Browsing by Subject "Aquaculture"

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    Completion Report for Minnesota Technology, Inc. (June 30, 1999): Development of Salmon and Trout Aquaculture in Mine Pit Lakes (1989-1991); Commercial Aquaculture Implications for Water Quality (1991-1993); Constructed Wetlands for Treating Aquaculture Wastes (1993-1996)
    (University of Minnesota Duluth, 1999) Axler, Richard P
    The assessment of environmental impacts associated with intensive salmonid aquaculture, development of tools for predicting impacts, and the development of techniques for mitigating the effects of these potential negative impacts on water resources were the focus of three MTI grants in the period 1989-1996. They are: (1) Development of Salmon & Trout Aquaculture in Mine Pit Lakes, (1989-1991); (2) Commercial Aquaculture Implications for Water Quality, (1991-1993); and (3) Constructed Wetlands for Treating Aquaculture Wastes, (1993-1996) All of these grants were "matched" with grant funds obtained from the Iron Range Resources & Rehabilitation Board, the Minnesota Sea Grant Program (National Oceanic and Atmospheric Administration) and the Minnesota Department of Agriculture. The development of constructed wetlands(#3) subsequently led to the development of an ongoing research, development and demonstration program focused on broader on-site wastewater disposal systems for rural, residential and business needs.
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    Current scientific understanding of the environmental biosafety of transgenic fish and shellfish
    (Revue Scientifique Et Technique - Office International Des Epizooties, 2005) Kapuscinski, Anne
    A fluorescent zebrafish was the first genetically engineered animal to be marketed, and biotechnologists are developing many transgenic fish and shellfish. Biosafety science is not sufficiently advanced to be able to draw scientifically reliable and broadly trusted conclusions about the environmental effects of these animals. The science is best developed for identifying hazards posed by environmental spread of a transgenic fish or shellfish and least developed for assessing potential ecological harms of spread. Environmental spread of certain transgenic fish or shellfish could be an indirect route of entry into the human food supply. The management of predicted environmental risks is in its infancy and has thus far focused on the first step of the risk management process, i.e. risk reduction, via a few confinement methods. There is a critical need to improve scientific methods of environmental safety assessment and management and to gather empirical data needed to substantiate biosafety conclusions and to effectively manage transgenic fish and shellfish. Scientists and potentially affected parties should participate in prioritising the knowledge gaps to be addressed.
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    Demonstration of the FIS-C Aqucultural Bioenergetics Model for Estimating Waste Loads and Optimizing Feeding at Two Commercial Rainbow Trout Farms
    (University of Minnesota Duluth, 1995) Axler, Richard P; Schuldt, J; Tikkanen, Craig A; McDonald, Michael E; Henneck, Jerald
    Fish culture has great potential in Minnesota but the potential for water quality impacts has slowed its development. Since 1989 we have been developing an aquacultural effluent model (FIS-C) for assessing the actual and potential impacts of Chinook salmon waste loads. FIS-C is a based on a bioenergetics model where growth = (consumption - waste losses - respiration losses), where waste losses are egestion and excretion, and metabolic costs are incorporated into respiration losses. The model provides a novel way of estimating the magnitude and seasonality of discharges, because it can discriminate among waste fractions, and also has excellent potential for predicting the effects of different waste collection strategies. The model has already proven to be a robust estimator of consumption, when fish growth is known, for a variety of wild species and for net-pen cultured Chinook salmon. Maximum utility for Minnesota's industry requires expanding its library of physiological parameters to other species and culture systems, and then verifying its predictions in the field. Although FIS-C would be applicable to recirculating systems, land-based flow-through facilities, with short detention times and minimal "in-water" transformations such as solubilization, sedimentation, mineralization and nitrification, provide the best opportunity to accurately verify its predictions. The present study developed the model for rainbow trout, an economically important species in Minnesota, assessed its accuracy for two different successful, commercial trout farms, and initiated the development of an extension bulletin for disseminating our results to the industry.
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    Development of Alternative Onsite Treatment Systems [On-site treatment systems for domestic wastewater: A field comparison of alternative technologies] (1995-1997)
    (University of Minnesota Duluth, 1999) Axler, Richard P
    Approximately 500,000 Minnesota residences depend on individual or small community on-site wastewater treatment systems and 55-70% of them are either not in compliance with State Rules or are failing hydraulically to the surface. This is a direct human health threat from diseases, causes groundwater, stream and lake water quality degradation, and is a major impediment to the environmental and economic sustainability of the State’s water resources. The MTI projects over the period 1995-1999 keyed the development of an extremely successful state-wide partnership between the University (NRRI, UMD and UM-St. Paul), government resource & regulatory agencies (county, region, state and federal), and the private sector (engineering and consulting firms, contractors, vendors) to establish year-round, long-term performance, design criteria, cost-effectiveness and sustainability of alternative technologies for removing pathogens & nutrients from domestic wastewater. The program incorporates existing and newly created technology transfer and outreach/extension programs to efficiently transfer our findings to the private sector, to private citizens, to public planners and to policy makers to expedite potential changes in state or local rules. New business opportunities for new or existing companies have already occurred as a result of this project (>50 industry partners) and the total Match from 1995- 1999 was estimated to be $1,335,280 compared to MTI funding of $189,581 over the same period. Besides the business opportunities related to this project, effective alternative wastewater treatment systems will contribute to resolving some of our rural wastewater problems (e.g. affordable sewage systems for resorts and other commercial establishments throughout rural Minnesota) including the environmentally and politically sensitive northshore of Lake Superior, in addition to numerous other smaller, but sensitive lakes, and in geologically sensitive areas.
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    Development of Thermally-Enhanced Walleye Aquaculture
    (University of Minnesota Duluth, 1988-07-01) McDonald, Michael E
    The culture of walleye in Minnesota can be enhanced by the use of heated waters. Wild-caught walleye fingerlings were maintained in the Aquaculture Research Facility at Minnesota Power's Clay-Boswell Plant. These fingerlings were subsequently induced to feed on a pelleted dry feed and to grow, increasing their size 8.8 times. Fingerling mortality within the facility after conversion to dry diet was minimal. Feed conversion (food fed to body weight increase) ranged from 2.2 to 3.2 over the project's duration. Growth predictions from walleye bioenergetics models, developed for each of the strains in the Aquaculture Research Facility, were extremely close to actual growth in the facility (within 2%). Because of the short duration of the project, it is too early to assess the walleye model's ability to predict mortality and food conversion efficiency. However, initial inspection suggests that it may predict walleye mortality (after fish have switched to dry diet) quite well, but does not predict food conversion well at this point. The walleye bioenergetics model appears to provide a means of detecting growth differences in different strains of walleye, which could be extremely valuable in choosing faster growing strains for future culture.
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    Effects of Aquaculture on Mine Pit Lakes near Chisolm, MN: Restoration of Twin City-South pit lake by fallowing and status of Fraser pit lake
    (University of Minnesota Duluth, 1995) Axler, Richard P; Yokom, Shane; Tikkanen, Craig A; Henneck, Jerald; McDonald, Michael E
    Net-pen salmonid aquaculture was carried out from 1988 to 1993 in the Twin City-South mine pit lake on the Mesabi Iron Range in northeastern Minnesota. A water quality controversy enveloped the aquaculture operation from its inception in 1988. In 1992 the Minnesota Pollution Control Agency mandated that all intensive aquaculture operations in the Twin City - South mine pit lake be terminated by July 1993 and that restoration to baseline (i.e. preaquaculture) conditions be demonstrated within three years. This "fallowing" has led to a rapid recovery to near baseline water quality conditions and an oligomesotrophic, i.e. unproductive, status. Water column improvement in regard to phosphorus and hypolimnetic oxygen concentrations has been particularly rapid. Although baseline conditions were not well defined for TC-S, the P budget for the lake in September and November 1994 was typical of reference pit lakes in the area. Oxygen concentrations in near-bottom water remained above 5 mg02/L in November 1994 even without artificial mixing or aeration during the 1994 growing season. Algal growth was low in 1993, as expected due to artificial mixing, and remained low in 1994 without any artificial mixing. Ammonium has been naturally converted to nitrate which is decreasing faster than expected and at a rate similar to its increase during intensive aquaculture. More rapid reductions in water column phosphorus and nitrogen might have been accomplished during the first summer by allowing the lower hypolimnion to become anoxic in order to promote denitrification and minimize sediment resuspension. The natural burial of sedimented aquaculture wastes due to high ambient rates of erosion of inorganic sediment from the basin walls has effectively minimized sediment nutrient transport to the overlying water column. Fallowing for several years appears to be an effective method for lake restoration of these pit lakes. Our data, and our analysis of the NPDES monitoring data, has shown no change in the water quality of Chisholm's drinking water source, the Fraser pit lake, attributable to aquaculture impacts. This, and no apparent change in the water quality of two nearby pit lakes, Grant and Ironworld in recent years, suggests little or no significant off-site migration of aquaculturally impacted water.
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    Environmental Assessment Tool for Aquaculture in the Great Lakes Basin Version 1.2.
    (2009-09-23) Brister, Deborah; Kapuscinski, Anne
    The Environmental Assessment Tool is a downloadable decision tool specifically designed for the Great Lakes region. It addresses issues relevant to cage and land-based aquaculture in other regions.
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    Insights into the microbiome of aquatic environments: a step towards sustainable fish production
    (2025-02) Jimenez-Lopez, Omar
    Aquatic ecosystems and aquaculture systems are dynamic environments that host diverse microbial communities, playing critical roles in fish health, water quality, and environmental stability. This dissertation explores the microbiomes of fish and their environments across various contexts, providing insights into microbial diversity, structure, and function, with implications for aquaculture management and environmental health.Chapter 1 provides an overview of fish microbiome research, focusing on the salmonid microbiome and aquaculture systems. In Chapter 2, a scoping review and meta-analysis of 16S rRNA-based studies revealed significant variability in the composition of microbiomes associated with gill, skin, and gastrointestinal (GI) samples of salmonid species. Analysis of 3,554 samples from a total of 36 studies, showed that technical factors, such as study methodology and hypervariable region selection, often outweighed biological variables in determining microbiome patterns. Key microbial phyla differed across mucosal sites, underscoring the complexity of microbiome in salmonids. Chapter 3 examines the impact of aquaculture system design on microbial communities by comparing flow-through (FT) and recirculating aquaculture systems (RAS) in U.S. salmonid farming. Using 16S rRNA sequencing, significant differences were observed in microbial diversity and composition between system types. RAS fostered more stable microbiomes and enriched nitrifying bacteria, highlighting its influence on microbial ecology and its potential for sustainable aquaculture practices. Chapter 4 advances this analysis by reconstructing metagenome-assembled genomes (MAGs) from metagenomic data in FT and RAS systems. A total of 282 high-quality MAGs were revealed. Several MAGs identified at the species level were phylogenetically related across sample types in both RAS and FT systems. This research provides a foundation for the description of related genomes and associated metabolic functions in different sample types and facilities.Chapter 5 shifts focus to wild fish and natural environments, examining the gut microbiome and resistome of yellow perch in Minnesota lakes under varying anthropogenic pressures. This study underscores the influence of anthropogenic inputs on antimicrobial resistance genes and opportunistic pathogens found within the gut of wild fish in natural lakes. Collectively, these investigations enhance our understanding of fish-associated microbiomes in both aquaculture and natural ecosystems, providing insights that may inform sustainable aquaculture practices, improve fish health, and control human impacts on aquatic environments.
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    Limnological Assessment of Mine Pit Lakes for Aquaculture Use
    (University of Minnesota Duluth, 1992) Axler, Richard P; Larsen, Christen; Tikkanen, Craig A; McDonald, Michael E; Host, George E
    This study addresses water quality issues associated with current and future uses of mine pit lakes for intensive aquaculture. In current net pen aquaculture operations (Minnesota Aquafarms, Inc.), metabolic wastes and uneaten food are dispersed into the lakewater. Intensive aquaculture at Twin City-South and Sherman increased levels of phosphorus (P) and nitrogen (N) and reduced dissolved oxygen (DO) in the water column, and increased the deposition of organic matter to the bottom relative to their previous conditions and to unused mine pit lakes. Numerous trophic status indices suggest that TC-S and Sherman have shifted (or are shifting) from an oligotrophic state to a more eutrophic one. However, due to MAPs intensive aeration, and circulation, conditions necessary for algal blooms (typical of eutrophication) have been infrequent, due to light limitation from vertical mixing. Blooms of scum-forming bluegreen algae have never been observed.
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    Limnological Re-Sampling of Chisolm Area Mine Pit Lakes with Reference to Former Aquaculture Impacts
    (University of Minnesota Duluth, 2000) Axler, Richard P; Henneck, Jerald
    Limnological surveys were conducted on two mine pit lakes (Twin City-South and Sherman) used for intensive netpen salmonid aquaculture over the period 1988-1995 and an adjacent pit lake (Fraser) used for drinking water by Chisholm, Minnesota. A water quality controversy had enveloped the aquaculture operation from its inception in 1988 to its bankruptcy in 1995. All intensive aquaculture operations in the Twin City-South pitlake were terminated in mid-1993 as mandated by the Minnesota Pollution Control Agency (MPCA) in order to determine if water quality could be returned to baseline values within three years (a condition of continued operation in the Sherman pit lake). The MPCA mandated that restoration to baseline (i.e. pre-aquaculture) conditions be demonstrated within three years. This "fallowing" led to a rapid recovery to near baseline water quality conditions and an oligomesotrophic, i.e. unproductive, status. Algal growth was low in 1993, due to light - limitation from artificial mixing, but remained low in 1994 without any management due to renewed P-limitation. Water column improvement in regard to phosphorus and hypolimnetic oxygen concentrations was particularly rapid. Although baseline conditions were not well defined for TC-S, the P budget for the lake after 18 months was typical of reference pit lakes in the area and oxygen concentrations in near-bottom water remained above 5 mg02/L without artificial mixing or aeration during the next growing season. Waste product ammonium was naturally nitrified to nitrate which decreased at a rate faster than expected, and similar to its increase during intensive aquaculture. More rapid reductions in water column phosphorus and nitrogen might have been accomplished during the first, summer by allowing the lower hypolimnion to become anoxic in order to promote denitrification and minimize sediment resuspension. Unfortunately these were precluded by the regulatory standards. The natural burial of sedimented aquaculture wastes due to high ambient rates of erosion of inorganic sediment from the basin walls effectively minimized sediment nutrient transport to the overlying water column and sediment oxygen demand.