Browsing by Author "McDonald, Michael E"

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    Attraction and Consumption of Crayfish by Centrachids
    (University of Minnesota Duluth, 1996-07) Breneman, Dan; Richards, Carl; Gunderson, Jeffrey; McDonald, Michael E
    Fish attractants are a small but stable component of the U.S. recreational fishing industry, generating $28.1 billion in 1985. Subsequently, fish attractant manufacturers compete for a share of the market, introducing new products annually. Although dilute concentrations of scent have been shown to influence fish behavior, there is little published information regarding the effectiveness of today's marketable products. As a demand for commercial attractants utilizing crayfish scent increases, the need to document crayfish attracting capabilities through fish behavioral research becomes more pertinent. To date, there are few fish attractant products on the market that utilize softshell crayfish, creating an identifiable marketing niche for:crayfish products. Commercial products utilizing Minnesota's abundant crayfish population would further develop Minnesota's crayfish industry, and assist local businesses in competing in the fish attractant market. The mechanism of odor detection in fish is well known. It is also well established that many fish species can detect odors with concentrations in the parts per billion or even parts per trillion. Taste and odor detection in fish is difficult to separate because both senses detect molecules dissolved in water. Odor has been described as distant chemoreception, while taste is nearby or contact chemoreception. Taste detection of molecules dissolved in water can be as sensitive or even be more sensitive than the sense of smell. The spectrum and minimum concentration detected by both olfaction and taste varies greatly between species. A variety of fish behaviors are influenced by odor. These behaviors include: 1) homing migrations, 2) feeding, 3) reproduction, 4) fright reactions, and 5) schooling. Feeding behavior is influenced by both olfaction and taste. The odors most frequently identified as eliciting fish behavior responses have been amino acids and bile acids. Several individual amino acids and combinations of amino acids have been found to elicit olfactory-mediated feeding responses in fish. Other compounds and some amino acid-like components have also been shown to elicit feeding responses. It is generally believed that scent which elicits the greatest response will most often contain mixtures of compounds rather than single substances. Studies attempting to correlate feeding behavior response to olfactory stimuli are limited and have not been conducted on primary U.S. recreational fish species. Two methods have been used to evaluate olfactory responses in fish: 1) behavioral studies, and 2) electrophysiological response of anesthetized fish. Electrophysiological studies are similarly limited in scope and are not necessarily suitable predictors of feeding behavior since they only detect physiological stimulation and not instinctive foraging activity. Soft crayfish are more desirable than hard shell crayfish for use as angling bait, presumably because a perception exists that soft crayfish are a more effective in catching fish. Glycine betaine (found in marine invertebrates and elasmobranch fish, but not in teleost fish) increases the attractiveness of amino acids combinations. Based on reports describing the effectiveness of live and dead crayfish as bait to attract marine crustaceans, it is possible that crayfish possess the amino acid combinations that would attract popular recreational species. While many species universally respond positively to certain amino acids, even closely related species can vary significantly in their response. Crayfish are readily consumed by a variety of fish species including smallmouth bass, largemouth bass, walleye, yellow perch, catfish and others. Major physiological changes occur as crayfish grow. The transformation results in individuals shedding a hard exoskeleton. Following the molt, crayfish are soft, have limited coordination, and are completely vulnerable to predators or other crayfish. As a result, they secure secluded locations to molt and allow the new shell to harden. Since crayfish are vulnerable during the time immediately post molt, it is likely that they would be especially attractive to fish. An odor that is unique to this highly vulnerable life stage may be more attractive than odors from a hard shell crayfish.
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    Crayfish and Baitfish Culture in Wild Rice Paddies
    (University of Minnesota Duluth, 1995-09) Richards, Carl; Gunderson, Jeffrey; Tucker, Paul; McDonald, Michael E
    The objectives of the report are to identify the influence of time of capture, crayfish size, sex, and eyestalk ablation on soft shell crayfish production; to examine crayfish harvest in production-sized wild rice paddies under simulated commercial harvesting; to examine the influence of crayfish densities on wild rice depredation; to asses sucker production potential in wild rice paddies; to assess the potential of aeration for influencing the growth and survival of baitfish and crayfish in wild rice paddies; to assess the commercial viability of softshell crayfish production; to transfer results of this research to potential entrepreneurs, fish farmers, and other interested persons,
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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 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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    Economic and Technologic Development for the Crayfish Industry in Minnesota: Final Report
    (University of Minnesota Duluth, 1992) McDonald, Michael E; DeVore, Philip; Richards, Carl; Skurla, James A; Gunderson, Jeffrey; Kutka, Frank; Merrick, Glenn
    The potential to develop a viable crayfish industry in Minnesota currently exists. Crayfish biomass in our inland lakes can greatly exceed that of fishes; existing harvest techniques appear to have very little impact on the year-to-year crayfish population. Thus, Minnesota's crayfish appear to be an abundant and resilient resource. There are markets for soft and hard shell crayfish for food, soft and hard shell crayfish for bait, and peeled tail meat. A Minnesota crayfish product could currently be inserted in any of these markets, but crayfish as a bait appears to be the most attractive market. There is a very high seasonal demand for bait crayfish and the wholesale prices can be in the range of $15 to $25 per lb for soft shells. In addition to bait markets, large hard shell crayfish for food have a strong international export market, but this market requires that sufficient quantities be shipped at the right times. Also, there is local interest in peeled tail meat for retail sale. We examined four widely distributed Orconectes species (O. virilis, O. propinquus, O. rusticus, O. immunis) to assess commercial soft shell production potential. Crayfish were held in production-sized shallow trays with 2 cm of water at constant temperature similar to that used for commercial soft shell production. Molting success was examined as a function of capture date, sex, and stage of maturity. The timing of life cycle events dictates to a large extent the availability and soft shell production potential of wild caught crayfish, particularly in northern latitudes where market-sized crayfish are often nonjuveniles. Adults typically molt two to three times per growing season, associated with reproductive cycles. Molting rate in the laboratory was highest when crayfish were captured just prior to the wild molt. The first molt of the season was much more synchronous than the second molt. Molt timing varied by sex. Premolt Orconectid crayfish did not change color like Procambarus sp. but could be identified by the decalcification of the cheliped merus. The harvest of several species may be required to optimize soft shell production since synchronous molts occur at different times for different species. Our economic assessment of the crayfish food market suggests that it is relatively flat. This is due to: continued high production costs (including the lack of a proven tail meat separator); regional consumption (primarily in the south-central and Pacific states); unsophisticated packaging and marketing; and seasonally available supply. Crayfish are used in much of the Midwest for fishing bait. Since it is illegal to sell live crayfish for bait in Minnesota, markets in other states will have to be targeted. Problems to overcome include reducing mortality of crayfish shipped to out-of-state markets and drops in sales when crayfish are available closer to the markets. We have analyzed the economic feasibility of food and bait soft shell crayfish production facilities using flow-through and recirculating systems for the first two years of operation. Bait crayfish production in a recirculating system appeared to be the most profitable operation and food crayfish production in a flow-through system appeared to be the least profitable operation. The processing of large quantities of crayfish for a commercial tail meat operation in Minnesota requires that an inexpensive, automated system be developed in order to maintain the product's economic viability. We have evaluated the necessary engineering design components for developing a relatively inexpensive automated crayfish processing system, which could be linked to extant tail meat extruders. We feel that such a system is feasible, and could cost less than $15,000 retail.
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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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    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.