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- Aquatic invertebrates (1)
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Articles 1 - 7 of 7
Full-Text Articles in Aquaculture and Fisheries
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 …
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 …
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.