Kentucky is one of the largest coal-producing states; surface coal mining has led to changes in natural land cover, soil loss, and water quality. This study explored relationships between actively mined and reclaimed areas, vegetation change, and water quality parameters. The study site evaluated 58 watersheds with Landsat-derived variables (reclamation age and percentage of mining, reclaimed forest, and reclaimed woods) as well as topographic variables (such as elevation, slope, drainage density, and infiltration). Water samples were collected in spring (n = 9), summer (n = 14), and fall (n = 58) 2017 to study changes in water quality variables (SO42−, alkalinity, conductivity, Ca2+, Mg2+, Mn2+, Al3+, and Fe2+, Fe3+) in response to changes in land cover. Pearson correlation analyses indicated that conductivity has strong to very strong relationships with water quality variables related to coal mining (except Al3+, Fe2+, Fe3+, Mn2+, elevation, slope, and drainage density) and land cover variables. In addition, separate regression analyses were performed, with conductivity values based on samples collected in the fall. First, conductivity responses to mining percentage, reclamation age and topographic variables were examined (adjusted R2 = 0.818, p < 0.01). Next, vegetation cover change parameters were added to the same model, which yielded slightly improved R2 (adjusted R2 = 0.826, p < 0.01). Finally, reclamation age and mining percentages were used to explain the quantity of reclaimed forested areas as a percentage of watersheds. The model was significant (p < 0.01), with an adjusted R2 value of 0.641. Results suggest that the quantity (area as a percentage) of reclaimed forests may be a predictor of the mining percentage and reclamation age. This study indicated that conductivity is a predictable water quality indicator that is highly associated with Coal-Mine-Related Stream Chemistry in areas where agriculture and urban development are limited. Water quality is not suitable for various purposes due to the presence of contaminants, especially in mined sites. These findings may help the scientific community and key state and federal agencies improve their understanding of water quality attributes in watersheds affected by coal mining, as well as refine land reclamation practices more effectively while such practices are in action.

Aquaponics is the integration of aquaculture and hydroponics where nutrients released by growing fish are utilized by plants grown in a soilless culture, often in a controlled environment. Potential advantages of aquaponics include improved sustainability, reduced resource consumption, and fewer environmental impacts compared to conventional aquaculture. Based on a 2014 survey, it was found that most respondents were practicing aquaponics as a hobby. Other groups of respondents were educators, non-profit organizations that operate aquaponic systems, commercial operators, and consultants that sell goods, material, and services. Although many proponents cite the opportunity to create a commercially viable food production system few (if any) ventures have demonstrated sustainable financial outcomes. In general, much of the peer-reviewed aquaponic publications and popular literature, and despite the efforts of some investigators, lacks a methodical scientific basis for describing the essential mechanics, relationships, and culture methods within aquaponic systems. Many systems evolved from small-scale experimental facilities devised by trial and error methods and were implemented with locally limited appropriate species, limited finances, and distorted market situations. Many of the published aquaponic experiments are based on small systems, short growth trials, and weak experimental design. The predominant system design approach is based on a relatively small number of experiments. This review introduces notation and algorithms that are intended to standardize the numerous critical values essential in aquaponics for purposes of determining design criteria and operational parameters including flows, the concentration of water quality constituents, metabolite production, and productivity of plant and animal segments in an aquaponic systems. The objective of this systematic approach is to employ scientific methods that provide research results that can be replicated, challenged, and improved. This methodology is expected to facilitate more rapid development of scientific information, productive systems, and rational economic applications. This approach is crucial for commercial applications where production cost, product value, and investment returns are of critical importance for practitioners that envision investment in new ventures. For hobbyists and educators, economic issues may not be as important as the self-sufficiency and natural synergism aspects, personal satisfaction, and the learning experience that result from existing state-of-the-art of aquaponic practices. These outcomes remain for all and a clearer understanding of smaller personal systems is likely to be enhanced.

A synthetic gonadotropin-releasing hormone, cGnRH IIa (D-Arg(6), Pro(9)-NHet), was evaluated versus commercially available hormones as a spawning aid for Largemouth Bass Micropterus salmoides with two trials each season for two seasons. In season one, human chorionic gonadotropin (HCG) was applied at a rate of 4,000 IU/kg for females and 2,000 IU/kg for males. Ovaprim and cGnRH IIa was applied at 0.5 mL/kg and 0.1 mg/kg in a single injection. The respective response rate for HCG, Ovaprim, and cGnRH IIa among females was 88.9, 77.8, and 50%. Mean latent period for HCG, Ovaprim, and cGnRH IIa among females was 33.4, 34.4, and 34.7 h. In season two, four treatments were used: saline, HCG, cGnRH IIa, and cGnRH IIa with the dopamine inhibitor domperidone (cGnRH IIa+D). Males did not express milt in either season, so they were euthanized to collect testes and prepare a fertilization solution. Spawns were segregated by spawning agent and incubated in hatching jars. Response rates of females to saline, HCG, cGnRH IIa, and cGnRH IIa+D were 0, 75, 90, and 75%, respectively. There was no statistically significant difference among the treatments for response, eggs per kg of female body weight, number of eggs/g, or latent period. Hatched larvae yield from hatching jars ranged from 0.5% to 19.5%. The spawning agent cGnRH IIa had similar efficacy as commercially available HCG. This investigation also examined the efficacy of a fertilization solution generated following extraction and maceration of testes. Testes of mean weight 6.6 g yielded spermatozoa at a mean density of 6.0 x 10(9) spermatozoa/mL. There was no significant effect of inducing agent on sperm density of solution. Spermatozoa were characterized in three groups regarding motility: nonmotile, progressively motile (desired), and non-progressively motile. Sperm motility videos revealed a mean progressive motility of 7.9%. Mean values for nonmotile and non-progressively motile spermatozoa were 75.5% and 16.6%, respectively. Mean duration of motility was 116 s.

Small recirculating aquaculture systems (RASs) are used to market live food fish, particularly in certain ethnic markets. We evaluated fish performance, water quality, and physiology of Channel Catfish (CCF) Ictalurus punctatus and Largemouth Bass (LMB) Micropterus salmoides that were harvested from ponds, transported, and held live at two stocking densities in a small RAS. One trial was conducted for each species, with two treatments (20 and 40 kg/m(3)) in each trial. Trials were conducted in individual RASs without feed during a holding period of 8 d. Water quality for each holding tank was measured at stocking and daily thereafter (24, 48, 72, 96, 120, 144, 168, and 192 h). Blood samples were obtained from fish to evaluate physiological response. Both CCF and LMB survived well in the system, with no mortality in either treatment. Average weight loss across both trials at a temperature of 15 degrees C was 3.1% for CCF and 4.8% for LMB. Total ammonia nitrogen (TAN), un-ionized ammonia (UIA), nitrite, and nitrate increased significantly over time in both trials. Mean water pH was significantly lower and mean TAN and UIA were significantly higher in the 40-kg/m(3) treatment for both trials. Blood glucose rose significantly after harvest and returned to a resting state during the holding period in both species. Blood sodium, potassium, and chloride also returned to a resting state within 24-72 h in the holding system. Estimated accumulation of TAN was 35.6 mg kg fish(-1)center dot d(-1) for CCF and 21.6 mg kg fish(-1)center dot d(-1) for LMB. Although the RAS biofilter was unable to convert ammonia to nitrate at the rate it was produced, the holding systems performed adequately at the densities evaluated. These trials provide data in support of the common practice of holding food-size CCF and LMB at densities of 40 kg/m(3) or less over a period of 8 d in a small RAS.

Two species from the families Acipenseridae and Polyodontidae, Russian sturgeon (Acipenser gueldenstaedtii, Brandt and Ratzeberg, 1833; functional tetraploid) and American paddlefish (Polyodon spathula, Walbaum 1792, functional diploid) were hybridized. The hybridization was repeated using eggs from three sturgeon and sperm from four paddlefish individuals. Survival in all hybrid family groups ranged from 62% to 74% 30 days after hatching. This was the first successful hybridization between these two species and between members of the family Acipenseridae and Polyodontidae. Flow cytometry and chromosome analysis revealed two ploidy levels in hybrids. The chromosome numbers of the hybrids ranged between 156–184 and 300–310, in “functional” triploids and “functional” pentaploids, respectively. The hybrid origin and the ploidy levels were also confirmed by microsatellite analyses. In hybrids, the size and the number of dorsal and ventral scutes correlated with the ploidy levels as well as with the calculated ratio of the maternal and paternal chromosome sets. An extra haploid cell lineage was found in three hybrid individuals irrespective of the ploidy level, suggesting polyspermy. Although the growth performance showed high variance in hybrids (mean: 1.2 kg, SD: 0.55), many individuals reached a size of approximately 1 kg by the age of one year under intensive rearing conditions.

Detailed knowledge of the life history of Paddlefish Polyodon spathula is a relatively recent scientific chapter. The foundation was initially established in Missouri, where there was a significant sport fishery for Paddlefish; initial observations on natural spawning and subsequent techniques for artificial propagation were developed there. Building on this impetus, a different trajectory was initiated in the late 1970s by our research group, one focusing on aquaculture with a goal of developing a breeding program to produce all-female progeny; our collaboration continued over the next three and one-half decades. Managed reproduction through artificial propagation, nursing of juveniles and grow-out for commercial production were components of this program, but more detailed techniques such as ploidy manipulation, sperm physiology, and cryopreservation were also developed. Our present objective is to highlight the improvements in artificial propagation that have been incorporated into hatchery programs. Initially, ovulation was induced with pituitary glands, but today Luteinizing Hormone Releasing Hormone analog (LHRHa) is used; ovulated eggs were collected by laboriously stripping, then a caesarian-section technique used in sturgeon was adopted, and subsequently the Minimally Invasive Surgical Technique (MIST) was introduced. Today, a Modified MIST technique offers a more efficient means of collecting eggs. Nursing of juveniles continues to evolve; primary nursing is now commonly done in tanks where fish may be offered live food during training to a prepared diet instead of starting culture in enriched ponds managed for zooplankton. The development of Paddlefish artificial propagation has benefitted from techniques which were initially developed and used in sturgeon culture. These operational hatchery techniques are common to both culture for restoration stocking and food fish production.

Hydroponics and aquaponics have been gaining popularity to grow produce. Escherichia coli O157:H7 may internalize within edible produce. This study was to investigate E. coli O157:H7 internalization in red sails lettuce in a custom designed/constructed model hydroponic system under laboratory-controlled conditions. The objective was to determine not only the likelihood and level of internalization within hydroponically-grown lettuce but also potentially facilitated internalization with injured lettuce roots. The hydroponic tank was contaminated with Escherichia coli O157:H7 (E. coi) at 5-log CFU/mL. Roots of randomly selected plants were damaged by cutting either two- or three-times (two experimental treatment groups). Experimental control did not have root damage. Following lettuce harvest and surface decontamination, E. coli was enumerated on 3-M petrifilm (TM) EC. Internalized E. coli was detected at 2.4 +/- 0.7, 4.0 +/- 1.9, and 3.3 +/- 1.3 log CFU/g in control, lettuce with two-, and three-cuts to their roots, respectively. Root injury showed a trend (p > 0.05) towards increasing E. coli internalization. Two-vs. three-cuts to roots did not (p > 0.05) affect E. coli internalization, although it showed 0.9-log CFU/g of a numerical difference. The highest level of internalized E. coli was detected at 4.7 log CFU/g in a lettuce plant that received two cuts to its root system.

Escherichia coli O 157:H7 can internalize in produce. Therefore, a food safety risk exists for lettuce grown using mixed water sources such as aquaponics, which combines aquaculture with hydroponics. Objectives were to determine antimicrobial efficacy of UV-radiation on reduction of E. coli/coliform in a pilot-scale demonstration aquaponic system and assessment for possibility of E. coli/coliform internalization in aquaponically-grown lettuce. Water from aquaculture and hydroponic was sampled for 6 weeks prior to lettuce harvest. Water and lettuce samples were spread-plated on 3-M petrifilm (TM) EC (E. coii/coliform) and on m-Endo agar. The average bacterial counts in aquaculture raceways were approximately 10(2) CFU/ml and 10(4) CFU/L on 3-M petrifilm and m-Endo agar, respectively. Bacterial counts did not (p > 0.05) increase in the aquaculture raceways or hydroponic greenhouse, suggesting that neither fish nor plants contributed to bacterial growth. The coliform bacteria detected in the aquaponic system reflected their normal presence in the environment where the aquaponic system was located. UV treatment reduced (p < 0.05) bacterial counts by approximately 1.5 and 3.0-log on 3-M petrifilm and m-Endo agar, respectively. Internalized coliforms or E. coil were not detected in lettuce. This study demonstrates the effectiveness of coliform inactivation by UV-radiation in a pilot-scale real-life aquaponic system.

Lettuce (Lactuca sativa L.) is an important vegetable crop that can be grown in hydroponic and aquaponic systems. A comparative study to evaluate the efficacy of a cold water flow-through aquaponic system (FTS) to a hydroponic system is lacking. Twenty-seven lettuce cultivars with green or red leaves, in seven subtypes, belonging to four popular types in the Western diet, were grown in spring water or aquaponic or hydroponic treatments. Spring and aquaponic water flowed directly from a spring and a raceway growing rainbow trout, respectively. The hydroponic treatment had nutrients added to a recirculated system. Stand establishment, average yield, and productivity (yield/week) were determined for each subtype or cultivar and compared among water treatments. No comparison among lettuce types, subtypes, or cultivars was made due to inherent differences among genotypes. Total yield and productivity (402.5 g·m−2 and 4.9 kg/tray/week, respectively) in the FTS were lower than those in the hydroponic system (468.9 g·m−2 and 6.7 kg/tray/week, respectively). Average yields of butterhead and bibb subtypes in aquaponics were higher than in the hydroponic treatment. Bibb subtype lettuces performed better in the aquaponic treatment, and average yields of butterhead and romaine, one of the most popular and nutritious lettuce types, were similar to those in the hydroponic treatment. The cvs. Outredgeous in romaine, Winter Density in bibb, Red Sails in leaf, and Red Saladbowl in oakleaf subtypes were recommended for an FTS. Average yields of green lettuces were higher than red lettuces in the bibb subtype in all treatments. Lettuce yield, depending on cultivar, could be comparable to hydroponic or field production based upon yield per area.

Aquaponics is the combination of hydroponics and aquaculture that sustainably produces both animal and plant food products. Soluble nutrients are released into water by the fish providing nutrition for plant growth. Lettuce (Lactuca sativa L.) is one of the most popular vegetables grown in aquaponic systems. In this experiment, the feasibility of year-round lettuce production utilizing a cold water flow-through aquaponic system (FTS) growing trout (Oncorhynchus mykiss) in a high tunnel was evaluated. A high tunnel is a greenhouse-like facility constructed with polyethylene covering a metal frame which extends the growing season and protects the crop from cold temperatures. The average night air temperature inside the high tunnel during winter in Wardensville, WV was 2.9±3.4 °C and it helped extend the growing period into the fall and winter. Results from this pilot scale experiment showed the potential for year-round lettuce production in an FTS. Average yield (fresh harvest weight per tray) in the spring season was the highest, while productivity (average yield per week) during the summer season was higher than that in spring. During the extended growing seasons (fall and winter), more than a quarter (30.6%) of the total lettuce production was obtained. The yield per unit area (7.4 kg m-2) from our pilot study was significantly higher than that from the reported average field production (3.1 kg m-2) in the U.S. except California and Arizona where year-round production of lettuce occurs. To compensate for lower lettuce yields during cold seasons, high value crops requiring less nutrients and tolerant to the colder environment may be considered.

This study examined the establishment and growth performance of 34 food crops grown in a cool, low nutrient aquaponic system. Process water from a spring-fed flow-through trout raceway, with an average fish biomass of 3630 kg, was used as the water and nutrient source for the plant growing operation. Process water temperature entering the plant growing channels was 13 degrees C with average concentrations of 0.35, 0.34 and 0.19 mg.L-1 for ammonium, nitrate, and phosphate, respectively. Crop types included lettuce, Asian greens, mustards, other greens, vegetables and herbs. Stand establishment (percent filled cells) and harvest and individual biomass were evaluated under three treatments; low flow (18.9 L/min), high flow (75.7 L/min), and an amended high flow treatment. The amended high flow treatment consisted of vermiculite planting media amended with composted fish waste and was placed in a channel receiving high flow. These treatments represented a gradient of nutrient availability with low flow receiving the fewest and the amended high flow treatment receiving the most nutrients. Due to space constraints cultivars were sown in two sets. Cultivars in set two were sown as space was made available when cultivars from set one were harvested. Stand establishment was greater than 80% for most cultivars under all treatments. However, the herbs sage, garlic chives, and lovage had poor stand establishment as did the vegetables Swiss chard and beets, which were sown late in the study. For most cultivars, stand establishment was not significantly different among treatments. The majority of cultivars attained the lowest biomass on the low flow treatment. Notable exceptions were cilantro, parsley, and minutina. Eight cultivars, including kohlrabi and the bibb lettuce 'Rex', grew best on the high flow treatment. The remaining 21 cultivars realized the greatest biomass on the amended treatment although in many cases the increase in biomass was minor. Additionally, for some cultivars, significant increases in stand establishment offset decreases in growth. Minimal improvements in water quality were observed, probably as a result of nutrient mobilization from accumulated solids within the aquaponic channels.Statement of relevance: Many producers want to produce aquaponic crops but little basic information such as provided in this study is available about stand establishment, expected harvest biomass, or time to harvest making this study extremely relevant to commercial aquaculture. (C) 2016 Elsevier B.V. All rights reserved.

Aquaponics is an integrated food production technology of aquaculture and hydroponics. Lettuce (Lactuca sativa L.) is an economically important vegetable crop that can be grown aquaponically. In addition to selecting the right choice of lettuce cultivars, developing an optimal harvest strategy could increase lettuce production. Lettuce production using two harvest methods, Cut-and-Come-Again (CC) and Once-and-Done (OD), was evaluated using ‘Red Sails’ lettuce in a flow-through aquaponic system rearing trout. With the CC method continual harvesting was possible on a weekly basis after the initial harvest, while it took five weeks for each harvest using the OD method. The total yield of lettuce by the CC method was 6.7 kg from 9 trays, while 22.6 kg of lettuce was harvested by the OD method using 54 trays. In harvests by the OD method, 6 times as many seeds were sown compared to the CC method. The average yield per tray harvested by the CC method (744.4 g/tray) was 78% higher than that by the OD method (418.5 g/tray) because the CC method used 6 times less trays. Productivity, calculated by the average yield per growing week, of the two harvest methods at the first harvest was similar, but 4.8 times higher in the CC method than in the OD method at the second harvest due to the shorter harvest time. However, visual and decay ratings of lettuce harvested by the CC method began to decline afterwards. Together, the OD method after two consecutive harvests by the CC method would help growers to obtain increased yield of quality lettuce.

Brook trout (Salvelinus fontinalis) populations are threatened by introduction of invasive species, habitat loss, and habitat degradation in their native range and are a problem invasive species in western Unites States and Canada and in Europe. Stocking sterile triploids has been promoted as an approach to reduce negative effects of stocking of brook trout for recreational fishing on native fish populations. Crossing a tetraploid with a diploid is a method of triploid production that may help hatcheries meet demand. We induced tetraploidy in brook trout by application of 633 kg·cm−2 of hydrostatic pressure for 8 min at 70%–72.5% of the first cleavage interval. Yields of above 50% tetraploid progeny at hatching were readily achieved, although few animals reached 1 year of age. We crossed a male tetraploid with female diploid fish and produced interploid-triploids with eyeing rates in excess of 50%, demonstrating male tetraploids are fertile and capable of siring triploid progeny. Female tetraploid fish were reared to 16 months posthatching and possessed follicles in secondary vitellogenesis, suggesting tetraploid females are also fertile. Tetraploid induction rates in excess of 96% were achieved applying the same hydrostatic pressure treatment to zygotes of tetraploid × diploid crosses at 30 min postfertilization.

Solids management plays an important role in the optimal aquacultural production and water quality improvement. The geotextile bag filters (GBFs) were used to dewater biosolids from flow-through aquacultural raceways in this study. Jar tests and geotextile cone tests were conducted to determine the polymer flocculant and its optimum dose for GBF application. In the meanwhile, the effect of GBFs on soluble nutrients (N&P) and BOD 5 was also evaluated. The solids content in the raw sludge generated from the flow-through aquacultural raceways in this study was highly variable ranging from 234 to 4290 mg/L (or 0.02 to 0.43% solids). GBFs was very effective in capturing the solids in the aquacultural sludge from flow-through raceways and the addition of Hyperfloc 626 polymer improved the solids removal by GBFs from 87.1±6.9% to 97.3±1.9%. Geotextile bags also effectively removed BOD 5 from the aquacultural sludge and enhanced removal (83.9±2.2%) was observed with polymer addition. On the other hand, the concentrations of soluble nutrient species (N and P) in the geotextile bag filtrate were higher than those in the raw sludge as a result of the decomposition of the particulate organic matter in the geotextile bags.

Chapter 36 Sustainable Aquaculture Using Treated and Untreated Mine Water from Coal Mines Kenneth J. Semmens, Kenneth J. SemmensSearch for more papers by this authorJames A. Jacobs, James A. JacobsSearch for more papers by this author Kenneth J. Semmens, Kenneth J. SemmensSearch for more papers by this authorJames A. Jacobs, James A. JacobsSearch for more papers by this author Book Editor(s):James A. Jacobs, James A. JacobsSearch for more papers by this authorJay H. Lehr, Jay H. LehrSearch for more papers by this authorStephen M. Testa, Stephen M. TestaSearch for more papers by this author First published: 25 April 2014 https://doi.org/10.1002/9781118749197.ch36 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary Water is a valuable by-product of the coal industry. Although it may be considered "impaired," other industries can and do make use of it. Aquaculture requires significant volumes of water and show promise. Treated water originating from coal mines in the eastern U.S. Appalachian Mountains has been used to produce rainbow trout in an economical manner for almost two decades. This chapter summarizes the systems that were utilized over a period of about 10 years. Five case studies are examined for activities that occurred over the past 10 years. Net pens and raceways have been used at three acid mine discharge treatment plants. Each of the five case studies representing fish farming projects in three eastern states (West Virginia, Maryland, and Pennsylvania), illustrate a different aquaculture production system, each having advantages and disadvantages. Acid Mine Drainage, Rock Drainage, and Acid Sulfate Soils: Causes, Assessment, Prediction, Prevention, and Remediation RelatedInformation

An acoustic Doppler velocimeter (ADV) was used to measure detailed vertical profiles of mean velocity and (for the first time) turbulence characteristics at the center of the quiescent zone (QZ) of operating aquaculture raceways. Instantaneous velocities were recorded at 10 Hz and averaged over a 360-s time interval in order to derive mean velocities, root-mean-square velocities, and turbulence intensities. The type and cleanliness of the screen separating the QZ from the fish rearing zone was found to be significant. When screens are free of growth and debris, smaller screens promote more uniform mean streamwise velocity profiles, reduce the streamwise root-mean-square (rms) velocities near the floor, and greatly reduce the turbulence intensities in the lower half of the profile. These effects suggest that smaller screens may be used to enhance the setting efficiency of QZs, but this conclusion may not be valid when the screen accumulates significant amounts of debris and algal growth. This condition dramatically alters both the magnitude and the shape of the mean and turbulence profiles. The slower mean velocity produced by a dirty screen should tend to enhance settling, but the higher turbulence has the opposite effect. It is not clear which effect is dominant. The resolution of these questions will require more comprehensive measurements of velocity and solids concentration. (C) 2013 Elsevier B.V. All rights reserved.

To study the influence of genetics and feeding strategy, we measured growth and mRNA expression of protein degradation markers in growth‐selected and control rainbow trout that were either fed to satiation or limit‐fed. Fish were limit fed to 90–95% of the feed required to reach maximal growth. Length and weight of 1600 trout were measured every six weeks for 24 weeks. After 24 weeks of dietary treatment there was an interaction (p<0.05) between genetics and feeding strategy for both length and weight. The least squares means ± the standard error of the means for weight of satiation/control, limit‐fed/control, satiation/selected and limit‐fed/selected fish were 371 ± 6, 350 ± 4, 544 ± 24, and 426 ± 16 grams and for length 299 ± 2, 291 ± 2, 347 ± 2 and 330 ± 2 mm, respectively. mRNA expression of 4 components of the ubiquitin/proteasome machinery were decreased (p<0.05) by an average of 17% in muscle of the growth‐selected fish consistent with a reduced capacity to degrade protein. No effect of feeding strategy was seen for mRNA expression nor was an interaction detected. No differences in IGF‐1 concentrations were detected due to feeding strategy or genetics. This suggests decreased degradation of protein through proteasomes and caspases could be the cause for increased weight and length of the growth‐selected trout. Support: Aquaculture Product and Marketing Development Project.

The effects of dietary modification with flaxseed oil-enhanced (Flax) feed on the product quality of brook trout fillets were examined. Trout were fed a commercial feed supplemented with fish oil (CD) or flaxseed oil (Flax) for 165 d before harvesting. Proximate composition and fatty acid profile were determined on fillets. Quality parameters of the raw fillets were examined over the storage period by measuring color (L*, a*, b*), muscle pH, and thiobarbituric acid reactive substances test. Evaluations on the cooked fillets included sensory evaluation with triangle tests and a paired preference test. There were no differences in proximate composition between the groups; however, the total omega-3 fatty acids were greater in Flax fillets (P<0.05). Diet and day were shown to interact in their effect on whiteness, pH, and lipid oxidation (P<0.05); however, linear regression did not determine that malondialdehyde concentration was associated with time in either diet type implying that lipid oxidation in the vacuum-packed fish was controlled at storage temperatures (4°C). Sensory panelists were able to choose the odd sample in a replicated triangle test analyzed using the β-binomial model, and there was preference for Flax fillets (P<0.05). Results indicate that a Flax-enhanced diet would have favorable effects on product quality of farmed brook trout.