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Articles 121 - 138 of 138
Full-Text Articles in Aquaculture and Fisheries
Use Of High Pressure Liquid Chromatography To Detect And Quantify Oxytetracycline Marks In Walleye Otoliths And Dorsal Spines, Michael J. Hawkins
Use Of High Pressure Liquid Chromatography To Detect And Quantify Oxytetracycline Marks In Walleye Otoliths And Dorsal Spines, Michael J. Hawkins
Electronic Theses and Dissertations
Oxytetracycline (OTC) is used to chemically mark calcified structures in walleye Stizostedion vitreum fry and fingerlings. Current visual methods for detection of these marks are subjective, and biologists are unable to quantify the amount of OTC in a sample. The goal of this study was to determine if high pressure liquid chromatography (HPLC) is a feasible and superior alternative for detecting and quantifying OTC in otoliths of fry-marked and spines of fingerlingmarked walleyes. Study objectives were to validate methodology of extraction of OTC from calcified tissue, detect and quantify extracted OTC using HPLC, and determine a cost comparison of current …
The Relationship Between Green Sea Urchin Spawning, Spring Phytoplankton Blooms, And The Winter-Spring Hydrography At Selected Sites In Maine, Lindsay C. N. Seward
The Relationship Between Green Sea Urchin Spawning, Spring Phytoplankton Blooms, And The Winter-Spring Hydrography At Selected Sites In Maine, Lindsay C. N. Seward
Electronic Theses and Dissertations
The relationship between green sea urchin spawning, spring phytoplankton blooms, and hydrography were examined at multiple spatial scales during the winter-spring of 2000 at selected sites along the coast of Maine. To determine factors contributing to the variation observed in the timing of green sea urchin spawning, sea urchins, phytoplankton, and oceanographic variables were sampled biweekly at four sites in central Maine and three sites in eastern Maine. Water column properties and phytoplankton was intensively examined at sites in central Maine, while sites in eastern Maine were less well characterized. Analysis of gonad indices showed that spawning was protracted in …
Genomic Organization Of Infectious Salmon Anemia Virus, Trent Rector
Genomic Organization Of Infectious Salmon Anemia Virus, Trent Rector
Electronic Theses and Dissertations
Infectious salmon anemia virus (ISAV) is an emerging pathogen of farmed Atlantic salmon (Salmo salar). The development of an effective ISA virus vaccine is a high priority for salmon producers in the U.S. and elsewhere. The process of developing a recombinant vaccine requires complete genetic characterization of the virus. Toward this end we have cloned, sequenced and determined the organization of the eight segments of single-stranded RNA from ISA virus isolate CCBB. The virus was grown in cell culture and purified by density gradient ultracentrifugation. Viral RNA was isolated from purified ISAV and used in the construction of two different …
Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy
Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy
Electronic Theses and Dissertations
The Mytilus edulis species complex includes three smooth-shelled blue mussels, M. edulis (Linnaeus 1 75 8), M trossulus (Gould 1 850), and M galloprovincialis (Lamarck 18 19). When any two of theses species occur sympatrically, hybridization and backcrossing of hybrid and parental genotypes is evident. Despite introgression of genes between taxa their genetic integrity is maintained. To test the hypothesis that a temporal variation in species-specific spawning times is the mechanism limiting hybridization and maintaining genetic integrity in a M edulis and M. trossulus hybrid zone in eastern Maine, mussels were sampled on monthly to semi-monthly intervals throughout 2000 from …
An Armington Model Of The U.S. Demand For Scallops, Fuzhi Cheng
An Armington Model Of The U.S. Demand For Scallops, Fuzhi Cheng
Electronic Theses and Dissertations
The supply of scallops in the United States in recent years has remained relatively stable and the supply source has shifted noticeably from domestic production to imports, especially from China and Japan, where aquaculture production of scallops has been successful. During the past decade, the market share of imported scallops has increased drastically. The scallop fishery in the U.S. is now facing potential competitions from imports. Continuing efforts to provide information on the effect of increasing imports on the U.S. scallop market is warranted. In addition, the impacts of supply increases on domestic scallop prices, either through wild stock enhancement …
Chemosensory-Mediated Deposit Feeding In The Spionid Polychaete Dipolydora Quadrilobata., Timothy J. Riordan Jr.
Chemosensory-Mediated Deposit Feeding In The Spionid Polychaete Dipolydora Quadrilobata., Timothy J. Riordan Jr.
Electronic Theses and Dissertations
Deposit feeding organisms live and feed in marine soft-sediment habitats. This sediment makes up a majority of the material ingested by deposit feeders and contains a variety of edible material that may constitute their principal nutrient source. However, the specific components that are assimilated by these organisms, and the strategies they employ to efficiently collect those components, remain unclear. Sensory interactions between an organism and its surrounding environment typically play an important role in helping the organism detect and locate potential food. Accordingly, chemical sensing by deposit feeders is most likely involved in feeding, yet few specifics about this role …
Ecological Implications Of Rockweed, Ascophyllum Nodosum (L.) Le Jolis, Harvesting, Jill C. Fegley
Ecological Implications Of Rockweed, Ascophyllum Nodosum (L.) Le Jolis, Harvesting, Jill C. Fegley
Electronic Theses and Dissertations
Harvesting of natural resources usually entails substantial removal of the target species. Where such species are dominant members of natural communities, their removal can have important consequences for their own regeneration as well as for the species assemblages associated with them. Rockweed is an ecologically and commercially important intertidal alga in the North Atlantic, and is increasingly being harvested in Maine. The effects of harvesting on regrowth are well known but little is known about its effects on the species that use this alga as habitat. This research focused on the ecological implications of A. nodosum harvesting on the associated …
Invertebrate Egg And Plant Seed Banks In Natural, Restored, And Drained Wetlands In The Prairie Pothole Region (Usa) And Potential Effects Of Sedimentation On Recolonization Of Hydrophytes And Aquatic Invertebrates, Robert Andrew Gleason
Electronic Theses and Dissertations
Sediment is the major pollutant of wetlands, lakes, rivers, and estuaries in the United States and it poses unique threats to wetlands of the Prairie Pothole Region (PPR). Sediment may impact the success of wetland restorations because burial of invertebrate and plant propagules may impact hatching and germination success, and hence, may hamper successional changes throughout interannual climate cycles. Sedimentation also reduces the pool depth and volume, further exacerbating the recovery of hydrophyte communities in restored wetlands. I evaluated the potential impacts of sedimentation on prairie wetlands from several perspectives. First, I evaluated the effects of sedimentation on loss of …
The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey
The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey
Electronic Theses and Dissertations
The Topeka shiner Notropis topeka is a small (< 75 mm) minnow that inhabits prairie streams in several north central plains states. Once widespread and abundant throughout its historic range, the Topeka shiner is now found only in isolated populations. Because of an 80% reduction in occurrence throughout their range, the U.S. Fish and Wildlife Service listed the Topeka shiner as endangered in January 1999. At the time, limited information on habitat preferences and dist1ibution existed for this species in South Dakota. The objectives of this study were to measure local habitat features and water quality conditions at the reach scale at Topeka shiner study sites, create a model using these data to determine favorable habitat conditions, and identify fish species commonly associated with Topeka shiners. Fish and habitat data were collected at 61 tributary sites of the James, Vermillion, and Big Sioux rivers from June through September in 1999 and 2000. Sample sites in 1999 were based on historic Topeka shiner records in the South Dakota Natural Heritage Database. Sample sites in 2000 were based on a draft GIS model identifying potential Topeka shiner streams. Fish were collected with seines between block nets and standard procedures were used to measure physical and hydrological features of stream reaches. Cyprinids dominated the fish community for each river basin during both sample years. Insectivores and omnivores were the dominant trophic classes for each river basin for both sample years. Fish community associations for Topeka shiners were based on two stepwise logistic regression models: abundance of individual species at each site and presence or absence of individual species at each site. The abundance model indicated that Topeka shiners were most commonly associated with orangespotted sunfish Lepomis lutrenis and tadpole madtoms Noturns gyrinus. The presence/absence model showed that Topeka shiners were typically associated with red shiners Notropis lutrenis, tadpole madtoms Noturns gyrinus, black bullheads Ameiurus melas, and bigmouth shiners Notropis dorsalis. Habitat preferences were based on three stepwise logistic regression models: physical habitat water quality, and substrate composition at the reach scale. The physical habitat model indicated that Topeka shiners are associated with stream reaches that had low animal use, overhanging vegetation, stream bank vegetation comprised of sedges/rushes, low depositional zones, and run macrohabitat. The water quality model did not indicate any favorable or preferred conditions. The substrate model indicated that Topeka shiners are associated with stream reaches that had fine gravel or cobble substrates. The results of my study will lead to a better understanding of Topeka shiner distribution and habitat, and aid federal and state agencies in making management decisions that provide for protection and preservation of this species.
Distribution And Impact Of The Oyster Parasite Bonamia Ostreae In Maine, And Its Detection Using Dna Probes, Ryan Carnegie
Distribution And Impact Of The Oyster Parasite Bonamia Ostreae In Maine, And Its Detection Using Dna Probes, Ryan Carnegie
Electronic Theses and Dissertations
Health management efforts in Maine related to the flat oyster (Ostrea edulis) parasite Bonamia ostreae are limited by a lack of knowledge of the parasite’s distribution and impact in both wild and cultured populations. This information would be more readily obtainable with improved diagnostic tools. The objectives of this dissertation were to design sensitive and specific DNA probes for detection of B. ostreae; to assess the prevalence and intensity of parasite infections in wild oyster populations in Maine; and to evaluate growth and mortality of cultured oysters in the Damariscotta River, where B. ostreae is enzootic. A polymerase …
Food Habits And Diet Overlap Of Age-1 And Older Walleye And White Bass In Lake Poinsett, South Dakota, Andrew B. Starostka
Food Habits And Diet Overlap Of Age-1 And Older Walleye And White Bass In Lake Poinsett, South Dakota, Andrew B. Starostka
Electronic Theses and Dissertations
White bass Marone chysops and walleye Stizostedion vitreum coexist in several of the large glacial lakes in eastern South Dakota. I collected age-1 and older white bass and walleye in Lake Poinsett, South Dakota during May, July and September, 1998 to determine food habits and diet overlap using percent by weight to describe diets and Schoener's index (Cxy) to determine diet overlap. Macroinvertebrates were common prey items for white bass in all length groups during all sample dates. The primary macroinvertebrates consumed by white bass were corixids, amphipods and dipterans. Fish, as a group, were second in diet importance over …
Seasonal Investigation Of Native Fishes And Their Habitats In Missouri River And Yellowstone River Backwaters, Shannon J. Fisher
Seasonal Investigation Of Native Fishes And Their Habitats In Missouri River And Yellowstone River Backwaters, Shannon J. Fisher
Electronic Theses and Dissertations
Interactions between the Missouri River and its floodplain have been severely degraded due to channelization and impoundment. Ecologists have assumed that backwaters are a critical habitat component for certain life stages of native fishes; however, documented relationships are limited. During this study, I monitored fishes, invertebrates, and habitats to help determine the importance of backwaters to native fishes of various life stages, and to assess the changes that occur in habitat characteristics and invertebrate densities during periods with differential connectivity. Seven assemblages of fishes, identified with catch-per-unit-effort data, had at least some relationship with the backwaters. The assemblages included two …
Population Status And Characteristics Of Macrhybopsis Gelida, Platygobio Gracilis And Rhinichthys Cataractae In The Missouri River Basin, Selena J. Werdon
Population Status And Characteristics Of Macrhybopsis Gelida, Platygobio Gracilis And Rhinichthys Cataractae In The Missouri River Basin, Selena J. Werdon
Electronic Theses and Dissertations
Few sturgeon chub (Macrhybopsis gelida: Cyprinidae) have been collected in the last decade, therefore their status, habitat selection and morphology were investigated at 172 previous collection sites. Data on two ecologically similar species, Platygobio gracilis and Rhinichthys cataractae, were also collected. Macrhvbopsis gelida were collected at 28 sites on the Powder River (n = 158) in Wyoming and Montana, and at one site on the Yellowstone River (n = 1) in Montana. Age-I, Age-II and Age-III M. gelida were collected. Specimens were 37 to 95 mm in total length. Macrhvbopsis gelida were ripe in mid-June, at water temperatures of 18.3-22. …
Adaptation Of Striped Bass To Sea Water Following Direct Transfer From Freshwater: Morphological, Biochemical, And Physiological Parameters, Judy A. King
Electronic Theses and Dissertations
There has been heightened interest in the biology of striped bass (Morone saxatilis) because of increased pollution in their native spawning grounds and because of their extensive use in landlocked sport fisheries. Their euryhalinity makes them an excellent species for osmoregulation studies. The objective of this research was to study the rate of adaptation of striped bass gills to sea water (3% salt) after direct transfer from freshwater using biochemical (ion transport enzyme levels), physiological (chloride efflux), and ultrastructural methods. Striped bass have specialized osmoregulatory cells located on the interlamellar and afferent surfaces of their gill filaments as shown by …
Parasites Of Salmonid Fishes From Southcentral Alaska, James Carl Riis
Parasites Of Salmonid Fishes From Southcentral Alaska, James Carl Riis
Electronic Theses and Dissertations
The importance of fish parasites is directly related to the value of the fish they affect. Alaskan salmonids are extremely important and are constantly increasing in value to the United States. Other countries, such as Japan and Russia, are also finding Alaskan salmonids important as a foodstuff. If human populations continue growing at present rates, in only a few years there could be twice as many people eating fish. As a recreational asset in Alaska, salmonids rank at or near the top, both for sportfishing and as a natural attraction. It is thus important from an economic point of view …
A Study Of Sex Differentiation In Lebistes Reticulatus As Affected By Estradiol Stilbestrol And Pregneninolon., Esther Coogle
A Study Of Sex Differentiation In Lebistes Reticulatus As Affected By Estradiol Stilbestrol And Pregneninolon., Esther Coogle
Electronic Theses and Dissertations
No abstract provided.
A Cytological Study Of The Ciliated Epithelium Of Nucula Castrensis Hinds., Dorothy Blumer
A Cytological Study Of The Ciliated Epithelium Of Nucula Castrensis Hinds., Dorothy Blumer
Electronic Theses and Dissertations
Ever since the latter part of the 17th century, when ciliary movement was first observed, the study of ciliated cells has been of great interest to biologists, particularly to physiologists. In 1713 Leeuwenhoek recorded some observations he made on ciliary activity, using his primitive microscope. A knowledge of the structure and function of ciliated cells is also of importance in that branch of medicine pertaining to disorders of the respiratory passages and the movement of the ovum in the uterine tubes. The bivalve molluscs have come to be the classical example for the study of ciliated cells, both because of …
The Anatomy, Systematic Position, Natural History And Economic Importance Of The Spoonbill Ganoid, Polyodon Spathula., Oscar H. Steinberg
The Anatomy, Systematic Position, Natural History And Economic Importance Of The Spoonbill Ganoid, Polyodon Spathula., Oscar H. Steinberg
Electronic Theses and Dissertations
No abstract provided.