Post on 25-Jul-2020
4/9/2014
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Hybrid Walleye (Saugeye)-
The Wisconsin Experience
Jim Held
Aquaculture Outreach Specialist
UW-Extension
jaheld@wisc.edu
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Why Walleye?
High market value
Wide-spread reputation as a food fish
Established fingerling production methods
Limited domestic supply
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Why Not Walleye?
Aggressive behavior
Easily disturbed by shadows and movement
Poor growth rate under intensive conditions
Diminution in growth rate before market size
(especially in males -sexual dimorphism)
+=Bear Deer Beer?
HybridizationThe advantages of some hybrid crosses are very obvious
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With certain fish species, interspecific crossbreeding has
resulted in hybrids having behavioral and growth
characteristics better suited for intensive culture than those
of purebred fishes. BUT NOT ALWAYS!
Examples:
Muskie x Northern Pike---Tiger Muskie
White Bass x Striped Bass--- Sunshine or Palmetto Bass
Plaice x European Flounder
Yellow Perch x Eurasian Perch
Natural hybridization between walleye and sauger
has been documented, and both reciprocal hybrids have
been artificially propagated in the laboratory.
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Hybrid walleye (Saugeye) have been stocked for
resource enhancement in as many as 11 states.
Limited impact?
Heterosis-Hybrid Vigor
Fertility
Overview• Growth studies over a decade ago established that walleye-
sauger hybrids grew as much as 2 times faster than the
purebreds.
• Organoleptic studies concluded that the hybrid walleye fillets
compared favorably with farm-raised purebreds, both of which
were preferred to wild-caught purebreds.
• Improvements in early spawning and fry feed-training
techniques provide the opportunity for out-of-season fingerling
production as well as eliminate the need for a pond phase of
production.
• Taken together these statements suggest that hybrid walleye
may be an ideal candidate for commercial RAS food fish
production.
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Question: Can we produce a food-size
hybrid from egg to plate in one year with
only indoor systems?
Objectives
• Use early season spawning and fry feed-training
techniques to produce hybrid walleye fingerlings in
indoor systems.
• Document key production characteristics for the
grow-out of hybrid walleye to food size in RAS.
• Provide farmers with food-size adult and feed-trained
hybrid fingerlings for market potential and field trials.
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Spawning and Feed-training• Early season spawning went as anticipated.
Two injections of hCG @500IU/kg 24 hours apart.
• Initially, brood stock sauger males were a challenge.
• Otohime diet, B1,B2, C1, 1.0mm Silver cup
• Fry training success was hard to quantify and highly variable.
• There was a learning curve.
• 85% survival from 4 inches to market size.
Materials and MethodsExperimental Tank Setup for Initial Rearing
•230 L round tanks
•Sidewalls painted black
•Gray bottom
•Adjustable lighting
•Flow
•24 hr feeders
•Surface spray
•Removable screens
•Daily cleaning system
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Surface
spray
Center screen
Directional
water flow
Otohime fry feed
200 -1400 m
Nelson Silvercup
walleye grower
1.0mm
Fry Feed
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20mm
60mm
Walleye/Saugeye Growth
0.0
100.0
200.0
300.0
400.0
4/23/09
5/7/09
5/21/09
6/4/09
6/18/09
7/2/09
7/16/09
7/30/09
8/13/09
8/27/09
9/10/09
9/24/09
10/8/09
10/22/09
11/5/09
11/19/09
12/3/09
12/17/09
12/31/09
1/14/10
1/28/10
2/11/10
2/25/10
3/11/10
Date
Saugeye
Walleye
Yellow perch
market size
Hybrid target
market size
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Weight Gain
0
50
100
150
200
250
300
350
4/20/12
5/20/12
6/19/12
7/19/12
8/18/12
9/17/12
10/17/12
11/16/12
12/16/12
1/15/13
2/14/13
3/16/13
4/15/13
Date
Saugeye
Walleye
Yellow perch
market size
Hybrid target
market size
1 year old Hybrid Walleye(1.0kg)
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Results• Brood stock injected in mid-April.
• Average fish size reached market target by December 1.
• Larger fish could be culled for sale by early November.
• Marketing could continue through the following March
• 50% yield for scaled skin-on fillets.
• Good market acceptance.
Challenges
• Availability of sauger brood stock
• Fry training learning curve
• Cannibalism
• Rearing density in RAS (55 kg/m3)
• Economics
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AcknowledgementsThis study is funded by State of Wisconsin support of the University of
Wisconsin Stevens Point Northern Aquaculture Demonstration Facility
and Wisconsin Department of Agriculture, Trade and Consumer
Protection Agricultural Development and Diversification Program grant
#’s 23001 and 25007. We also appreciate the assistance of the U.S.
Fish and Wildlife Service (Genoa, WI).