Performing Department
(N/A)
Non Technical Summary
The proposed project will directly support yellow perch (Perca flavescens) aquaculture through development of new larval/juvenile rearing technology and documenting the presence of off- odors and taints in the final fillets. Availability of feed trained yellow perch juveniles currently limits the capacity of intensive, indoor culture operations to obtain marketable size perch.Current perch culture methods during this critical period resulted in past low survival (<10%) and heterogenous fish size (cannibalism). Indoor intensive culture of yellow perch larvae has been developed and successfully used at the OSU Aquaculture Laboratory in a specialized recirculating aquaculture system. This system maintains conditions of elevated salinity and algal turbidity with high live food density (marine rotifers and brine shrimp) and regularly achieves 60-70% survival and 60-65% swim bladder inflation at high stocking densities (30-40 larvae/L). We will also enhance consumer acceptance of cultured perch by minimizing taints produced during production. Indoor culture operations can produce conditions where geosmin and 2-methylisoborneol, the most important taints in freshwater fish, build up in the fish muscle. Fish will be grown out in different recirculation systems at two commercial facilities and the resulting fish studied to determine conditions which prevent production of off-flavor taints in the fillets. Improved growing conditions and insight into the fillet quality will expand the marketability potential of cultured perch and have the potential to be applied to other commercially important percid species.
Animal Health Component
40%
Research Effort Categories
Basic
15%
Applied
40%
Developmental
45%
Goals / Objectives
GoalsThe primary goals of this project are to develop technology for production of early stages of feed-trained yellow perch and to evaluate and improve fillet quality to expand and diversify the current yellow perch market. The proposed technology will be up-scaled based on laboratory findings and will strengthen existing grow-out practices, increasing the potential availability of highquality, feed-trained juveniles, year-round at various scales of production. To ensure the 'finished product' is of high quality and marketable, the proposed research on fresh fillet quality will provide new insight into the effects of RAS on off-odors, identifying causes and providing solutions to amajor issue experienced by the aquaculture industry. Thus, resulting knowledge and technology will have applications for other commercially important species, such as walleye Sander vitreus, tilapia Oreochromis sp., and largemouth bass Micropterus salmoides.ObjectivesEvaluate the use of modified 'filter and sprayer recirculating setups' (FSRS) in different sized tanks at the OSU Aquaculture Laboratory facility. Growth, survival, and swim bladder inflation of yellow perch larvae/juveniles after 14 (live food) and 28 days of feeding (including formulated diet) will be evaluated (years 1 & 2, Dabrowski).Evaluate the efficacy of modified FSRS set-up in existing culture tanks at Fresh Harvest Farm, OH (Jeni & Doug Blackburn) and PepperBoy Hatchery, Green Bay, WI (Topher Jacobson) to produce cohorts of feed-trained juvenile yellow perch. Cohorts will then be grown-out to market size at each facility following their routine culture methods (years 1 & 2, Extension & Dabrowski).To use sensory and chemical methods to measure the quality of fillets obtained from two different recirculation systems, ponds, and the wild in order to evaluate the effect of different grow-out technologies on the off-odor taints, lipid characteristics, as well as 'rancid' volatile compounds generated, with a feedback loop to improve grow-out conditions and ensure production of highquality fillets for regional markets (year 2, Barringer & Dabrowski).To transfer the knowledge of improved larvae/juvenile perch rearing technology to aquaculture stakeholders as part of demonstration during workshops and through a variety of outreach products (research and extension personnel, years 1 & 2). To transfer the information of enhanced perch fillet quality and impacts of culture methods on production of off-odor taints and rancid volatiles to the aquaculture industry to improve fillet quality (year 2, Extension, Dabrowski, Barringer).
Project Methods
Objective 1 - In year 1, we will carry preliminary experiments in aquaria system, but the major effort will take place in 2024 when perch larvae will be obtained by controlled reproduction of OSU broodstock. We will evaluate the FSRS within 2 different tank types and water circulation kinetics (cylindrical, flat-bottom 60L tanks and conical, 50L tanks), utilizing 2 fish stocking densities (30 - 60 larvae/L) to determine optimal culture conditions. The FSRS will be installed in twelve 60L flat-bottom cylindrical tanks and twelve 50L conical tanks. Free swimming larvae will be also stocked to 60L cylindrical tanks and 6 of the 50L conical tanks. Another 6 of each tank type will then be stocked at a density of 60 larvae/L. We will compare 2 feeding regimes by eliminatingArtemianauplii, decrease larval feeding cost by determining how time of weaning from live zooplankton to dry feeds affects fish performance. In feeding regime 1, larvae will be provided with live rotifersBrachionus plicatilisfor the 1stweek of feeding, transitioned to brine shrimp,Artemianauplii, for week 2 of feeding, and then transitioned to a high quality commercial dry diet (weaned over 3 days of mixed feeding after 2 weeks of live food, Otohime B2, 360-650μm). In feeding regime 2, larvae will be provided with live rotifers for the 1stweek of feeding and then transitioned directly to a commercial diet (weaned over 3 days of mixed feeding after 1 week on live food, Otohime B1, 150-360μm) over 3 days. Each feeding regime will be tested in triplicate within each tank type stocked with 30 larvae/L and 60 larvae/L. All 24 tanks will be maintained at 3-4 ppt salinity and 10 NTU algal turbidity (Nannochloropsispaste) during the first two weeks of feeding (Grayson and Dabrowski 2023). Then fish will be gradually transitioned to flow-through (no salinity or turbidity) conditions. Fish from all tanks will be sampled after 14- and 28 days of feeding to measure swim bladder inflation rate, survival, and growth (weight, length, specific growth rate %/day). Final sampling will occur once fish reach mean body weight of 0.5g. We will evaluate the impact of tank shape and water circulation (feed distribution and direction of movement), fish density, and time of weaning to formulated feed on perch larvae/juvenile performance.Objective 2General Experimental Conditions - Each site will utilize the FSRS technology described in Obj. 1. Perch larvae will be obtained by controlled reproduction of the OSU broodstock during the spring spawning seasons. If OSU is unable to supply perch larvae, fertilized egg ribbons/first- hatched larvae will be purchased from local producers (W. Lynch, Mill Creek Perch Farm, Marysville, OH). Culture conditions for yellow perch larvae will be the same between the 2 farms: 3-4 ppt salinity, ~10 NTU algal turbidity, ~20-23°C water temperature, live zooplankton feeding at high density (100-300 rotifers/mL, Dabrowski and Miller 2020) for ~2 weeks, and minimum exchange of new water to the system (~1x tank volume/day) - for the first 2 weeks of feeding. A live zooplankton culture (continuous, rotifers and newly hatched Artemia) will be established at each site for feeding larvae. If a system fails or high larval mortality occurs in the first few weeks of culture within the spring spawning season, additional perch larvae will be obtained. Fish in all tanks will be sampled after 14 and 28 days of feeding to measure swim bladder inflation rate and fish size. Survival will be estimated based on volumetric density estimates of initial stocking and daily mortality records. Fish will then be transitioned to dry diet over a period of 3 days of mixed feeding using Otohime brand diet and then grown-out to food-market size (approx. 12-18 months) following the methods routinely used at each facility. Fish growth and survival will be monitored during grow- out through monthly size measurements (to adjust feeding rate) and mortality records. At the end of grow-out, final size and survival will be recorded and fish will be sampled for analyses described in Obj. 3.Objective 3-To evaluate the effect of different grow-out technologies on the deposition of off-odor taints, generation of rancid volatiles, and changes in lipid characteristics of fresh fillets stored on ice, we will sample marketable size yellow perch (150-300 g) from 4 different sources. Perch will be collected from both collaborating facilities that utilized FSRS (Obj. 2), as well as perch grown in intensive pond culture with commercial diet utilization (W. Lynch, Mill Creek Perch Farm, Marysville, OH), and wild-caught fish from Lake Erie (at comparable size and prior to gonad development; Dabrowski and Ciereszko 1996). Fillets (n=20) derived from fish of each of these 4 sources will be weighed and stored fresh, on-ice for 24 hours. Lipids will be extracted, and polar and neutral lipid fractions will be separated and methylated as described by Rinchard et al. (2007) and Grayson and Dabrowski (2020). Fatty acids will be quantified by gas chromatography using a Varian 3900 gas chromatograph (Varian Analytical Instruments, CA). The Thiobarbituric Acid Reactive Substances (TBARS) and Total Volatile Basic Nitrogen (TVB-N) assays will be used to determine the amount of lipid oxidation in the fish samples (Pfalzgraff et al., 1995; Lee and Dabrowski, 2003). In order to identify and evaluate the effect of different grow-out conditions on the generation of taints and 'rancid' volatiles, we will utilize SIFT-MS analysis. Fillets will be subjected to 24 hours of storage time on ice (4°C) prior to analysis. We will measure the volatiles as shown in Smith and Barringer (2014) and Ryo and Barringer (2015). Fillet (30g) samples will be analyzed using a Voice 200™ (V200) SIFT?MS instrument to detect and quantify volatile organic compounds. These analyses will provide first knowledge on production of off-odor taints and rancid volatile compounds in yellow perch fillets produced in intensive indoor systems in comparison to pond and lake grown fish. With this information, we will ensure production of high -quality fillets via these alternative culture systems and expand the marketability of cultured yellow perch as a regional food fish.Objective 4- Technology, including the specialized culture system setup and first feeding protocols, will be transferred using an integrated approach. In Year 1, Extension will document the technology transfer from lab to farm by taking photo and video of FSRS components as installed and operating at Fresh Harvest Farm in Richwood, OH. This documentation will be finalized into a video product in Year 2. In Year 2, a virtual workshop will be delivered, followed by an in-person workshop and field day. The virtual workshop is intended for aquaculture producers and will include topics such as: a general primer on common methods currently employed to produce yellow perch in the Great Lakes region; an overview of yellow perch biology and physiology; economics and marketing; a review of preliminary OSU Aquaculture Laboratory results incorporating the specialized indoor culture system and early life stage feeding protocols; green water technology and transfer of the FSRS technology on-farm.The virtual workshop will be recorded and posted online for those unable to attend live. The in- person workshop and field day will be held at Fresh Harvest Farm in Ohio and will include an overview of yellow perch production methods, a farm/production system tour, a hands-on water quality segment, and an aquatic veterinarian (J. Kieffer, College of VetMed, OSU) to discuss biosecurity and disease prevention measures. Participants will be surveyed to assess knowledge gained, knowledge gaps that remain, major take-aways, changes to current farming practices or production techniques as a result.