Progress 09/01/23 to 08/31/24
Outputs
Target Audience:Stakeholders directly affected by this research include hatchery managers, owners, and their hired personnel. Other parties involved includeresearch and Extension faculty members, graduate students, undergraduate students, and research staff of Auburn University, who wereresponsible for conducting each of the proposed experiments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training activities - Graduate students directly involved in this USDA-NIFA project (1 MS and 1 PhD) and other student helpers (3 MS and 1 PhD) in theAquatic Reproductive Physiology and Hatchery Science Lab at Auburn University(PI: Butts) learned fundamental concepts in aquatic reproductive biology/physiology, hatchery science, larval fish nutrition, gene expression, experimental design, and data analyses. Specifically, they gain hands-on training (one-on-one work with a mentor) in fish husbandry; broodstock management; and culturing of rotifers (Brachionus plicatilisandBrachionusrotundiformis),Artemia sp.andmicroalgae (Isochrysissp., Tahitian strain (TISO) andPavlova lutheri). They were also responsible for building, operating, and maintaining flow-through and recirculation systems and monitoring lab equipment and water quality (dissolved oxygen, pH, temperature, salinity, saturation, NH3, NH4, NO2,Cl2). Students also played an integral role in conducting and designing experiments; supervising undergraduate students; ordering laboratory supplies; and maintaining up-to-date standard operating procedures and material safety data sheets. Professional development -Graduate students (1 MS and 1 PhD) are now conducting individual studies for their thesis projects [chair: Butts (PD); committee members: Bruce, Roy (co-PDs)]. This includes studies on aquatic hatchery science, molecular physiology, and nutrition. How have the results been disseminated to communities of interest?A. Cletzer wrote an article about our largemouth bass research for the Auburn University website (section:Research and Innovation Stories) titledAuburn hatchery scientists take on a project to help U.S. largemouth bass producers(6 Dec 2023;https://agriculture.auburn.edu/research/hatchery-scientists-take-on-project-to-help-u-s-largemouth-bass-producers/?utm_source=web&utm_medium=auburn-stories-research). Three scientific papers are currently In Preparation from this work, which will be disseminated to the scientific community and stakeholders. Bernal, M.A., Aguilar, G.L., Sakmar, J., Politis, S.N., Oglesby, S.L., Nicholls, A., Kelly, A.M., Roy, L.A., Butts, I.A.E. Transcriptome analyses reveal differences in the response to warming in Florida and Northern largemouth bass (Micropterus spp.) during early life stages.To be submitted in Fall 2024 Parajuli, N.S.,Sakmar, J.,Nicholls, A.,Martin, K.A.,Liyange, S., Wood, K.R.,Swanepoel, A.,Kelly. A., Roy, L., Bruce, T.J.,Butts, I.A.E. Predator and prey density impacts largemouth bass performance during early life history when cultured in an indoor recirculation aquaculture system.To be submitted in Fall 2024? Swanepoel, A.,Sakmar, J.,Nicholls, A.,Parajuli, N.S., Goodman, D., Martin, K.A.,Liyange, S., Wood, K.R.,Kelly. A., Roy, L., Bruce, T.J.,Butts, I.A.E. Impact of tank color and light intensity on early larval development in largemouth bass.To be submitted in Fall 2024 What do you plan to do during the next reporting period to accomplish the goals?During Fall 2024 and Spring 2025, we will look at the impact of photoperiod on the growth and development of LMB and developearly weaning strategies during early ontogeny. For the photoperiod study, the hatchery-reared fish will be reared under three different photoperiods: 12-hour light/12-hour dark, 16-hour light/8-hour dark, and 24-hour light/0-hour dark. Conditions will be replicated across three tanks per treatment. All other conditions will mimic optimal conditions observed in our completed studies. Data collection - Growth and morphology, gut fullness, weight, deformities, and targeted gene expression will be quantified. For the weaning study, we willdetermine the necessity of rotifers and theearliest time to wean fry onartificial diets. For methods, yolk-sac fry will be stocked into tanks and reared in an RAS using our top fry stocking density prey density combination, light regimen, and tank color. Fish will be factorially administered eight different dietary treatments, each with three replicate tanks. Treatments 1-4 will be fed freshwater rotifers,Brachionus calyciflorus(fed microalgae and ORI-One from Skretting) at 10 rotifers/mL from2 to 5DPH. Those fry will also receive liveArtemiafrom 2 to 5 DPH (Treatment 1), 2 to 10 DPH (Treatment 2), 2 to 15 DPH (Treatment 3), and 2 to 20 DPH (Treatment 4). Meanwhile, Treatments 5-8 will only receive liveArtemiafrom 2 to 5 DPH (Treatment 5), 2 to 10 DPH (Treatment 6), 2 to 15 DPH (Treatment 7), and 2 to 20 DPH (Treatment 8). All fish (Treatments 1-8) will be gradually transitioned onto an artificial diet for 60 hours before eliminating all live feed; after that receiving only an artificial diet to 28 DPH. The control group (Treatment 9) will only receive an artificial diet. Growth and morphology, weight, deformities, targeted gene expression, and larval gut fullness will be quantified.
Impacts
What was accomplished under these goals?
Our team started collecting data in January 2024. Since then, we have made great progress, completing fish data collection for two experiments. Our progress is outlined below: Exp. 1- Effects of initial yolk-sac fry stocking density and prey density (Artemiaspp.) on industry-relevant offspring performance traits.Objective- Determine initial yolk-sac fry stocking density, prey density, and stocking density x prey density interactionthat increases the efficiency of largemouth bass (LMB) hatchery production. Experimental design- Northern LMB embryo cohorts were collected from Red Hills Fishery and transported to SFAAS, where they were reared at ~21oC. At peak hatch, yolk-sac fry from each replicate cohort was placed into blue tanks equipped with recirculation aquaculture system (RAS) technologyand slowly acclimated to 25-26oC. The RAS had30 blueaquaria,3 × 794 L circular blue tanks, 2 × 190 L sump tanks, UV sterilizer, mechanical filter, fluidized bed biological filter, and temperature control (heat pump). Yolk-sac fry from each replicate cohort was stocked in RAStanks at densities of 25, 50, and 100yolk-sac fry/L.Starting at 3 days post-hatch (DPH), fry from each stocking density were factorially fed Premium GradeAArtemiaat 2, 4, and 8Artemia/mL every 2 h from 07:00 to 23:00. In total there were 27 experimental tanks (3 stocking densities× 3 prey densities × 3 replicateembryo cohorts). In addition, an artificial diet was added to each tank starting at ~120degree-days until 26 DPH.Mortalities, excess feed, and fecal matter were removed daily. Rearing of offspring took place under a 12-hour light/12-hour dark photoperiod at ~250-400 lux. Handling and sampling were done under low-intensity light conditions. Water quality variables were monitored daily to ensure they remained within acceptable ranges.Data collection-Growth and morphology: At peak hatch (time 0), 10-12 individuals were randomly sampled from each tank. After that, fish (n = 10-12) from each tank were sampled at various developmental landmarks during early ontogeny (7, 14, 21, 26 DPH). Fish were anesthetized or euthanized using buffered M2-222 before handling. Digital images were taken of each fish using a Zeiss SteREO Discovery V12®microscope equipped with a Zeiss Axiocam 305 camera, with measurements extracted using Zeiss imaging software. Total length, notochord length, yolk-sac area, eye diameter, jaw length, myotome height, and body area were obtained for each individual. For each fish,gut fullnesswill be calculated as the percentage of food particles relative to the total gut area.Classification of deformities: Fish (n = 10) from each aquarium were sampled and visually inspected under a Zeiss SteREO Discovery V12®microscope and classified into the following deformity groups: pericardial (edema), head (deformed head shape), eye (no eye/abnormal eye), yolk (abnormal lobe shape), tail (bent, curled, or missing), and spine (bent curvature). The rate of deformities (%) will soon be calculated.Targeted gene expression: To further understand phenotypic sensitivity to predator (fish) and prey density, we will follow the expression of targeted genes previously reported to be associated with stress tolerance, growth, anddevelopment.Relative gene expression between the stocking density groups will then be assessed using theDDCt method. Our preliminary data shows promising results, with increased survival (up to 80%) and growth at the lower larval stocking densities and higher prey densities. Exp. 2- Effects of light regimen and tank color on industry-relevant offspring performance traits.Objective-Determine the light regimen and tank color that increases the hatchery production efficiency.Experimental design- Tank color and reflectance influence light dispersion and subsequent prey detection within a tank. Thus, these factors are relevant for enhancing the production of LMB. Embryos (represented by ~8-10 families) were transported to SFAAS, where they were incubated at ~21oC, while larvae and fingerling rearing temperatures were adjusted to27oC.Tanks were stocked (50 yolk-sac larvae/L)andfed live feed and an artificial diet.Fluorescent white light (full spectrum approximating natural sunlight at 5000 K) was provided to all rearing tanks. At peak hatch, yolk-sac larvae were transferred to a RAS system equipped with 30 × 15 L circular tanks. Here, the effect of light intensity (400 and 800 lux; both measured at the water surface) and tank color(black, blue, red, green, white) weretested using a 2 × 5 factorial design with three replicate tanks per treatment. Photoperiod was 12-hour light/12-hour dark.Data collection-Growth and morphology,gut fullness,weight,deformities, andtargeted gene expressionare now being quantified.Preliminary results- No significant differences were observed between different tank colors or light intensities for final weight and biomass. Black tanks produced a significantly higher survival of 77.45% compared to white, red, and green tanks which were 63.25, 67.33 and 66.23% respectively, and no difference to blue tanks which showed a survival of 71.9%. Black tanks showed a significantly lower cannibalism percentage of 0.06% compared to red and white tanks which had a cannibalism percentage of 0.14 and 0.21% respectively and no difference to blue and green tanks at 0.12 and 0.15% respectively. In terms of different light intensity lux levels, no differences were observed for survival or cannibalism.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2024
Citation:
Butts, I.A.E.. 2024. Aquatic Reproductive Physiology and Hatchery Science Lab. 8th Fish and Shellfish Larviculture Symposium. Ostend, Belgium (Poster presentation)
- Type:
Other
Status:
Published
Year Published:
2024
Citation:
Butts, I.A.E., Parajuli, N., Swanepoel, A., Roy, L., Kelly, A., Bruce, T., Davis, D.A., Kwasek, K.A., Nicholls, A., Sakmar, J. 2024. Development of intensive indoor rearing strategies for largemouth bass during critical early life history stages. NIFA-USDA Annual Growth and Lactation Program Project Director Meeting. Calgary, Canada (Poster presentation)
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