Producing Hybrid Walleye in a Commercialscale Water Recirculating System
Gregory Fischer, Facility Manager
Kendall Holmes, Advanced Aquaculture Technician
UW-Stevens Point
Northern Aquaculture Demonstration Facility
Why Hybrid Walleye(Saugeye)???
Hybrid walleye have many characteristics that lend themselves to
aquaculture production intensively.
Ability to raise and spawn broodstock intensively and out of
season.
Ability to do entire rearing cycle intensively from egg-fry-fingerlingmarket size fish on commercially available feeds. (no plankton or
brine shrimp needed!!!).
Growth rates up to 2.0grams per day (3-4x better than yellow
perch!!).
Good feed conversions (1.2-1.4) during growout.
Existing markets in the Midwest and good fillet market prices ($1012 lb).
Potentially several market sizes from petite fingerlings in <6months
to larger sized fish in 1 to 3 years.
Good rearing temperatures and water quality for possible
aquaponics
Objectives
The UWSP-Northern Aquaculture Demonstration Facility (Bayfield, WI)
conducted a three year pilot project to evaluate and demonstrate
commercially available new technologies for producing purebred and hybrid
walleye for stocking and food fish.
The project consisted of different areas including:
1) Intensive production and seasonal advancement of walleye and sauger
broodstock.
2) Production of large walleye (>300mm)(12inch) on commercial feed for
NR stocking.
3) Production of hybrid walleye to food market size(454g)(1.0 pd) using
intensive rearing and recirculation systems.
Materials and Methods
Experimental Tank Setup for
Phase I-II Intensive Rearing
•230 L (60 gal) round tanks
•Sidewalls painted black
•Gray bottom
•Adjustable lighting
•Directional flow-thru
20ºC(70ºF) water (2-6 lpm)
•Clay(old mine #4)
•24 hr feeders
•Surface spray
•Removable screens
•Daily cleaning system
Water inflow pipe
Surface
spray
Directional water flow
Center screen
Feeder
Otohime fry feed
200 -1400 m
Nelson Silvercup
walleye grower
1.0mm
Materials and Methods
Recycle System Used For Phase III-IV Intensive Growout
RAS Parameters:
•53,000 L water capacity
•33 m³ tank culture space
•Fluidized sand biofilter
•Drum Filter
•Dual drain circular tanks
•Oxygen cone
•In sump electric heater
•23ºC (74ºF)Water temp.
Results
Overall Survival Percentages
Intensive Rearing
100
90
0-38 mm
Phase III
80
38-51 mm
% survival
70
Phase II
51-102 mm
60
50
Phase I
102-152 mm
40
30
48%
48%
>90%
20
10
0
Phase and fish length
152-239 mm
Results
Phase II-Fry Culture
Average Survival Phase I Fry at Different Densiities
45.0%
39%
40.0%
35.0%
% survival
30.0%
25.0%
20.0%
low density
high density
16.7%
15.0%
10.0%
5.0%
17fry/L
46fry/L
0.0%
Rearing Density
Results
Phase 1- Fry Culture
Observed Phase I Fry Mortality
45
41%
40
Overall mortality %
35
30
25
18%
20
15
10
5
0
Low Density
High Density
Walleye/Hybrid Walleye: Cannibalism
•Starts immediately
•Unobserved mortality
•Can account for low survival
rate in ponds and in indoor
tanks
Results
Phase 1- Fry Culture
Unobserved Phase I Fry Mortality ie. Cannibilism
60
51%
Overall mortality %
50
40
33%
30
20
10
Low Density
0
High Density
Results
Phase II Fingerling Rearing Survival %
100.0%
90.0%
93.5%
80.0%
% Survival
70.0%
60.0%
low density (9 days)
50.0%
38.9%
40.0%
30.0%
20.0%
10.0%
2.3 f/L
9.9 f/L
0.0%
Rearing De nsity and Days in Tank
high density (13 days)
Results
Growth Rates
H y b rid Wa lley e v s P u reb re d Walle y e G ro w th in Weig h t
450
Phase II
Phase I
Early Lifestage
Rearing
400
350
Phase III
Growout in Recycle System
G ra m s
300
250
200
S E -10
S E -09
150
WE -10
WE -09
100
50
0
366
346
317
288
262
251
228
222
Nov
201
D a y s P o s t Ha tc h
197
Aug
187
173
170
159
156
142
129
127
116
105
98
91
85
73
June
67
64
58
52
37
29
20
April
March
1 year old Hybrid Walleye (1.0kg)
Results
Hybrid Walleye Feed Rates and Conversion Ratio
20
20
18
15
16
14
12
10
7.5
8
7
6
4
4
2
2
0
2
TBW FD(%)
1.6
1
2
Grow th Phase
FC
3
4
Recycle System Water Quality
Operating Parameters
Parameter
Average Value
Temperature (ºC)
23
Dissolved oxygen (mg/L)
>7.0
pH
7.7
Carbon dioxide (mg/L)
6.8
Total ammonia nitrogen (mg/L)
0.011
Nitrite nitrogen (mg/L)
0.061
Calculated unionized nitrogen (mg/L)
0.0003
Total suspended solids (mg/L)
2
Alkalinity (mg/L)
151
Commercial Intensive Production
Recommendations
• Phase I
High density/shorter time frame in tank
Water Temperature: 20ºC
Density: 30 days @ 46 fry/L
Feed: Otohime
TBWFD: >20% @ 24hr
*Grade in tank every week as
soon as possible from Phase I-III.
• Phase II
Water Temperature: 20ºC
Density: 10 days @ 4 fish/L
Feed: Nelson SC Walleye Grower
TBWFD: >15% @ 24hr
Production Recommendations
• Phase IIb-Intensive Culture
Water Temperature: 20ºC
Density: 4 fish/L
Feed: Nelson SC WG
TBWFD: 6-10% @ 24hr
• Phase IV-Growout
Water Temperature 23ºC
Density: 70kg/m³
TBWFD: 1.5-2.0% @ 24hr
Feed: Nelson SC WG
Conclusion
• NADF recycle system
produced market size (avg.
454g) hybrid walleye in 316
days from fingerling (avg.
0.95g) at average tank
densities of 34kg/m³.
• Walleye and hybrid walleye
can be successfully raised
indoors using early advanced
spawning, incubation, and
rearing techniques.
Conclusion
• Initial data suggests that
growth rates of hybrid walleye
are higher than purebred
walleye.
• Processing yields of >50%
and initial marketing studies
indicate good aquaculture
potential and high demand for
hybrid walleye as food fish.
Acknowledgements
We would like to thank Alan Johnson at the Rathbun Fisheries Research Center
in Iowa for all his assistance and guidance. We would also like to acknowledge
the efforts of NADF technicians Lance Bresette, Nate Martin. Dr. Chris Hartleb
(Co-director) and Jim Held(Extension) have also provided assistance and
guidance throughout this project.
This project was supported by an Agricultural Development & Diversification
grant through the Wisconsin Department of Agriculture, Trade and Consumer
Protection.
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.
QUESTIONS??????????????
http://aquaculture.uwsp.edu
[email protected]