using submersible rotating video devices on the three offshore sites only. Abundance was found to significantly (p < 0.001) increased during Sheepshead spawning season. Abundance was also significantly different (p < 0.001) across reef site. This suggested formation of spawning aggregations that differed across a spatial scale. Population demographics were measured by using laser photogrammetry during early, middle, and late spawning season on the three offshore sites. Sheepshead demographics were found to change across spatial and temporal scales. Average size was significantly less (p = 0.01) on Two Dog Reefballs, suggesting spawning populations are different across a local region. Sheepshead were significantly larger (p = 0.04) during the middle of their spawning season. This could be an evolutionary adaption to maximize fertilization success during peak spawning season. Sheepshead stocks have remained stable over the past few decades in the SE US. However, with increased fishing pressure during their reproductive period, both fishers and management recognize the potential for future declines. Results and findings from this study will be used when making future regulation decisions for Sheepshead. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2017. / July 19, 2017. / Diet, Fisheries, Growth, Reproduction / Includes bibliographical references. / Sandra Brooke, Professor Co-Directing Thesis; Jeff Chanton, Professor Co-Directing Thesis; Markus Huettel, Committee Member; Amy Baco-Taylor, Committee Member.

LLocal climate influences sea turtle hatching and emergence success with climatic extremes affecting embryonic development and hatchling emergence. Thus, it is crucial to understand how different climatic variables affect hatchling output presently and explore how potential climate change may impact future hatchling output and population stability. This thesis examines the influences of six climatic variables (air and sea surface temperature, precipitation, humidity, wind speed, and solar radiation) on the hatchling output of the loggerhead sea turtle (Caretta caretta) for two distinct nesting populations: Southwest Atlantic Loggerhead Regional Management Unit, which nests in Brazil, and the Northern Gulf of Mexico Loggerhead Recovery Unit, which nest in North Florida, USA and is part of the Northwest Atlantic Loggerhead Recovery Management Unit. Additionally, this thesis explores how potential climate change may impact future hatchling output. The main drivers of hatchling output varied across populations, nesting regions, and beaches. In Brazil, air temperature and precipitation were found to be the main climatic drivers of hatchling output, whereas in North Florida as well as air temperature and precipitation, humidity was a significant climatic driver of hatchling output. Climate projections show air temperatures warming at all sites throughout the 21st century, while projections for precipitation and humidity varied regionally. Our projections indicate that by 2100, tropical nesting beaches (Bahia, Brazil) will experience declines in hatching success, while temperate regions (Espirito Santo and Rio de Janeiro, Brazil and North Florida) will experience increases in hatching success. This thesis highlights the need to assess the climatic drivers of hatchling output at a regional scale, especially in temperate areas, to better understand how projected climate change may impact populations and better inform management. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / April 12, 2018. / Brazil, Florida, marine turtle, moisture, reproductive output, temperate / Includes bibliographical references. / Mariana M. P. B. Fuentes, Professor Directing Thesis; Markus Huettel, Committee Member; Jeff Chanton, Committee Member.

by Kwok Cheong Chung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 258-284). / Abstract --- p.i / Acknowledgements --- p.iii / Contents --- p.v / List of Appendices --- p.x / List of Figures --- p.x / List of Tables --- p.xi / List of Plates --- p.xii / Chapter Chapter 1. --- Introduction: General Biology of the Pomacanthids / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Zoo-geographical Description of the Pomacanthids --- p.1 / Chapter 1.3 --- Habitat of the Pomacanthids --- p.3 / Chapter 1.4 --- Feeding habits in the Pomacanthidae --- p.5 / Chapter 1.5 --- Reproductive Biology of Pomacanthidae --- p.6 / Chapter 1.5.1 --- Social Organization of the Pomacanthids --- p.6 / Chapter 1.5.2 --- Sexual Dichromatism in the Pomacanthids --- p.10 / Chapter 1.5.2.1 --- Sexual Dichromatism --- p.10 / Chapter 1.5.2.2 --- Sex Size Dimorphism --- p.11 / Chapter 1.5.3 --- Spawning time and season of the pomacanthids --- p.11 / Chapter 1.5.4 --- Spawning behavior of the pomacanthids --- p.12 / Chapter 1.5.5 --- Early egg and larval development of the pomacanthids --- p.14 / Chapter 1.6 --- Pomacanthidae: juveniles --- p.15 / Chapter 1.7 --- Systematics of the pomacanthids --- p.16 / Chapter 1.7.1 --- Differences between Pomacanthidae and Chaetodontidae --- p.16 / Chapter 1.7.2 --- Systematics of the pomacanthids --- p.19 / Chapter 1.7.3 --- Controversy in systematics of the pomacanthids --- p.19 / Chapter 1.8 --- Theme --- p.21 / Chapter Chapter 2. --- Systematics of the Pomacanthids --- p.25 / Chapter 2.1 --- A Brief note on the Classification of the Pomacanthids --- p.26 / Chapter 2.2 --- Brief Notes on Pomacanthid Genera --- p.28 / Chapter 2.2.1 --- Subfamily Pomacanthinae --- p.28 / Chapter 2.2.2 --- Subfamily Holacanthinae --- p.29 / Chapter 2.3 --- Key to Subfamilies and Genera of the Family Pomacanthidae --- p.31 / Chapter 2.4 --- Description of the Species --- p.32 / Chapter 2.4.1 --- Meristic Formula --- p.32 / Chapter 2.4.2 --- Explanations of the Abbreviations in the Meristic Formula --- p.32 / Chapter 2.4.3 --- Species description --- p.33 / Subfamily Pomacanthinae --- p.33 / "Chaetodontoplus Bleeker,1876" --- p.33 / "Chaetodontoplus ballinae Whitley,1959" --- p.33 / "Chaetodontoplus caeruleopunctauts Yasuda and Tominaga,1976" --- p.33 / "Chaetodontoplus chrysocephalus Bleeker,1854" --- p.34 / "Chaetodontoplus conspicillatus (Waite, 1900)" --- p.34 / "Chaetodontoplus duboulayi (Gunther, 1867)" --- p.34 / "Chaetodontoplus melanosoma (Bleeker, 1853)" --- p.35 / "Chaetodontoplus meredithi Kuiter,1990" --- p.35 / Chaetodontoplus mesoleucus (Bloch，1787) --- p.36 / "Chaetodontoplus personifer (McCulloch, 1914)" --- p.36 / "Chaetodontoplus septentrionalis (Schlegel,1844)" --- p.37 / "Pomacanthus Lacepede,1803" --- p.37 / "Subgenus Arusetta Fraser-Brunner,1933" --- p.37 / "Pomacanthus asfur (Forsskal, 1775)" --- p.37 / "Subgenus Euxiphipops Fraser-Brunner,1934" --- p.38 / "Pomacanthus navarchus (Cuvier, 1831)" --- p.38 / "Pomacanthus sexstriatus (Cuvier, 1831)" --- p.39 / "Pomacanthus xanthometopon (Bleeker, 1853)" --- p.39 / "Subgenus Pomacanthodes Gill,1862" --- p.40 / "Pomacanthus annularis (Bloch, 1787)" --- p.40 / "Pomacanthus chrysurus (Cuvier, 1831)" --- p.41 / "Pomacanthus imperator (Bloch, 1787)" --- p.41 / "Pomacanthus maculosus (Forsskal, 1775)" --- p.42 / "Pomacanthus semicirculatus (Cuvier, 1831)" --- p.43 / "Pomacanthus striatus (Ruppell, 1835)" --- p.44 / "Pomacanthus zonipectus (Gill, 1862)" --- p.45 / "Subgenus Pomacanthus Lacepede,1803" --- p.46 / "Pomacanthus arcuatus (Linnaeus, 1758)" --- p.46 / "Pomacanthus paru (Bloch, 1787)" --- p.46 / Subfamily Holacanthinae --- p.47 / "Apolemichthys Fraser-Brunner,1933" --- p.47 / "Apolemichthys arcuatus (Gray, 1831)" --- p.47 / "Apolemichthys armitagei Smith,1955" --- p.47 / "Apolemichthys griffisi (Carlson and Taylor, 1981)" --- p.48 / "Apolemichthys guezei (Randall, 1978)" --- p.49 / "Apolemichthys kingi Heemstra,1984" --- p.50 / "Apolemichthys trimaculatus (Lacepede, in Cuvier, 1831)" --- p.50 / "Apolemichthys xanthopunctatus Burgess,1973" --- p.50 / "Apolemichthys xanthotis (Fraser-Brunner, 1950)" --- p.51 / "Apolemichthys xanthurus (Bennett, 1832)" --- p.51 / "Centropyge Kaup,1860" --- p.52 / "Subgenus Centropyge Kaup,1860" --- p.52 / "Centropyge aurantius Randall and Wass,1974" --- p.52 / "Centropyge bicolor (Bloch,1787)" --- p.52 / "Centropyge boylei Pyle and Randall,1992" --- p.53 / "Centropyge colini Smith-Vaniz and Randall,1974" --- p.53 / "Centropyge debelius Pyle,1990" --- p.54 / "Centropyge eibli Klausewitz,1963" --- p.54 / "Centropyge flavissimus (Cuvier, 1831)" --- p.55 / "Centropyge heraldi Woods and Schultz,1953" --- p.55 / "Centropyge multifasciatus (Smith and Radcliffe, 1911)" --- p.56 / "Centropyge narcosis Pyle and Randall,1993" --- p.57 / "Centropyge nox (Bleeker, 1853)" --- p.57 / "Centropyge tibicen (Cuvier, 1831)" --- p.58 / "Centropyge vrolicki (Bleeker, 1853)" --- p.58 / "Centropyge Kaup,1860" / "Subgenus Xiphipops Jordan and Jordan,1922" --- p.59 / "Centropyge acanthops (Norman, 1922)" --- p.59 / "Centropyge argi Woods and Kanazawa,1951" --- p.60 / "Centropyge aurantonotus Burgess,1974" --- p.60 / "Centropyge bispinosus (Gunther, 1860)" --- p.60 / "Centropyge ferrugatus Randall and Burgess,1972" --- p.61 / "Centropyge fisheri (Snyder, 1904)" --- p.61 / "Centropyge flavicauda Fraser-Brunner,1933" --- p.62 / "Centropyge flavipectoralis Randall and Klausewitz,1977" --- p.62 / "Centropyge hotumatua Randall and Caldwell,1973" --- p.63 / "Centropyge interruptus (Tanaka, 1918)" --- p.63 / "Centropyge joculator Smith-Vaniz and Randall,1974" --- p.64 / "Centropyge loriculus (Gunther, 1860)" --- p.64 / "Centropyge multicolor Randall and Wass,1974" --- p.65 / "Centropyge multispinis (Playfair, 1866)" --- p.65 / "Centropyge nahackyi Kosaki,1989" --- p.66 / "Centropyge nigriocellus Woods and Schultz,1953" --- p.66 / "Centropyge potteri Jordanand Metz,1912" --- p.67 / "Centropyge resplendens Lubbock and Sankey,1975" --- p.67 / "Centropyge shepardi Randall and Yasuda,1979" --- p.67 / "Genicanthus Swainson,1839" --- p.68 / "Genicanthus bellus Randall,1975" --- p.68 / "Genicanthus caudovittatus (Gunther, 1860)" --- p.69 / "Genicanthus lamarck (Lacepede, 1802)" --- p.69 / "Genicanthus melanospilos (Bleeker, 1857)" --- p.70 / "Genicanthus personatus Randall,1975" --- p.71 / "Genicanthus semicinctus (Waite, 1900)" --- p.71 / "Genicanthus semifasciatus (Kamohara, 1934)" --- p.72 / "Genicanthus spinus Randall,1975" --- p.73 / "Genicanthus watanabei (Yasuda and Tominaga, 1970)" --- p.73 / "Holacanthus Ldcepede,1803" --- p.74 / "Subgenus Angelichthys Jordan and Evermann,1895" --- p.74 / "Holacanthus africanus Cadenat,1950" --- p.74 / "Holacanthus bermudensis Jordan and Rutter,1898" --- p.74 / "Holacanthus ciliaris (Linnaeus, 1758)" --- p.75 / "Subgenus Holacanthus Lacepede,1803" --- p.76 / "Holacanthus tricolor (Bloch, 1795)" --- p.76 / "Subgenus Plitops Fraser-Brunner,1933" --- p.77 / "Holacanthus clarionensis Gilbert,1890" --- p.77 / "Holacanthus limbaughi Baldwin,1963" --- p.77 / "Holacanthus passer Valenciennes,1846" --- p.77 / Subgenus undetermined --- p.78 / "Holacanthus venustus Yasuda and Tominaga,1969" --- p.78 / "Pygoplites Fraser-Brunner,1933" --- p.79 / "Pygoplites diacanthus (Boddaert, 1772)" --- p.79 / Chapter 2.5 --- Natural Hybrids in Family Pomacanthidae --- p.79 / Chapter Chapter 3. --- Age and Growth of the Pomacanthids --- p.82 / Chapter 3.1 --- Introduction --- p.82 / Chapter 3.2 --- Age Determination --- p.83 / Chapter 3.21 --- Peterson's Method --- p.84 / Chapter 3.22 --- Scale as Aging Structures --- p.84 / Chapter 3.23 --- Otolith as Aging Structures --- p.87 / Chapter 3.24 --- Other Structures in Aging of Fish --- p.89 / Chapter 3.25 --- Tagging of Fish in Age Determination --- p.89 / Chapter 3.3 --- Growth --- p.90 / Chapter 3.4 --- Mathematical Models of growth --- p.92 / Chapter 3.41 --- The von Bertalanffy Growth Model --- p.92 / Chapter 3.42 --- The Logistic Equation --- p.93 / Chapter 3.43 --- Compertz Growth Curve --- p.93 / Chapter 3.44 --- Parker and Larkin Growth Curve --- p.93 / Chapter 3.5 --- Materials and Methods --- p.94 / Chapter 3.51 --- Fish Specimens --- p.94 / Chapter 3.52 --- Relationship between Standard Length and Body Weight --- p.94 / Chapter 3.53 --- Preparation of Scales for Annulus Estimation --- p.95 / Chapter 3.54 --- Scale Measurements --- p.95 / Chapter 3.55 --- Marginal Growth Index --- p.98 / Chapter 3.56 --- Estimation of the von Bertalanffy Parameters --- p.98 / Chapter 3.6 --- Results and Discussion --- p.98 / Chapter 3.6.1 --- The Scales --- p.98 / Chapter 3.6.2 --- Relation between Standard Length and Scale Length --- p.98 / Chapter 3.6.3 --- Relation between Standard Length and Sex --- p.99 / Chapter 3.6.4 --- Relation between Standard Length and Body Weight --- p.104 / Chapter 3.6.5 --- Back Calculated Standard Lengths at Different Ages --- p.110 / Chapter 3.6.6 --- Marginal Growth Increment --- p.112 / Chapter 3.6.7 --- Relation between Standard Length and Preopercular Spine Length --- p.112 / Chapter 3.6.8 --- Fulton's Condition Factor and Modified Fulton's Condition Factor --- p.112 / Chapter 3.6.9 --- Growth Index --- p.118 / Chapter 3.6.10 --- The von Bertalanffy Parameters --- p.121 / Chapter 3.7 --- Discussion --- p.128 / Chapter Chapter 4 --- . Studies on Isozymes of the Pomacanthidae --- p.132 / Chapter 4.1 --- Different Approaches of Systematics --- p.132 / Chapter 4.1.1 --- Phenetic Analysis --- p.132 / Chapter 4.1.2 --- Cladistics Analysis --- p.133 / Chapter 4.2 --- An Overview on Biochemical and Molecular Systematics --- p.135 / Chapter 4.2.1 --- Biochemical Systematics --- p.135 / Chapter 4.2.2 --- Molecular Systematics --- p.136 / Chapter 4.2.2.1 --- Nucleic Acid Hybridization --- p.136 / Chapter 4.2.2.2 --- Restriction-site and Sequencing Analysis --- p.137 / Chapter 4.3 --- Isozyme Electrophoresis --- p.137 / Chapter 4.3.1 --- Isozyme Electrophoresis in Population Genetics --- p.140 / Chapter 4.3.2 --- Isozyme Electrophoresis in Phylogenetic Analysis --- p.141 / Chapter 4.3.3 --- Standard Procedures in Treatment of Allozyme Data --- p.142 / Chapter 4.3.3.1 --- Interpreting Electromorphs on Gels --- p.142 / Chapter 4.3.3.2 --- Allele Frequency --- p.144 / Chapter 4.3.3.3 --- Genetic Distances --- p.144 / Chapter 4.3.3.4 --- Clustering --- p.145 / Chapter 4.4 --- Taxonomy of the Pomacanthidae --- p.146 / Chapter 4.5 --- Materials and Methods --- p.147 / Chapter 4.5.1 --- Pomacanthid Species under Investigation --- p.147 / Chapter 4.5.2 --- Allozymes Investigated --- p.149 / Chapter 4.5.3 --- Sample preparation for electrophoresis --- p.149 / Chapter 4.5.4 --- Chemicals and Buffers --- p.149 / Chapter 4.5.5 --- Preparation of Starch Gels --- p.151 / Chapter 4.5.6 --- Sample Loading --- p.151 / Chapter 4.5.7 --- Electrophoresis --- p.155 / Chapter 4.5.8 --- Gel Slicing --- p.155 / Chapter 4.5.9 --- Gel Staining --- p.156 / Chapter 4.5.10 --- Gel Scoring and Data Analysis --- p.157 / Chapter 4.5.11 --- Comparison between Taxa --- p.158 / Chapter 4.6 --- Results and Discussions --- p.160 / Chapter 4.6.1 --- Summary of the Loci Scored --- p.160 / Chapter 4.6.2 --- Genetic Variability of the Scored Loci --- p.161 / Chapter 4.6.3 --- Allele Frequencies --- p.163 / Chapter 4.6.4 --- Genetic Distance between Taxa --- p.186 / Chapter 4.6.5 --- Genetic Distance between Genera and Subgenera --- p.186 / Chapter 4.6.6 --- Phenetic Dendrograms of the 31 Pomacanthid Species Investigated --- p.191 / Chapter 4.6.7 --- Discussions --- p.194 / Chapter 4.6.7.1 --- Tertiary Structure of the Enzymes Scored --- p.194 / Chapter 4.6.7.2 --- Number of Specimens examined per Species --- p.194 / Chapter 4.6.7.3 --- Average Heterozygosity --- p.195 / Chapter 4.6.7.4 --- Genetic Distances among the Pomacanthids --- p.197 / Chapter 4.6.7.5 --- Phylogenetics of the Pomacanthids as revealed from Isozyme Electrophoresis --- p.198 / Chapter Chapter 5 --- Conclusions --- p.205 / Appendices --- p.210-257 / Bibliography --- p.258-284 / List of Appendices: / Appendix A. Geographical distribution of individual pomacanthid species --- p.210-213 / Appendix B. List of locations of the geographic names --- p.214-215 / Appendix C. Full names of the references listed in the taxonomic part of the text --- p.216-219 / Appendix D. (1) Computer program modified from Cao (1988) for calculating the von Bertalanffy parameters --- p.220-226 / Chapter (2) --- Modified Version of the computer program (GENDIST) for calculating Genetic Distance (Corrected for small Sample Size) --- p.227-237 / Appendix E. A summary of the Staining Methods employed --- p.238-240 / Appendix F. Morphology and Color Pattern of the pomacanthid species investigated in allozyme electrophoresis --- p.241-257 / List of Figures / Figure 3.1 The Position of Sampling scales from Pomacanthid Specimens --- p.96 / Figure 3.2 Relation between Standard Length and Scale Length of Pomacanthus imperator --- p.103 / Figure 3.3 Relation between Age and Standard Length of Pomacanthus imperator --- p.106 / Figure 3.4 Relation between Age and Body Weight of Pomacanthus imperator --- p.107 / Figure 3.5 Relation between Standard Length and Body Weight of Pomacanthus imperator - Cubic Polynomial Regression --- p.108 / Figure 3.6 Relation between Standard Length and Body Weight of Pomacanthus imperator - Logistic Regression --- p.109 / Figure 3.7 Walford Plot on The Growth of Pomacanthus imperator --- p.111 / Figure 3.8 Annual Marginal Increments in Scales of Pomacanthus imperator --- p.114 / Figure 3.9 Relation between Standard Length and Preopercular Spine Length of Pomacanthus imperator --- p.115 / Figure 3.10 Change in Fulton's Condition Factor with Age in Pomacanthus imperator --- p.116 / Figure 3.11 Change in Modified Fulton's Condition Factor with Agein Pomacanthus imperator --- p.117 / Figure 3.12 Change in Growth Index with Age in Pomacanthus imperator --- p.120 / Figure 3.13 von Bertalanffy Growth Curve for Standard Length of Pomacanthus imperator --- p.122 / Figure 3.14 von Bertalanffy Growth Curve for Body Length of

Although more than 1300 marine reserves have already been established around the world, they still present a relatively new tool for environmental conservation and fisheries management. In accordance with this new approach towards marine protection, conservationists currently call for rapid establishment of a reserve network, which would encompass 10% to 30% of the oceans. Representative habitats from coastal areas as well as high seas would be included. Such a network should serve as a haven for marine species, ensuring their sustainability and aiding them to recover from fishery pressure. Furthermore, reserves are expected to enhance yields to the fishing industry through spillover and larval export. The paper attempts to determine, whether and under which conditions do marine reserves bring net benefits to economies.

Long-term bioaccumulation studies were conducted using ('14)C-Kepone and unlabeled Kepone to determine the significance of dietary accumulation to final Kepone body burdens in spot (Leiostomus xanthurus) and grass shrimp (Palaemonetes pugio). Both food (grass shrimp) and consumer organisms were exposed to aqueous Kepone concentrations of 0.04 (mu)g/l at 23�C for 16-19 days, followed by a 21-28 day clearance phase. Dietary and aqueous sources of Kepone were shown to be additive for both species. Dietary contributions of Kepone represented 9, 18 and 38% of the total Kepone body burden in spot fed contaminated food rations of 4, 8 and 20% mean body weight, respectively. at rations of 4 and 8%, dietary Kepone contributions to final shrimp body burdens were 24 and 33%, respectively. There were no significant differences in organism size or lipid content among treatments for either species. Ration size had no effect in either organism on the uptake and clearance rate constants estimated for dietary accumulation and bioconcentration by a first-order pharmacokinetic model. Shrimp had a slower clearance rate of Kepone than spot and, hence, a greater bioaccumulation potential. Kepone derived from aqueous exposures to both species appeared to be cleared more slowly than residues derived from dietary exposure. Kepone assimilation efficiencies for spot and shrimp were 15% and 21%, respectively, for the finely ground food source used in this study. These values are low compared to literature data for other lipophilic chlorinated hydrocarbons. This indicates that grinding of the food reduced Kepone availability to the consumer organisms. Event at these low assimilation efficiencies, Kepone from the diet contributed significantly to final Kepone body burdens in spot and shrimp. An accelerated test methodology was adequate to describe spot bioaccumulation kinetics, especially at the larger food ration size tested. Uptake of Kepone from contaminated artificial food was similar to uptake from contaminated natural food.

Macoma balthica is a Tellinid bivalve that is common to both marine and estuarine soft-bottom habitats of the northern hemisphere. to determine if populations on the eastern and western North Atlantic are conspecific, the labial palp morphology, shell shape and genetic composition of these populations were examined. Previously described differences in the labial palp morphology do not occur among the population investigated. Differences in the shell shape and genetic composition, determined by enzyme electrophoresis, were observed between populations from the eastern and western North Atlantic. Allopatric populations of Macoma balthica from the eastern and western North Atlantic can be considered as separate and sibling species.

Distribution patterns of the Atlantic menhaden Brevoortia tyrannus) have been evaluated in respect to the feeding ecology of the species. Feeding experiments, functional morphology, and field distribution studies with young postmetamorphic fish were conducted to differentiate the feeding dynamics of different size menhaden, and to define the relationship between feeding and distribution. Feeding experiments were conducted with 138 mm fork length menhaden to determine their particle size-specific feeding abilities. The minimum size of particles filtered, the minimum size threshold, was 7 to 9 (mu)m. Phytoplankton larger than the minimum size threshold and smaller than 20 (mu)m upper limit for nanoplankton, were filtered at efficiencies averaging 21% (n = 24). Prey particles exceeding the size limits of nanoplankton, were filtered at average efficiencies ranging from 22% to 84%. The mean filtration efficiency for Artemia sp. nauplii of 36% (n = 7) was lower than for smaller phytoplankton prey. as menhaden grown, their feeding repertoire shifts to larger planktonic organism. Surface ultrastructure, epithelial organization, and gross morphology of the branchial basket in menhaden were analyzed with respect to food particle capture, transport of food from the point of capture to point of ingestion, and potential gustatory reception. Branchiospinules, sites of small particle capture, lacked mucous cells, suggesting that food is captured primarily by mechanical sieving. Taste buds on the glossohyal are thought to be mechanoreceptors, whereas taste buds on the crest of the fifth branchial arch are thought to be chemoreceptors. Concurrent synoptic observation of the relative abundance of menhaden and parameters relevant to characterizing primary production along transects in estuarine creek ecosystems have been used to interpret the factors governing the fishes' local distribution. The strongest associations were between catch and chlorophyll-a, catch and microflagellates, and catch and diatoms. Fish often distributed with a gradient of one phytoplankton taxa over another based on selectivity for large phytoplankton cell size. Menhaden are optimal foragers displaying kinesis selecting for areas of optimally sized prey, chemosensory preference for plant versus detrital particles, and possibly taxa specific avoidance. Comparison of latitudinal distribution patterns of menhaden with the latitudinal trends in plankton community size frequency suggest that fish stratify by size at latitude to maximize the efficiency with which they filter-feed.

The macrobenthic invertebrates of the North Carolina continental shelf in the vicinity of Cape Hatteras were sampled during four seasonal cruises, June 1977 to January 1978. Macrobenthos-sediment relationships were investigated in the area surrounding Diamond Shoals. Four benthic assemblages were recognized, each representative of specific sediment regimes. The results of multivariate analyses were interpreted as indicating that the percentages of very fine sand and silt and clay were of greatest biological significance. It is suggested that the importance of finer particles is due to their influence on sediment permeability and organic content. The degree of particle sorting was also important in accounting for some faunal differences with fossorial species predominating in the most well-sorted sediments. Thermal factors were found to be the dominating factor in species distributions on the shelf north of Cape Hatteras, an area occupied by a sharp thermal front between Gulf Stream and Virginia Shelf Water. The benthic community exposed to the greatest thermal variability within the front was more speciose than the benthos of more thermally stable areas, but otherwise demonstrated no unique characteristics. For several species the front represented a zoogeographic barrier. at mid-shelf depths the Cape Hatteras region was far more effective in limiting the northward distribution of southern species than in limiting the southward distribution of northern species. Biogeographic affinities, extent of geographic range, and ability to traverse the Cape Hatteras area were compared among the four most speciose groups, the Polychaeta, Amphipoda, Bivalvia and Gastropoda. The polychaetes and amphipods exhibited the broadest geographic distributions while the molluscs, particularly the gastropods, were the most narrowly distributed. These differences are related to the dispersal capabilities and comparative degree of eurytopy among the four macrofaunal groups considered. The present-day distributions and biogeographic affinities of the North Carolina macrofauna are also a function of the geologic history of the northwestern Atlantic and the evolutionary origin of the fauna.

In order to assess the secondary production potential of the amphipod Gammarus mucronatus its life history was examined with laboratory experimentation and field sampling in two warm temperate estuarine habitats in the York River, Virginia. A seagrass (Zostera marina) bed and a macroalgae (Ulva spp., Enteromorpha spp.) fouling community on old pier pilings. Variations in amphipod abundance between the habitats were not similar. G. mucronatus was present in the seagrass habitat during most of the year attaining maximum densities of 1200(.)m('-2) in the spring. Presence of G. mucronatus in the macroalgae habitat was almost totally restricted to late spring and early summer, but maximum densities as high as 6800(.)m('-2) occurred. Estimates from field and laboratory evidence suggest that G. mucronatus produced 6-9 generations over a one year period. Rapid turnover resulted from increased spring and summer growth rates and maturation at smaller sizes during these months. Reduction in size of summer adults is hypothesized to be a co-evolutionary response to predation by which the amphipod population can increase its intrinsic rate of growth (r). Production calculations were made using four different approaches. The size-frequency method was calculated for 26 fortnightly sample dates, two alternate subsets of the data set (13 sample dates each), and separate calculations for the sexes. The fourth approach utilized a modified instantaneous growth (IGR) equation. The IGR method produced results that were more than 25% greater than the size-frequency estimates which all agreed fairly well. Monthly sampling is sufficient to characterize the population for production estimates, but because of rapid spring and summer growth it is incapable of detecting voltinism. Production in the algal habitat was 10.2 g m('-2)(.)yr('-1) with a P/B of 60.8, greater than the 5.0 g m('-2)(.)yr('-1) production and 40.0 P/B of the seagrass habitat. The higher algal values are the result of the greater maximum abundance of this habitat coinciding with rapid spring and summer growth. of three different predictive models tested, one proposed by Robertson (1979) provides the best agreement with the P/B estimates calculated from empirical data.

An analytical technique was developed to measure adenine nucleotide levels (ATP, ADP, AMP) and adenylate energy charge (EC) in Zostera marina (eelgrass), a submerged marine angiosperm. A tissue comparison and seasonal survey provide baseline information on natural adenylate variability. The methodology developed can be suitably adapted to other macrophyte species as well. Plants were frozen, lyophilized, scraped free of epiphytes, and homogenized. Adenylates were extracted with boiling 1 mM EDTA + 5% (w/v) PVPP (pH 7.6), and assayed by enzymic conversion of AMP and ADP to ATP, followed by quantitative analysis of ATP via the firefly bioluminescent reaction. ATP, ADP, total adenylates (AT), and EC were highest in leaf tissue (photophosphorylating source), while all adenylates were lowest in root plus rhizome. Monthly time series with aboveground tissue show ATP concentration highest in August and lowest in April, corresponding to periods of senescence (decreased ATP utilization) and growth (increased ATP utilization), respectively. Response of adenine nucleotides and EC in Z. marina to nutrient enrichment, light reduction, and herbicide (atrazine) exposure was evaluated as a monitor of metabolic state. Nutrient enrichment over 2 weeks increased epiphyte colonization, which in turn, appeared to negatively impact Z. marina adenylate content, net productivity, and growth. Z. marina ATP, AT, and EC were weakly and positively correlated with nutrients and light, but decreased over time. Short-term (6 hr) atrazine stress reduced ATP and AT at both 10 and 100 ppb, but EC remained constant. Net productivity decreased at 100, but not at 10 ppb atrazine over 6 hrs. Long-term (21 day) atrazine stress was evident from growth inhibition and 50% mortality near 100 ppb. EC was reduced at 0.1, 1.0, and 10 ppb atrazine, but ATP and EC increased with physiological adaptation to severe stress (100 ppb) after 21 days. Apparently, ATP and AT decrease over the short-term but rebound over the long-term with severe atrazine stress, increasing beyond control levels before plant death results. Supplementing adenine nucleotide and EC results with more conventional quantitative analyses would afford greater knowledge of physiological response to environmental variation.