Evaluation of Yellow Perch Grow-out in a 19oC RAS Gregory Fischer, Chris Hartleb, James Held, Kendall Holmes, Sarah Kaatz, & Jeff Malison

HISTORY Yellow Perch are an important commercially raised coolwater fish in the Midwest Raised for food markets and stocking uses in outdoor ponds and recirculating water systems Fillet prices range from $18.70 to $37.40/kg depending on market Market size within 12 months is desirable Issues with initial larvae feeding for commercial rearing in RAS Issues with cold water temperatures during winter for outdoor rearing in ponds

Materials and Methods Conduct pilot study to evaluate the effectiveness of combining early outdoor pond rearing with indoor RAS for yellow perch grow-out to meet the needs of the food fish market. NADF acquired Lake Mendota strain, pond raised, feed trained, fingerling (avg127 mm) yellow perch (monosex female and mixed sex). Project conducted inside main Aquatic Barn in Bayfield, Wisconsin

Materials and Methods 49,394 L(13,000gal) Grow-out system consisted of: Culture tanks: Four 1.4m³ (1,500L) (400 gal) Two 5.7 m³ (5,693 L)(1,500 gal) Two 10.8 m³(10,757L)(2,800 gal) Drum filter, fluidized sand biofilter, carbon dioxide stripping column w/fan, oxygen cone and UV treatment unit. Average water flow was 1,480L/min. Replacement water 4.7L/min (<1% Total Flow)

Materials and Methods Tanks were partially covered with foam board Fish were fed Nelson Silver cup extruded feed (46% protein, 16% lipid) daily with automatic vibratory feeders Photoperiod was controlled by timers and lights to provide12-16 hours daily Tanks were cleaned and monitored daily

Materials and Methods Dissolved oxygen (mg/L), temperature (ºC), and total dissolved gases (%) were measured daily in each tank (Common Sensing Model TBO-DL6F Gas Meter, Common Sensing Inc., ID). pH was monitored daily in each tank (Pinpoint pH meter, American Marine Inc, CT). Ammonia-nitrogen (NH3-N), nitrite-nitrogen (NO2-N), and reactive phosphorous (PO4) were measured (CEL 850 Hach Test Kit, Hach Inc., CO) weekly from water samples collected in the RAS sump according to standard water quality methods (APHA, 1989). Yellow perch length and weights were measured monthly by obtaining 50 randomly sampled trout from each tank.

Mixed Sex Yellow Perch Water Quality and Mortality Results Mixed Sex Yellow Perch Water Quality and Mortality

Monosex Female Yellow Perch Water Quality and Mortality Results Monosex Female Yellow Perch Water Quality and Mortality

Results Measured Ammonia-nitrogen (NH3-N) and Nitrite-nitrogen (NO2-N) in the Yellow Perch RAS system

Results-Fish Performance Lake Mendota Yellow Perch Mixed Sex and Mono-Sex Monthly Length Increase

Results-Fish Performance Lake Mendota Yellow Perch Mixed Sex and Mono-sex Monthly Weight Increase

Results-Fish Performance Condition factors were considered excellent for both groups (monosex fish were 1.412 and 1.393 for mixed sex fish) Filet yield averaged 47.8% for all groups Tank densities at harvest were 26kg/m³ for mixed sex fish and 44kg/m³ for monosex fish Total mortality was 28% for mixed sex fish and 0.6% for monosex fish

Results-Estimated Production Costs Calculated system operating cost without capitol cost was $2,179/month based on commercial utility rates ($0.08/kw/hr) and estimated labor. The actual operating cost at NADF was $1,432/month based on an electrical rate of $0.04/kw/hr. This translates into $0.183/L and approximately $3,940 for 6.3 months of operation for two 10,757 L (10.8 m3 )tanks. Total of 919 kg of feed at an average cost of $970 ($1.06/kg) was used during the study. Total estimated production costs, not including capital & fingerling cost, was $4,910. Based on a market value of $5.50/kg(2.50/lb), the total approximate value of yellow perch raised in the system was $5,550.

Conclusion Lake Mendota mono-sex female yellow perch can potentially outperform Lake Mendota mixed sex yellow perch in a 19ºC water RAS. 127 mm(5inch) fall pond fingerlings can be finished successfully for market in approximately 190 days in a indoor RAS system. Additional research and replicated studies are needed to further investigate grow-out of various strains of yellow perch in RAS and the cost effectiveness of such systems.

Acknowledgements We thank Peter Fritch of Rushing Waters Trout Farm for his involvement and interest in this project. Jeff Taylor and Nate Wendt of Star Prairie Trout Farms were also helpful throughout this project and provided important information regarding fish production and processing. We would also like to acknowledge the efforts of technicians Kendall Holmes, Dan Duffy, and summer interns Abby Purdy and Ryan Huber at the UWSP-NADF for fish rearing and data collection. Steve Summerfelt of Freshwater Institute provided valuable review comments and technical assistance. This project was supported by NADF base funding. Mention of trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty and does not imply approval to the exclusion of other products that may be suitable.

NADF Webpage: http://aquaculture.uwsp.edu QUESTIONS?????????????? Contact Information: Gregory Fischer, Facility Manager 715-779-3461 gfischer@uwsp.edu NADF Webpage: http://aquaculture.uwsp.edu