Koi Herpesvirus (KHV), a species-specific DNA virus of the family Herpesviridae, is responsible for mass mortalities of common carp (Cyprinus carpio carpio L.) throughout the world. KHV’s broad geographical distribution and relatively high mortality rate among infected fish, creates significant disposal issues when die-offs occur, especially taking into account the body burden of contaminants in the fish. In locales where adequate disposal facilities are unavailable, or are unable to accommodate additional loadings of contaminated fish carcasses, concerns regarding human and environmental health are raised. During the summer of 2008, residents of the Lake Simcoe Region of southern Ontario, Canada, were faced with a massive die-off of carp, infected with KHV. Carp within the Great Lakes and much of the world are known to bioaccumulate (and biomagnify) contaminants, such as, polychlorinated biphenyls (PCBs), pesticides (e.g., dichlorodiphenyltrichloroethane, DDT, and toxic metals (e.g., mercury). These contaminants have been associated with numerous adverse effects on both human and environmental health, and are thus of important considerations when planning for large-scale carcass disposal, following fish die-offs. Although suites of microbiological tests and water quality assessments are frequently conducted to identify causative factors during extensive fish-kills - assessments of relative contaminant burdens in the carcasses, which should dictate the most appropriate method of carcass disposal - are rarely performed. A case study on Snake Island, Lake Simcoe, Ontario was conducted to further examine the implications of this policy. Soil samples from two known disposal sites and three presumed control locations were sampled on Snake Island and sent to the Analytical Services Unit of Queen’s University for chemical analysis. Although none of the soil samples exceeded any legal guidelines in the present study, there is still concern as future die-offs of other fish species or piscivorous birds and the disposal of large numbers of carcasses may be an issue.

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 66-71).

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 76-108).

Thesis (M.S.)--University of Wyoming, 2009. / Title from PDF title page (viewed on June 14, 2010). Includes bibliographical references (p. 93-104).

The introduction and spread of two Asian Carp species, Bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix have caused severe ecological damage throughout North America. Currently, academic institutions, and state and federal agencies are investigating ways of controlling the spread of these species and managing existing populations to minimize further damage. One promising method of control is the commercial harvest of Asian carps for export to China, as both species are highly valued foodfish throughout Asia. Habitat modification and destruction, along with the questionable quality of fish produced in aquaculture facilities throughout China, have caused members of the foodfish industry to search elsewhere for a high quality product destined for middle and upper class consumers in China. At this time, harvest practices are not standardized, and taking market potential into consideration, it is important to optimize aspects of harvest so commercial fishermen and processors can supply consumers with the highest quality product. Therefore, the present studies evaluated the effects of season (summer and fall), geographic origin (Alton and Peoria Reach), and harvest gear type (trammel nets and hoop nets) on commercially caught fresh fish and those subjected to standard processing practices and simulated shipping conditions to China (blast frozen to core temperatures near - 33oC and stored at- 20oC for 6 wk) using quality evaluation methods common in the foodfish industry. Impacts of season, geographical origin, and gear type on fresh Bighead and silver carp were assessed using fillet internal and external pH, color, Torrymeter freshness, and proximate analysis (percent moisture, protein, lipid, and ash). The effects of season, geographical origin, and gear type on fish processed and held under simulated shipping conditions were analyzed using fillet internal and external pH, color, Torrymeter freshness, K value, and peroxide and aldehyde concentrations. Results indicate negligible effects of season of harvest or geographical origin on final quality of Asian carp products, but the optimization of Asian carp products may require only exporting Bighead carp. Hoop nets yielded better quality fish overall, indicating that commercial fishermen should consider using these specifically for the harvest of fish destined for human consumption. Information assembled in this research can be used by commercial fishermen and processors to develop standardized methods for the harvest of Asian carps. Providing a high quality product is vital considering market potential and the resulting economic stimulation provided to fiscally starved areas where these facilities are located. Most importantly, the development of this industry could, in conjunction with continued academic and agency efforts, offer an independent solution to the serious ecological threat posed by these species.

Invasive bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix), hereafter, bigheaded carp, pose a major threat to the Great Lakes ecosystem as they advance toward Lake Michigan via the Illinois River. However, a series of navigation dams may deter their upstream movement. Starved Rock Lock and Dam (SRLD) is the most downstream gated dam on the Illinois River, therefore presenting the first navigation challenge for upstream migrating bigheaded carp. Before 2015, five acoustic receivers near SRLD detected successful upstream passage of only two of 900 tagged bigheaded carp. I further investigated the permeability of SRLD to bigheaded carp migration as a function of temperature, gage height, and dam operation. In 2015, I added 12 receivers around SRLD and acoustically tagged an additional 118 bigheaded carp downstream of SRLD. I also investigated the timing of bigheaded carp arriving downstream of SRLD using a generalized linear model. The explanatory variables influencing bigheaded carp arrival were average water temperature, average tailwater elevation, and the change in average water temperature. During 2015-2016, acoustic receivers recorded a total of 11 upstream passage events through SRLD, with nine through the dam gates, one through the lock chamber, and one undetermined. Passage through the dam gates occurred most frequently at high water levels when the dam gates were completely out of the water. The probability of upstream migrating bigheaded carp approaching SRLD was positively correlated with rising temperature and high gage. No upstream migrants approached SRLD between mid-September and late March. Overall, dam gates were more susceptible to upstream passage than the lock chamber, and environmental factors accurately predicted the arrival of bigheaded carp at SRLD. Modifying gate use during times of bigheaded carp arrival will likely prevent upstream passage through SRLD and other lock and dam structures.

The apple snail Pomacea canaliculata Lamarck is a native of South America but has invaded Hong Kong since early 1980s. Its feeding has resulted in a tremendous loss in semi-aquatic agriculture, especially rice (Oryza sativa L.) and other aquatic crops such as taro (Colocasia esculenta L.) and water spinach (Ipomoea aquatica Forssk). While spreading to freshwater wetlands, its feeding threatens macrophyte diversity. Owing to its voracious appetite, this invasive snail has also become a competitor of lowland indigenous mollusks. On ecosystem level, over-grazing by high density of apple snails could also induce excessive release of nutrients from macrophytes to water bodies, thus promoting phytoplankton growth and primary production. Measures to control invasive apple snails fall into three categories: mechanical / cultural, chemical, and biological. Among them, biological control methods are appealing because they are usually considered relatively less labor-intensive and more cost-effective. However, both the control efficacy and potential non-target effects should be carefully evaluated before adopting a species in biological control. Although various fish species have been proposed as biological control agents for apple snails, their effectiveness and non-target effects on wetland flora and fauna are largely unknown. This study investigated the feasibility of black carp (Mylopharyngodon piceus Richardson) as bio-control agent for apple snails in both laboratory and field experiments. The laboratory experiment compared the feeding of black carp, common carp (Cyprinus carpio L.) and white-spotted catfish (Clarias fuscus Lacepède) on apple snails. These three species are indigenous and widely aquacultured in southern China. The three species of fish of comparable body length were each offered apple snails of various sizes ad libitum in aquaria. Black carp (fork length: 165 mm; maximum gap width: 16 mm) was the most effective predator, with a predatory rate of 70.5 apple snails in 48 hours. Common carp and white-spotted catfish of similar fork lengths consumed only 58.6 and 15.7 apple snails on average within the same experimental period. Apple snails preyed upon by black carp and common carp were juveniles, with their respective shell length ranged from 3 - 16mm and 3 - 17mm, while that for white-spotted catfish ranged from 3 - 21mm. An 8-week mesocosm experiment was conducted in a constructed wetland during the dry season of 2011 to determine whether black carp (fork length: 170 -185 mm) is as effective as common carp (fork length: 170 - 195 mm) as a bio-control agent for apple snails, but causes less herbivory to macrophytes and predation to non-Pomacea snails. Both species of carp preyed effectively on P. canaliculata, removing almost all apple snail individuals (~ 200 per enclosure) that were small enough to fit into their mouths. The effects of the two fish species on macrophytes were different. Black carp reduced herbivory on macrophytes through reducing apple snail density. However, common carp reduced apple snail density but did not result in a lower level of herbivory because it also grazed on macrophytes. Non-target mollusk density was reduced by both fish species. A one-year whole-pond experiment was also conducted in June 2012 to June 2013 to investigate the applicability of black carp as a biological control agent of apple snails in constructed freshwater wetlands. Three separate constructed freshwater wetlands were used as replicates of the experiment. Each wetland was divided into a control side without black carp and a treatment side with black carp. Four individuals of black carp (fork length 260 - 310 mm) were released to the side of wetland assigned as treatment. Prior to starting the experiment and every three months, density of apple snails and other macro-invertebrates, apple snail egg clutch size and abundance, water quality parameters (total nitrogen, ammonia nitrogen, total phosphorus and reactive phosphorus) were recorded. Black carp was highly tolerant to the low dissolved oxygen in the shallow stagnant waters. It was an effective predator of juvenile apple snails (<5 – 25mm), but it did not result in significant reduction of adult apple snails (shell length >25mm) nor affected their reproduction. In addition, black carp preyed on non-apple snail macro-invertebrates, especially mollusks. In conclusion, our study has shown that juvenile black carp (minimum total length: 300mm) is a suitable bio-control agent of apple snails in shallow water wetlands as it is tolerant of stagnant poor water quality and is an effective predator of apple snails. A major decline of 89.2% in average overall density of apple snail has been recorded in the treatment plots of the three experimental sites after one year. Juvenile snails would be eradicated before they get to mature minimum size (male SL: 25.2 ± 3.3mm; female: 29.8 ± 3.6mm) for reproduction. Given the longevity of black carp, a low stocking density (80-89 individuals ha-1) is sufficient to control apple snail populations. However, black carp reduces the abundance and diversity of non-target macro-invertebrates. Therefore the benefits of the biological control must be weighed against the potential undesirable effects on wetland diversity before adopting in the pest management. To maximize the control efficacy, mechanical methods to eradicate adult snails, for instance hand-picking in the shallow water, should be implemented with biological control effort in an integrated apple snail management program.

Aquatic invasive species are a widespread issue throughout the central United States. Black Carp (Mylopharyngodon piceus) are an aquatic invasive species and are an issue due to their unknown ecological and biological impacts that they may cause to the environment that they invade. Determining movements of an aquatic invasive species such as dam passage or inter-river movement may aid in agency efforts to reduce the spread of an invasive or implement strategies to mitigate its potential expanding range. In this study, I used otolith microchemistry paired with water samples to infer movement and dam passage of Black Carp between eight study regions within the Mississippi River basin. A total of 127 Black Carp otoliths were used and 112 (88%) were classified as immigrants, 14 were classified as potential residents, and one otolith was vateritic so no inferences about movement could be made for that fish. Of the 112 fish classified as potential immigrants, 102 (91%) showed signs of upstream dam passage, and the average instance a Black Carp was inferred to move between rivers was 7 times during their lifetime (SD ± 6.23). These results show that Black Carp may exhibit frequent occurrences of inter-river movement throughout their lives and have high instances of dam passage associated with their movement. This paper presents the first confirming evidence of lock and dam passage by Black Carp, although the apparently expanding range of the species in recent years based on reported captures suggested that lock and dam passage had likely occurred. Evidence of frequent upstream movement and lock and dam passage suggests that future studies should evaluate the efficacy of potential deterrents at locks and dams for preventing or reducing upstream passage by Black Carp.

Black carp consume large quantities of mollusks but food consumption and growth rates have not been studied. Consumption and growth of two sizes of fish fed formulated and natural diets at 20, 25, and 30 C under laboratory conditions were measured. Consumption and growth of fish fed formulated feed increased as temperature increased but followed a convex relationship for fish fed a natural diet. Metabolic and fecal production rates were determined for fish at each temperature. This information was used to develop balanced energy budgets for black carp. Bioenergetic simulation models were constructed to predict consumption and growth in natural systems. Fish inhabiting the Tennessee River and Lake Erie grow faster than fish in other select natural systems of the eastern United States and probably provide a highly satisfactory thermal regime.

Ceftiofur sodium, a third generation cephalosporin, was studied to determine the potential of this drug as an alternative bacterial therapeutic agent for the aquaculture and ornamental fish industry. Grass carp, Ctenopharyngodon idella have been selected as the fish model for this study since they are a good representative for both foodfish and ornamental fish and are one of the major species grown worldwide. Pharmacokinetics of ceftiofur sodium after various routes of administration, histopathologic observations to detect possible toxic effects on the tissues involved in its metabolism and excretion, and the effects on the non-specific immune response were investigated in grass carp. For the pharmacokinetic studies, ceftiofur sodium was administered a single time to grass carp by four different routes : intracardiac (IC), intraperitoneal (IP), intramuscular (IM) and oral (PO) at a dosage of 8 mg/kg body weight. Serial blood samples were obtained and plasma samples were analyzed by high performance liquid chromatography for ceftiofur (as measured its metabolite, desfuroylceftiofur (DFC) and DFC-related metabolite concentrations). Disposition pharmacokinetic data were best described by a two compartment open model for IC and by a non-compartment model with no lag time for IP and IM administrations. Oral absorption of ceftiofur was not observed in this species. Following IC, IP and IM ceftiofur sodium administration, the final elimination half-lives, maximum plasma concentration, time to reach maximum concentration, volume of distribution and plasma clearance were 0.38, 0.45 and 13.86 hours ; 157.09, 31.54 and 8.86 mg/ml ; 0, 0.25 and 0.5 hours ; 0.09, 0.17, 0.53 l/kg ; and 0.21, 0.26, 0.26 ml/min.kg, respectively. Desfuroylceftiofur metabolite was highly bound with plasma protein at pH 7.0 and 8.0. For the histopathological studies, a single intramuscular dose of ceftiofur sodium at three different concentrations, 8 (1X), 40 (5X) and 80 (10X) mg/kg was administered to separate groups of grass carp for evaluation of the potential toxicity to major tissues involved in metabolism and excretion of this drug. These included the anterior kidney, posterior kidney, liver, and spleen. After 48 hours, lesions were seen in the posterior kidney at the highest dose of ceftiofur (10X). Morphological alterations observed microscopically included increased number of renal tubules, tubular necrosis and infiltration of inflammatory cells. No adverse effects on the glomeruli were observed at any concentration of the drug. For the immunotoxicity studies on the non-specific immune response, dosages of either 8 or 40 mg/kg body weight were administered intramuscularly. After 24 and 48 h, leukocyte number, phagocytic ability and H2O2 production were examined in the cells of the pronephros. The results showed that neither dosage had an effect on the number of leukocytes in the pronephros. Phagocytosis was also not significantly altered at either dosage in macrophages from the pronephros. Hydrogen peroxide production was not altered in the pronephros of fish dosed at 8 mg/kg, while at a dosage of 40 mg/kg, H2O2 production was significantly increased. In summary, ceftiofur sodium has potential as an efficacious chemotherapeutic agent for controlling bacterial infection in brood stock and ornamental fish at the recommended dose of 8 mg/kg. A dose as high as 40 mg/kg can be use with careful consideration. This dosage may not directly injure the posterior kidney but it may affect the non-specific immune response of the fish. / Ph. D.