The immunological aspects of the interaction between fish and glochidia were studied using glochidia of the Alabama rainbow mussel (Villosa iris). Tested host species was the rock bass (Ambloplites rupestris) and non-host fishes were common carp (Cyprinus carpio) and goldfish (Carassius auratus). Ouchterlony double-diffusion tests showed that both the host and non-host species expressed a specific humoral response to glochidial antigens after being artificially infested with the parasites. Further microagglutination tests were completed to compare titers of host and non-host fishes which were either uninfested, infested, or reinfested with glochidia. These tests showed that host and non-host species exhibit humoral responses of similar strengths (similar titers) to glochidia. In addition, fishes infested with glochidia had higher titers than uninfested fishes, and reinfested fishes had titers higher than both uninfested and infested fishes. Results indicate that fishes express anamnestic responses to glochidia. Because many host-specific parasites mimic their host’s antigens to avoid full immune attack, I tested for antigen mimicry in glochidia. Goldfish were injected with host (rock bass) and non-host (carp) antigens, in the form of sera, and then re-exposed to glochidial antigens at a later time. This test and other experimental results show no evidence of mimicry of host antigens by glochidia before attachment to host fish. Immunoelectrophoresis (IEP) was used to compare precipitation patterns of host and non-host fishes and to determine whether IEP can be used for identifying suitable hosts for a species of mussel. Although there were subtle differences observed between the precipitation bands of host and non-host fishes using IEP, successful molecular host identification will require more precise electrophoretic methods. The precipitation patterns of glochidial antigens and transformed juvenile antigens (reacted with anti-glochidia fish anti-sera) were compared to determine whether glochidia develop new antigens to avoid a full immune attack during glochidiosis. No precipitation occurred in trials using transformed juvenile antigens; therefore, pre-infestation glochidia and post-infestation juvenile mussels are antigenically different. / Master of Science

There is a great deal of concern about the declining freshwater mussel fauna of North America. Although deteriorating water quality and habitat degradation may account for much of the decline, it has been suggested that the exotic Asian clam, Corbicula fluminea, may be having an effect on native unionids. Negative impacts may result directly from competition or indirectly, because of Corbicula population crashes that release ammonia and reduce dissolved oxygen in the sediment. Laboratory tests were conducted to determine the relative sensitivity of native mussel and Asian clam life stages to unionized ammonia, and mussel glochidia were the most sensitive (24-hr LC50 of 0.11 mg/L NH₃-N). Juvenile and adult mussels were similarly sensitivity, with average 96-hr LC50's of 0.49 and 0.52 mg/L NH₃-N, respectively. Adult C. fluminea were the least sensitive, having an average LC50 of 0.80 mg/L NH₃-N. The EPA standard test organism, Ceriodaphnia dubia, had one of the lowest LC50's (0.07 mg/L NH₃-N) of the five species, and the fathead minnow, Pimephales promelas, had the highest (1.18 mg/L). The differing sensitivities of the various life stages are important when trying to determine the impact of an Asian clam dieoff. If a dieoff occurs at a time of year when the more sensitive life stages, such as glochidia are present, then the impact on mussel recruitment may be greater. Two miniature artificial stream tests were used to determine the effect of clam density on dieoff rate, ammonia production and dissolved oxygen levels. Only clams at the highest density of 10,000/m2 experienced 100% mortality. Unionized ammonia levels exceeded 4.0 mg/L, and dissolved oxygen levels dropped below 1.0 mg/L during the dieoff. The amount of unionized ammonia produced was twofold greater than the concentration that produced an LC50 in adult C. fluminea and ~40 times greater than the LC50 for V. iris glochidia. Factors thought to have contributed to the C. fluminea dieoff were flow rate, low dissolved oxygen levels, temperature and perhaps ammonia. A complete dieoff did not occur until flow was stopped and dissolved oxygen concentrations began to drop. One-hundred percent mortality occurred in 38 days for the first test, and 21 days in the second test. Higher water temperatures in the first test (26° C) compared to the second test (average = 21.7°C) are thought to have resulted in the faster dieoff. / Master of Science

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 20, 2009). Thesis advisor: Dr. Charles Rabeni. Includes bibliographical references.

Thesis (M.Sc.)--Victoria University of Wellington, 2008. / Includes bibliographical references.

Over 100 species of freshwater mussels (Unionidae) are endangered or threatened in the United States, and another dozen species support a declining commercial harvest of shells for the cultured pearl industry in Asia. Because of these Significant declines in abundance, a study was undertaken to develop a diet for rearing juvenile mussels, with the goal of long-term propagation of rare species. Three trials were conducted to test various tri-algal and commercial diets and to determine the influence of silt in survival and growth of the rainbow mussel (Villosa iris) and giant floater (Pyganodon grandis). After 45 days post-metamorphosis, juvenile V. iris fed algae with silt exhibited a two-fold increase in shell length (532 μm), and 63.5% survival. Juvenile P. grandis exhibited similar results at 45 days post-metamorphosis. In comparison, all juvenile mussels fed algae without the presence of silt exhibited no increase in shell length after 45 days post-metamorphosis. However, survival varied between species. Survival after 45 days was 5.0% for V. iris and 43.3% for P. grandis. P. grandis is probably more tolerant of a variety of environmental conditions. Analysis of covariance showed that growth rate over time (120 days) of P. grandis was significantly greater than that of V. iris. Shell lengths of P. grandis juveniles fed algae in the substrates kaolin, sterilized silt, sterilized silt plus Aqua Bacta-Aid, and bacteria-colonized silt were Similar, indicating that bacteria were not essential to juvenile digestion or nutrition. Shell lengths of V. iris juveniles fed algae in kaolin or algae in bacteria-colonized silt also were similar after 60 days. Juvenile mussels appear to be pedal-feeding for approximately 120 ± 30 days, depending on the species; hence, silt probably serves as a physical substratum for pedal-feeding mussels to collect food particles. Subsequent tests indicated that growth was significantly correlated with algae high in oils which contain polyunsaturated fatty acids (PUFA). V. iris juveniles fed a tri-algal diet, consisting of Neoehloris oleoabundans~ Phaeodactylum tricornutum, and Bracteacoccus grandis (NPB), with silt substratum showed the best growth over time. Individuals achieved a mean shell length of 1747 μm and had 30.0% survival after 140 days postmetamorphosis. All other tri-algal diets tested enhanced growth over the commonly used green tri-algal mix of Chlorella, Ankistrodesmus, and Chlamydomonas (CAC), and all algae diets enhanced growth over a silt-only diet. Commercial yeast diets did not support growth. After 272 days post-metamorphosis, V. iris fed CAC in silt achieved a maximum shell length of 4520 μm (17-fold increase in length), with a mean length of 2968 μm and approximately 5% survival. After 195 days postmetamorphosis, P. grandis achieved a maximum shell length of 7846 μm (22- fold increase in length), with a mean of 4877 μm and approximately 12% survival. Results of all feeding trials indicate that algae are a suitable food source for rearing early juvenile freshwater mussels. A tri-a1gal diet high in oils resulted in greater growth than all other diets tested. Resident bacteria in riverine sediments were not essential to growth and survival of juvenile mussels. Silt provided some nutritional value, but primarily served as a physical substratum for pedal-feeding juveniles. / Master of Science

The reproductive cycle, population dynamics, and habitat use of the dwarf wedgemussel (Alasmidonta heterodon) were studied in populations from the Tar River, North Carolina and Aquia Creek, Virginia during 1991 and 1992. This mussel is a long-term brooder, spawning in late summer and becoming gravid in September with glochidia maturing in November. Drift net sampling at sites with this species in both rivers during spring and fall of 1991 and spring of 1992 yielded no A. heterodon glochidia, indicating poor or no reproduction at both sites in 1991. Laboratory infestation experiments testing 15 fish species found three hosts for A. heterodon. The tessellated darter (Etheostoma olmstedi), the Johnny darter (EE. nigrum), and the mottled sculpin (Cottus bairdi) all supported glochidial development to the juvenile phase. Six species of sunfishes, four minnows, one sucker, and one catfish species tested in the laboratory did not serve as hosts. Because of seemingly poor reproductive success in 1991, natural infestations of fishes with glochidia were not documented. Age and growth characteristics were calculated using a thin-sectioning technique on valves collected from the Tar River, Aquia Creek, and the Neversink River, New York. As computed by the von Bertalanffy equation, the dwarf wedgemussel reaches a maximum length of 38.70 mm, 45.26 mm, and 45.84 mm in the Tar River, Aquia Creek, and Neversink River, respectively. There were significant differences among the growth curves of A. heterodon from the Tar River and Aquia Creek, and between those of the Neversink River and Aquia Creek. There was no significant difference between the growth curves of dwarf wedge mussels from the Tar and Neversink rivers. Microhabitat parameters including depth, roughness, velocity, turbulence, distance from shore, distance from obstructions, canopy cover, presence or absence of macrophytes, and substratum size were collected for dwarf wedge mussels at the Tar River and Aquia Creek. Microhabitat use differed between the sites, most significantly described by the following variables: distance from shore; turbulence; and velocity. Laboratory preference studies designed to determine preferred substratum size and water velocity were conducted. Dwarf wedge mussels always preferred the finer substratum offered; little preference was exhibited by the mussels for lotic versus lentic flow regimes in the laboratory. / Master of Science

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 76-83). Also available via the Internet.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2008. / Title from PDF cover (viewed March 12, 2009) Includes bibliographical references (p. 63-73)

During the Late Woodland Period in the American Southeast, the amount of space that any individual group could exploit began to shrink, due to the presence of other groups on the landscape. Resource expansion occurred to augment food supplies, resulting in increased exploitation of mussel beds. Because mussels can be extremely sensitive to the characteristics of the waterways they live in, the specific habitat requirements of these animals can be used to reconstruct the environments they were recovered from. In this thesis I use freshwater mussel assemblages to reconstruct hypothetical aquatic catchments and map them onto modern rivers in the Yazoo River Basin and the Tombigbee River Basin. These are used to test ethnographic models of exploited space. I also use detrended correspondence analysis to test if sites exist in mathematical space like they do in physical space along the Yazoo River basin, as observed in the Tombigbee River basin.

As ecologically sensitive organisms, freshwater mussels serve as environmental indicators in the rivers and lakes they inhabit. The South Fork of the Holston River has been impounded and channelized, which can result in habitat loss of riffle and shoal areas and negatively impact native species. The aim of this study is to analyze river conditions on a roughly 40 mile stretch of the S. Fork Holston River, encompassing the distance from Eastman Chemical Company in Kingsport to Boone Lake. Information has been gathered using mussel assemblages from two archaeological sites, 40SL34 and 40SL330, and two historic collecting events, SFHSkm25.1 and SFHSkm27.0. The computer program UNIO analyzes the ecological preferences of all input taxa to compile a list of river conditions, including flow velocity and substrate. Compiling the assemblages from all four sites has revealed an increase in unfavorable conditions for many species, leading to a loss in mussel diversity. What were once the most abundant species in the archaeological sites, Ptychobranchus subtentus and Fusconaia subrotanda, both prefer to live in riffle areas with fast current. Currently, P. subtentus is listed as endangered while F. subrotanda is listed as a special concern species. The most abundant species for both historic collecting events is Lampsilis fasciola, a species that is tolerant of conditions that are unfavorable for many species. The substrate of the S. Fork Holston River, a sandy-gravel, has remained the same, but evidence suggests that impoundment has resulted in the loss of fast-moving currents and riffle areas.