Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 26-28). Also available on the World Wide Web.

No description available.

Graduation date: 1995

The decline of many freshwater mussel populations in the United States has brought about the need for facilities in which mussels can be held for purposes of relocation, research, and propagation. The Aquatic Wildlife Conservation Center (AWCC) of the Virginia Department of Game and Inland Fisheries (VDGIF) serves as a freshwater mussel conservation facility in southwest Virginia. The goals of this study were: (1) to determine whether adult freshwater mussels could maintain energy reserves at AWCC (2) to determine whether adults could produce mature gametes at AWCC and (3) to establish suitable rearing conditions for juvenile mussels at the AWCC. In fall 2002, four species of mussels, Villosa iris, V. vanuxemensis, Amblema plicata, and Pleurobema oviforme, served as surrogates for endangered species and were relocated to the AWCC. Three energy reserves (glycogen, protein, and lipid) were measured seasonally (fall 2002 to summer 2004) from mantle tissue and compared between AWCC specimens and those from their wild source populations. The gametogenic stage of each species was also compared to determine whether gametogenesis was occurring in captivity. In summer 2003, the first of two juvenile experiments tested the effects of three rates of water flow (1 L/min, 3 L/min, and 7 L/min) on the survival and growth of V. iris and Epioblasma capsaeformis reared in flow-through troughs. In summer 2004, round flow-through tanks were used to assess the effects of three sizes of substrate (fine sediment, fine sand, and coarse sand) and sampling frequency on the survival and growth of V. iris. Gut content analyses also were conducted at the end of each experiment to determine which algal species were being consumed. Overall survival rates were as follows: A. plicata, 100 %; V. vanuxemensis, 86 %; V. iris, 79 %; P. oviforme (2002 collection), 53 %; and P. oviforme (2003 collection), 50 %. All energy reserves varied among seasons, but every species except P. oviforme (2003 collection) had levels higher than those in source populations at the end of this experiment. Glycogen appeared to be the best indicator of condition in these species, with protein also being important in the 2003 collection of P. oviforme. Mature gametes were found in all four captive species in 2003 and 2004, with lipids appearing to fuel gametogenesis. Additionally, gametogenesis was occurring earlier in captive long-term brooders than in the wild, possibly due to warmer water temperatures at AWCC. The first juvenile experiment resulted in 15 % overall survival, with 1 L/min having the greatest survival (18 %), and the 3 L/min having the greatest growth (656 μm). In the second experiment, dishes left unsampled had significantly greater survival (40 %) (P<0.05) of juveniles than those which were sampled (27 %). The unsampled fine sand treatment had significantly greater survival than the other two unsampled treatments (52 %) (P<0.001). Sampled juveniles in fine sediment had the greatest growth (887 μm). Also, juveniles from Experiment 1 were consuming primarily Navicula, with Coelastrum and Chlorella consumed in greatest abundance in Experiment 2. Results indicate that most adult mussels maintained energy reserves and produced mature gametes, and that juveniles of V. iris had good survival and growth. Only P. oviforme had survival rates lower than expected and did not appear to maintain condition at AWCC. Based on results of the species tested, environmental conditions at AWCC appear suitable for the survival of most adult and juvenile freshwater mussels. / Master of Science

Storvuxna musslor i sötvatten (stormusslor) kan ha drabbats av en allvarlig tillbakagång i såväl Sverige som hela världen. Tidigare undersökningar i Sverige och andra delar av världen visar på en kraftig tillbakagång och brist på en fungerande föryngring hos arterna flodpärlmussla (Margaritifera margaritifera) och tjockskalig målarmussla (Unio crassus). I tidigare undersökningar i Sverige har fokus främst varit att försöka kartera arternas förekomst och utbredning, men inte dess föryngring. Syftet med denna studie är att undersöka föryngringen av samtliga arter stormusslor i vattensystemen Tidan, Lidan och Mariedalsån i Västra Götalands län. Sju lokaler valdes selektivt ut för att representera några av de bästa i de tre vattensystemen. Inventeringen utfördes främst med vattenkikare men även med luther- räfsa. Sedimentprov utfördes i lokalerna för undersökning av juvenila musslor. Musslorna räknades, artbestämdes, mättes och åldersbestämdes utifrån räknade vinterringar på skalen. Resultatet i studien pekar på att föryngringen är mycket dålig i flertalet lokaler även hos vanligt förekommande arter i landet som allmän dammussla (Anodonta anatina) och spetsig målarmussla (Unio tumidus). Förekomsten av arter stormusslor i lokalerna är dålig och tyder på relativt artfattiga vatten i Tidan, Lidan och Mariedalsån. Då de inventerade lokalerna ska representera några av de bästa i de tre vattensystemen är resultaten på föryngringen i vattendragen mycket oroväckande. Fortsatta studier bör göras på föryngringen i vattendragen för samtliga arter stormusslor i Västra Götalands län, nationellt och internationellt. / Freshwater mussels (Unionoida) may have been substantially reduced in Sweden as well as the whole world. Earlier studies show that the species Margaritifera margaritifera and Unio crassus has been substantially reduced and there are several localities with no reproduction in Sweden and in several other parts of the world. Other species of freshwater mussels in Sweden have not been studied very much and the focus of studies in Sweden has been on the species existence, not their reproduction. The purpose with this study is to examine the existence of reproduction of different kind of freshwater mussels in the water systems Tidan, Lidan and Mariedalsån in Sweden. Seven localities were choosing selective for the study to represent some of the best localities in the water systems. The freshwater mussels were studied on the bottom and in the sediment. The lengths of mussels were measured and the winter rings were counted to estimate the age of the mussels. The result of this study point on a very bad reproduction in several localities even with the most common species in Sweden and the diversity of species are low in the water systems Tidan, Lidan and Mariedalsån. These localities were supposed to represent some of the best localities in the water systems and because of that the result of the bad reproduction is very concerning. More studies of the reproduction of freshwater mussels even the more common species is recommended in Sweden and other countries of the world.

Prevention and removal of biofouling from nets and product is a huge expense in the aquaculture industry. Of the many technologies that slow the accumulation of biofouling, copper-based coatings are used most commonly as they are a relatively inexpensive and effective option. However, they can leach into the marine environment and have potentially harmful impacts on marine life. In previous studies, sea urchins have shown potential as a non-toxic alternative to control fouling. In this field study, five different stocking densities (i.e. 0, 30, 60, 90, 120 urchins net-1 or 0, 2.46, 4.91, 7.37, 9.82 urchins m-2) of green sea urchins, Strongylocentrotus droebachiensis, were randomly placed in 30 mussel predator exclusions nets (with six replicates per density treatment) in order to test the effect of urchin density on biofouling intensity and urchin/mussel growth. Mussel predator exclusion nets were chosen to house the urchins since they are necessary to protect mussels from diving ducks and sea otters on the west coast of Vancouver Island, British Columbia, Canada. The urchins provide a means of controlling biofouling as well an additional marketable crop to offset predator net expenses. After 174 days, the percent net occlusion, mussel growth, and urchin growth were quantified. Nets with urchins were significantly less fouled than those without urchins. Fouling on nets with higher stocking densities of urchins (90 and 120 urchins net-1) was significantly less than that on nets with the lowest stocking density (30 urchins net-1). Fouling was no longer significantly reduced at densities >60 urchins net-1 or 4.91 urchins m-2. While fouling was significantly reduced in the presence of urchins, it was not completely eliminated as they were only able to access the inside surface of the nets. There was no significant difference in mussel growth at the different urchin stocking densities, but urchin somatic growth and gonad growth did decline with increasing urchin stocking density. Mussels and sea urchins can be successfully co-cultured with no food inputs, but there is a trade-off between biofouling control and urchin growth. / Graduate

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 63-77). Also available via the Internet.

<p>Storvuxna musslor i sötvatten (stormusslor) kan ha drabbats av en allvarlig tillbakagång i såväl Sverige som hela världen. Tidigare undersökningar i Sverige och andra delar av världen visar på en kraftig tillbakagång och brist på en fungerande föryngring hos arterna flodpärlmussla (Margaritifera margaritifera) och tjockskalig målarmussla (Unio crassus). I tidigare undersökningar i Sverige har fokus främst varit att försöka kartera arternas förekomst och utbredning, men inte dess föryngring. Syftet med denna studie är att undersöka föryngringen av samtliga arter stormusslor i vattensystemen Tidan, Lidan och Mariedalsån i Västra Götalands län. Sju lokaler valdes selektivt ut för att representera några av de bästa i de tre vattensystemen. Inventeringen utfördes främst med vattenkikare men även med luther- räfsa. Sedimentprov utfördes i lokalerna för undersökning av juvenila musslor. Musslorna räknades, artbestämdes, mättes och åldersbestämdes utifrån räknade vinterringar på skalen. Resultatet i studien pekar på att föryngringen är mycket dålig i flertalet lokaler även hos vanligt förekommande arter i landet som allmän dammussla (Anodonta anatina) och spetsig målarmussla (Unio tumidus). Förekomsten av arter stormusslor i lokalerna är dålig och tyder på relativt artfattiga vatten i Tidan, Lidan och Mariedalsån. Då de inventerade lokalerna ska representera några av de bästa i de tre vattensystemen är resultaten på föryngringen i vattendragen mycket oroväckande. Fortsatta studier bör göras på föryngringen i vattendragen för samtliga arter stormusslor i Västra Götalands län, nationellt och internationellt.</p> / <p>Freshwater mussels (Unionoida) may have been substantially reduced in Sweden as well as the whole world. Earlier studies show that the species Margaritifera margaritifera and Unio crassus has been substantially reduced and there are several localities with no reproduction in Sweden and in several other parts of the world. Other species of freshwater mussels in Sweden have not been studied very much and the focus of studies in Sweden has been on the species existence, not their reproduction. The purpose with this study is to examine the existence of reproduction of different kind of freshwater mussels in the water systems Tidan, Lidan and Mariedalsån in Sweden. Seven localities were choosing selective for the study to represent some of the best localities in the water systems. The freshwater mussels were studied on the bottom and in the sediment. The lengths of mussels were measured and the winter rings were counted to estimate the age of the mussels. The result of this study point on a very bad reproduction in several localities even with the most common species in Sweden and the diversity of species are low in the water systems Tidan, Lidan and Mariedalsån. These localities were supposed to represent some of the best localities in the water systems and because of that the result of the bad reproduction is very concerning. More studies of the reproduction of freshwater mussels even the more common species is recommended in Sweden and other countries of the world.</p>

Studies were carried out on microsomes of the digestive gland of the common mussel, Mytilus edulis L. Cytochrome P-450 specific content, and the specific contents or activities of other mixed-function oxidase (MFO) components, and the oxidative activities benzo[a]pyrene hydroxylase (BPH) and NADPH-independent 7-ethoxycoumarin O-deethylase (ECOD), all varied seasonally. To varying extents, correlations were seen between changes in these parameters, and changes in the mussel reproductive cycle and/or the seasonal variation in water temperature. The existence of P-450 isoenzymes was indicated by asynchrony in the seasonal changes in BPH and NADPH-independent ECOD activities relative to the changes in P-450 specific content, and by seasonal changes in cytochrome P-450 A max and the microsomal protein profile on SDS PAGE. Indications of P-450 isoenzymes were also obtained from purification studies, and from kinetic studies of NADPH-independent ECOD activity (multiphasic kinetics seen with 7-ethoxycoumarin concentration). The purification scheme essentially comprised sodium cholate solubilization, (NH4)2SO4-protein fractionation and affinity and ion-exchange column chromatographic steps. Two cytochrome P-450 peaks were obtained on DEAE-sephacel ion-exchange chromatography (KC1 elution), the overall purification for the major peak being x 20, with a yield of 5%. The final detergent-free P-450 preparation was largely in the low-spin state, and had a monomeric molecular weight of 53.0 Kd. Ligand-binding experiments were performed on partially-purified cytochrome P-450 preparations. Type II spectra were obtained with N-substituted imidazole compounds, metyrapone and pyridine, but with compounds giving type I spectra with mammalian cytochromes P-450 (testosterone, 7-ethoxycoumarin, a-naphthoflavone and SKF 525-A), reverse type I spectra were seen. In vitro MFO metabolic activity toward possible xenobiotic and endogenous substrates, was limited, and surprisingly, largely NADPH-independent. NADPH-independent ECOD activity was susceptable to modulators of mammalian MFO activity, and indicated to be cytochrome P-450-mediated. Mussel microsomal fraction and microsomal-extract were shown to inhibit rat MFO activities and hexobarbital binding to rat cytochrome P-450. These and other results are discussed in terms of a possible "endogenous blocking" of the substrate-binding site of the mussel P-450, and in terms of possible mechanisms of cytochrome P-450 catalytic action in addition to monooxygenation, such as peroxidation. Mussel cytochrome P-450 specific content was relatively unaffected by a variety of mammalian model P-450 inducers, with the exception of a small elevation with exposure to 3-methylcholanthrene (3MC). In contrast, NADPH-cytochrome c (P-450) reductase activity was slightly more responsive. An increase in NADPH-independent ECOD activity with 3MC-exposure was seen at one time of the year, but not at other times.

Thesis (M.E.S.)--Evergreen State College, 2009. / "June, 2009." Title from title screen (viewed 4/8/2010). Includes bibliographical references (leaves 48-54).