Digital Commons Network^™

Channeled Whelk (Busycotypus Canaliculatus) Ecology In Relation To The Fishery In Vineyard And Nantucket Sounds, Massachusetts, Shelley Ann Edmundson

Doctoral Dissertations

Channeled whelks (Busycotypus canaliculatus) are predatory marine gastropods that support lucrative commercial fisheries along the east coast of the United States, with areas around Massachusetts supplying the largest landings. In the absence of a more thorough and comprehensive understanding of channeled whelk biology, it is unclear how to sustainably manage their fisheries. Within this dissertation, various aspects of whelk ecology were investigated to determine how to protect this species, while effectively managing the local fishery.

Early life history experiments revealed channeled whelk egg strings may incubate for 8 to 9 months in MA water temperatures. Incubation period decreased with increasing …

Characterization Of The Prokaryotic Community Associated With The Giant Barrel Sponge, Xestospongia Muta Across The Caribbean, Cara L. Fiore

Doctoral Dissertations

Sponges have long been known to be ecologically important members of the benthic fauna on coral reefs. Recently, it has been shown that sponges, and their symbiotic microbes, are also important contributors to the nitrogen biogeochemistry of coral reefs. Here, I investigate the ecology and physiology of the microbial community associated the ecologically dominant sponge, Xestospongia muta. A natural experiment was conducted with X. muta form three different locations (Florida Keys, USA; Lee Stocking Island, Bahamas, and Little Cayman, Cayman Islands) to compare nitrogen cycling and prokaryotic community composition. The dissolved inorganic nitrogen (DIN) fluxes of sponges were studied using …

The Effects Of Biotic And Abiotic Factors On Byssogenesis, Growth And Movement Patterns Of The Blue Mussel, Mytilus Edulis, Yvette Louise Garner

Doctoral Dissertations

Blue mussels create extensive aggregations on intertidal and low subtidal shores in the Gulf of Maine, in which they modify habitat, trap sediments and create microclimates for many organisms. Mussels are an important aquaculture species worldwide, and play a major part of the economy of New England. Blue mussels produce collagenous byssal threads to anchor themselves to the substrate on wave swept shores. Byssogenesis, growth and movement abilities of mussels are influenced by a host of biotic and abiotic factors. In this dissertation I quantified byssogenesis and growth of the blue mussel, Mytilus edulis, affected by wave exposure, temperature, and …

Movements, Dive Behavior And Trophic Ecology Of Leatherback Turtles (Dermochelys Coriacea) In The Northwest Atlantic, Kara Dodge

Doctoral Dissertations

The endangered leatherback turtle is a highly migratory predator that feeds exclusively on gelatinous zooplankton. Leatherbacks spend most of their lives submerged or offshore, and their at-sea biology (particularly that of males and sub-adults) is poorly understood throughout much of their range. I used satellite telemetry to monitor movements and dive behavior of nine adult and eleven sub-adult leatherbacks captured off Massachusetts, USA, and tracked throughout the NW Atlantic. Leatherback movements and environmental associations varied by oceanographic region, with slow, sinuous, area-restricted search behavior and shorter, shallower dives occurring in cool, productive, shallow shelf habitat at temperate latitudes. Leatherbacks were …

The Impact Of Seasonal Movements By Ovigerous American Lobsters (Homarus Americanus) On Egg Development And Larval Release, Jason Seth Goldstein

Doctoral Dissertations

The American lobster (Homarus americanus) supports one of the most economically successful fisheries in the Gulf of Maine. The continued success of this fishery is attributed in part to vigilant broodstock conservation through the preservation of ovigerous (egg-bearing) females. Previous studies of ovigerous lobster movements indicate that some, if not most, display seasonal inshore-to-offshore movement patterns. While it has been assumed that these movements serve to expose eggs to thermal regimes that are optimal for development, this theory has never been rigorously tested. In Chapter 1, I present results from ultrasonic tracking studies designed to determine if lobsters in coastal …

An Investigation Of Non-Spatial Cognitive Abilities In An Asocial Corvid, The Clark's Nutcracker (Nucifraga Columbiana), Jan K. Tornick

Doctoral Dissertations

A great deal of research suggests that the cognitive abilities of birds in the family Corvidae (crows and jays) are comparable in many aspects to that of apes. Scientists have posited competing hypotheses to explain how complex cognitive abilities arise in a species or group of animals. One such hypothesis, the social-intelligence hypothesis, states that the demands of living in a large, dynamic group drive an animal's need for complex cognitive skills. The ecological-intelligence hypothesis, predicts that generalist foragers develop more highly flexible behaviors and a wider cognitive repertoire than specialist foragers. To date, cognitive research on corvids has focused …

Flatfish Stock Enhancement: Examining Conditioning Strategies To Promote Success, Michelle Lynn Walsh

Doctoral Dissertations

Conditioning is the process of providing individuals reared for stock enhancement with some degree of "wild" experience prior to release. Flatfish trained for "wild" conditions may more easily and successfully transition to natural environments. This dissertation identifies strategies that optimize feeding-related performance of flatfish in the hatchery and subsequently post release in the wild.

The influence of live feed conditioning on feeding performance of juvenile winter flounder, Pseudopleuronectes americanus, was investigated. In the hatchery, fish reared on live feeds exhibited significantly higher survival (P < 0.0001) and growth (P < 0.01) than those reared on formulated feed. Once released into cages in the wild, amphipodreared fish had higher mean Stomach Contents Index and RNA/DNA of all feed types, including wild fish. Wild and worm-reared fish exhibited the most similar survival, baseline RNA/DNA values, overall stomach fullness, and diet composition profiles over time.

Pre-release, experimental cage conditioning was conducted for stocking Japanese flounder, Paralichthys olivaceus, in Wakasa Bay, Japan. …

The Use Of Multibeam And Split-Beam Echo Sounders For Assessing Biomass And Distribution Of Spring-Spawning Atlantic Cod In The Gulf Of Maine, Christopher William Damon Gurshin

Doctoral Dissertations

This research focused on advancing the application of split-beam and multibeam echo sounding to remotely locate and describe spatial distribution, and to provide a relative measure of abundance of the spring-spawning Atlantic cod (Gadus morhua) in the western Gulf of Maine. Specifically, the main objectives of this research were 1) to test the feasibility of a multibeam echo sounder to detect changes in volume backscatter proportional to incrementally decreasing quantities of cod held in a submerged cage, and to compare results to a split-beam echo sounder; 2) to describe the spatio-temporal distribution and estimate biomass of spring-spawning cod in the …

Movement And Behavior Of Ocean Sunfish, Mola Mola, In The Northwest Atlantic, Inga F. Potter

Doctoral Dissertations

The ocean sunfish, Mola mola, has a worldwide distribution and is a common resident of the NW Atlantic Ocean. Notable for its unusual anatomy and large size, the biology of the species is largely unknown. I examined the movement and behavior of M. mola using pop-up satellite archival tags (PSAT's). In addition, analysis of aerial survey data was conducted to determine the distribution of ocean sunfish (Family Molidae) in NW Atlantic shelf waters. Data was analyzed from twenty-five PSAT's deployed on M. mola in the northwest Atlantic between 2005 and 2008. Tags were attached from 7-242 days. Results indicate that …

Comparative Embryology And Muscle Development Of Polyclad Flatworms (Platyhelminthes: Rhabditophora), Diana Marcela Bolanos

Doctoral Dissertations

Polyclads belong to the phylum Platyhelminthes, lineage Rhabdotophora, are simple Bilateria, and represent an interesting and useful group for research in developmental biology. Although polyclads, together with catenulids and macrostomids, have been argued to be most closely related to the ancestral flatworm and hold the key to understand the relationship between development and evolution, knowledge of their embryonic development is still scarce and most of the work on spiralian development has focused on mollusks and annelids. In view of polyclad embryonic significance, a comparative study of their embryonic development including several species of direct and indirect developers was performed.

Developing …

Systematics And Taxonomy Of Polyclad Flatworms With A Special Emphasis On The Morphology Of The Nervous System, Sigmer Y. Quiroga

Doctoral Dissertations

In a first survey of the Colombian polyclad fauna, a total of 25 species were collected from the rocky littoral of the Tayrona National Park, Santa Marta, Colombia and deposited at the Museo de Historia Natural Marina del INVEMAR. Six species represented first records for Caribbean region. Furthermore, a new combination Phrikoceros mopsus nov. comb, was proposed, and a possible new species of Pleioplana Faubel, 1983 was found. In addition, a new polyclad family Anocellidae was erected and four deep-sea species were described; two species from the North Pacific Ocean, Anocellidus profundus gen. nov. sp. nov. and Oligocladus voightae sp. …

Resolving The 150 Year Debate Over The Ecological History Of The Common Periwinkle Snail, Littorina Littorea, In Northeast North America, April M H Blakeslee

Doctoral Dissertations

Littorina littorea (common periwinkle snail) is highly abundant in both Europe and North America. A known native of Europe, its presence in North America has been the subject of a one-hundred year debate. Prior published work attempting to resolve its cryptogenic (=uncertain origin) status with historical, archaeological, ecological and/or genetic data were not successful. I therefore included novel parasite and molecular evidence to definitively resolve L. littorea's North American cryptogenic status.

First, I explored trematode species richness patterns in European versus North American L. littorea and two co-occurring native congeners, L. saxatilis and L. obtusata. Through extensive field and literature …

The Maintenance, Evolution, And Impacts Of Inducible Morphological Defenses In Mytilus Edulis: Responses To Multiple And Invasive Predators, Aaren Scott Freeman

Doctoral Dissertations

The burgeoning field of phenotypic plasticity and inducible defenses has documented a wide variety of predator-induced defenses. I this dissertation I have explored induced defenses in the marine mussel Mytilus edulis as they are affected by (a) shared evolutionary history with invasive crab predators, (b) specificity of responses to multiple predators (singly and combined) with different foraging strategies, and (c) spatial and temporal variation in the expression of predator specific induced defenses in situ.

Mytilus from southern New England expressed induced shell thickening when exposed to waterborne cues from the crab Hemigrapsus , but "naive" northern mussel populations do not …

Interactions Between Two Invasive Crab Predators, Carcinus Maenas And Hemigrapsus Sanguineus, And Consequences For The Native Community, Blaine David Griffen

Doctoral Dissertations

With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. As invasive species become more common, interactions between invasive species will also increase and may alter the way that these species impact invaded communities. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid 1800s and often has detrimental impacts on prey communities. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions …

Gonadal Histology And Reproductive Steroidogenesis Of Anurans Exposed To Potential Endocrine Disrupting Contaminants, Emily May La Fiandra

Doctoral Dissertations

The prevalence of malformed amphibians and the association of high incidences of malformation with the presence of environmental contaminants have raised questions about the effects of environmental contaminants on the development of larval amphibians. The potential endocrine disrupting effects of pesticides suggest that the reproductive and developmental abnormalities observed in larval anurans may be due at least in part to impacts on the hypothalamic-pituitary-gonadal axis. The present studies investigate the effects of exposure to environmental contaminants including DDT and atrazine on the development, gonadal histology and reproductive steroidogenesis of larval anurans.

As previous monitoring at Great Bay National Wildlife Refuge …

Cichlids As A Model For The Evolution Of Visual Sensitivity, Tyrone Clifford Spady

Doctoral Dissertations

The cichlid fishes of East Africa are the most ecologically diverse radiation of recent vertebrates. These highly visual fish live in habitats ranging from turbid rivers to clear lakes. They have evolved to exploit an astounding array of foraging strategies. The combination of phenotypic diversity and varied environmental conditions makes the cichlid system ideal for the examination of the relationship between ecology and the evolution of visual sensitivity. In this dissertation, I explore several aspects of this relationship. In Chapter 1, I compare the opsin gene sequences from 17 African cichlid species that have evolved in either clear or turbid …

Physiological Bases Of Parental Care In The Burying Beetles, Nicrophorus Orbicollis, Stefania Carmen Panaitof

Doctoral Dissertations

Burying beetles, Nicrophorus orbicollis, have extended biparental care. They bury and prepare small vertebrate carcasses as food for their young. While females provide the most care, single males show a remarkable behavioral compensation after a mate loss. Here, I integrate behavioral and physiological analyses of parental behavior in burying beetles by exploring how hormonal and social factors may interact to mediate brood care.

In Chapter I, I establish Juvenile Hormone (JH) profiles during a breeding bout and show that after larvae hatch, JH titers of single males and paired females are similar. JH titers of single males also respond to …

Patterns And Process During The Diversification Of The Cichlid Fishes In Lake Malawi, Africa, Michael R. Kidd

Doctoral Dissertations

The 500-1000 cichlid species endemic to Lake Malawi constitute one of the most rapid and extensive radiations of vertebrates ever discovered. The objective of this dissertation was to test the assumptions and predictions of several recently published models of cichlid speciation. First, a novel assay of female choice was used to evaluate the role of visual cues during conspecific recognition. The results of this experiment demonstrate that females are able to identify conspecific mates using only visual cues. Second, the assumptions of a recent model of speciation via intrasexual selection were tested by comparing aggressive behavior during territorial contests among …

The Effects Of Temperature On The Physiology And Locomotory Behavior Of The American Lobster, Homarus Americanus, Suzanne M. Cooke

Doctoral Dissertations

Temperature has a pervasive influence on the physiology and behavior of all lobsters, and especially those found in habitats where temperature fluctuates the most. One population of lobsters undergoes a seasonal migration in the Great Bay estuary system in NH, entering the estuary in late spring and returning to the coast in the late summer and fall. This migration may be triggered by physiological or behavioral responses to seasonal temperature shifts.

The first set of experiments examined the effect of temperature on heart rate in order to further understand the influence of temperature on lobster metabolism. Heart rate was measured …

Development Of Muscle Structure And Function In Loliginid Squids, Gabriela Maria Martinez

Doctoral Dissertations

Squid embryos are able to contract their mantle early during the embryonic period.

This dissertation examines the onset of contractile capabilities and subsequent maturation of the main locornotor structures in embryos of two species of loligind squids with a focus on the mantle musculature. The functional implications of the differentiation and organization of the musculature is investigated.

The results of these series of studies indicate that the development and emergence of functional competence of the mantle musculature in loliginid squids is a dynamic process. Differentiation and organization of the musculature of the main locomotor structures does not occur simultaneously and …

Investigations Into The Digestive System Proteases Of Argiope Aurantia (Araneae: Araneidae), Hemolytic Agents Of Spider Venoms, And The Role Of Both In Necrotic Arachnidism, Matthew Joseph Foradori

Doctoral Dissertations

Necrotic arachnidism, or tissue necrosis following spider bites is a widespread problem. Knowledge of the exact mechanism that produces such lesions is still incomplete. Here I have examined spider digestive fluid proteases and spider venom enzymes (e.g., sphingomyelinase D and phospholipase A2) for their potential to cause necrotic lesions, as both are thought to be primary agents.

The digestive fluid of Argiope aurantia was examined for its ability to cleave a variety of extra-cellular matrix proteins, including collagen, elastin, and fibronectin. Having confirmed that the fluid has collagenases, the digestive fluid was injected into the skin of rabbits to observe …

Age, Growth, And Reproductive Biology, Of The Winter Skate, Leucoraja Ocellata, In The Western Gulf Of Maine, James Antoni Sulikowski

Doctoral Dissertations

This study describes the age, growth and reproductive biology of the winter skate, Leucoraja ocellata, in the Western Gulf of Maine. Age was estimated by enumerating annular bands within the vertebral centra. Precision of the age estimates was evaluated using the Index of Average Percent Error and the annual nature of growth band formation was documented using marginal increment analyses. Growth was assessed with the use of the von Bertalanffy growth equation. Age and size at maturity was estimated by measuring morphological and histological changes in the reproductive tract and circulating steroid hormone concentrations. Maturity ogives for males predict that …

A Test Of The Ideal Free Distribution In Panhandling Humans, Leann Louise Milinder

Doctoral Dissertations

The Ideal Free Distribution (Fretwell and Lucas, 1970), an optimization model from behavioral ecology, predicts that a group of animals will distribute themselves across habitats with unequal resources such that all animals have equal success rates. The six experiments of this dissertation demonstrated that humans conform to the IFD with about the same sensitivity as animals and respond similarly when assumptions of the model are violated. The present study also revealed that cooperation, and its effect on the functional size of the foraging unit, may be an important factor in understanding the distribution of social foragers.

Experiments 1 and 2 …

Influences Of Social And Habitat Features On Selection And Use Of Breeding Habitat And Pup Survival In South American Fur Seals, Monica Anne Stevens

Doctoral Dissertations

Quantitative information is lacking about how fur seals use habitat and how this use influences fitness. Such information is important for understanding the prospects for recovery of declining populations like those of South American fur seals (Arctocephalus australis) in Peru. In this study I examined the influences of habitat features and human disturbance on selection of breeding habitat by female fur seals in Peru; and I examined how mortality of pups was influenced by habitat features, female behavior, and the social environment on the beach.

Arctocephalus australis in Peru have declined gradually over the past decade, and declined dramatically (72%) …

Birth, Death And Taxis: North Atlantic Right Whales In The Twenty-First Century, Scott Douglas Kraus

Doctoral Dissertations

Twenty two years of North Atlantic right whale data were analyzed. Several measures indicate reproduction in North Atlantic right whales is in a decline. Calving intervals have increased from about 3.3 years in the 1980's to over 5 years, and the age of first parturition is estimated to be 11 years. Females may lose calves before they are detected, artificially increasing the apparent age of first parturition and possibly affecting estimates of calving interval. Northern feeding habitat use patterns do not appear to affect reproduction.

Right whale mortality data was analyzed by age, sex, and habitat use patterns. A total …

Genetic Basis Of Adaptive Radiation In East African Cichlids, Richard Craig Albertson

Doctoral Dissertations

East African cichlids are a paramount example of adaptive morphological radiation. The most dramatic difference among species occurs in oral jaw design and correlates with ecological niche partitioning. Convergent evolution of trophic forms between lakes suggests a common mechanism. What combination of intrinsic and extrinsic factors constitute this mechanism still remains to be seen. The goal of this dissertation was to examine the genetic basis of shape differences between two closely related cichlid species that employ alternate modes of feeding. This was achieved through a number of independent experiments. First, I used field data to characterize the way in which …

Evolution Of Gender Associated Mitochondrial Dna In Bivalves, Jason Paul Curole

Doctoral Dissertations

Bivalves of the families Unionidae and Mytilidae possess a unique mode of mitochondrial DNA inheritance dubbed sex-limited mitochondrial DNA (mtDNA) inheritance or doubly-uniparental inheritance (DUI). In contrast to the matrilineally restricted inheritance of mtDNA in other metazoans, these bivalves have both matrilineally and patrilineally inherited mtDNA lineages. Although the matrilineally inherited mtDNA (or F type) is present in the somatic tissues of both sexes and the female gonad, the patrilineally inherited mtDNA (or M type) is limited to the male gonad. In Mytilus several observations have been made concerning the evolution of DUI. Firstly, the fidelity of DUI is not …

Life History Dynamics Of Nudibranch Sibling Species In The Genus Dendronotus In The Gulf Of Maine, Chad Gordon Sisson

Doctoral Dissertations

Two different larval types have been described for the nudibranch Dendronotus frondosus (Ascanius, 1774) in the Gulf of Maine. A taxonomic review of adults with planktrophic larvae and those with lecithotrophic larvae revealed regular differences in radula morphology, and no predictable differences in the reproductive system. These data and previous data on a behavioral reproductive isolation mechanism suggest a new species designation for populations of Dendronotus with lecithotrophic larvae. Laboratory studies were used to compare the larval dispersal potential of the two types of Dendronotus. D. frondosus planktotrophic larvae had a potential planktonic period of approximately 11 weeks at 10°C …

Impacts Of The Introduced Crabs, Carcinus Maenas And Hemigrapsus Sanguineus, In Northern New England, Megan Conlon Tyrrell

Doctoral Dissertations

Two introduced crab species are presently found in northern New England, Carcinus maenas, which has been in this region for over 100 years, and Hemigrapsus sanguineus which was first reported in New Hampshire in 1998. Carcinus maenas is a generalized predator and its introduction has had negative effects on several native mollusc species but the community wide impacts of its introduction have been relatively neglected. Hemigrapsus sanguineus is just beginning to establish populations in this region, and its effects on the resident community are unknown. Both monitoring and experimental approaches were used to retroactively infer the impacts of C. maenas …

Comparative Anatomy And Evolution Of The Gastrotrich Muscular System, Richard Hochberg

Doctoral Dissertations

Gastrotrichs figure prominently in metazoan phylogeny because they share a suite of complex morphological characteristics with several other members of the Bilateria. But their microscopic size, cryptic interstitial habitat, and lack of fossil record have exacerbated the usual barriers to phylogenetic analysis. To arrive at a better understanding of gastrotrich systematics and evolution, cladistic analyses and detailed studies of the muscular system were performed.

A fluorescent F-actin stain was applied to whole mounts of 26 species of Gastrotricha to characterize the musculature. Muscle patterns were mapped, their functions inferred, and the direction of evolution hypothesized for several families. The musculature …