This is from Jim Held a respected researcher in aquaculture. I received this via a yellow perch list serve I am on. I don't completely agree with his comments on yellow perch but he does knows more about aquaculture than I will ever know.
Folks,
It's been a while since we've considered the potential of walleye and
hybrid walleye (sauger x walleye) for commercial culture. Many of you
receiving this e-mail were involved in the NCRAC and SeaGrant studies
back in the 90's, so I thought I would update you on some recent
work. In a small study over the past year, the Northern Aquaculture
Demonstration Facility has come up with what we think are some fairly
spectacular results. We combined early out-of-season spawning with
intensive fry rearing (Bob Summerfelt's method) and both pond culture
and RAS of the trained fingerlings to produce extended growth
walleyes (for stocking) and food-size hybrids (for consumption).
More and more resource agencies and lake associations are requesting
extended growth (8"+) fingerling walleyes for stocking. The high cost
of small (grade 10) forage makes this a very expensive proposition.
Training the fry and maintaining them in culture until they can take
larger, less expensive forage is a big step in reducing production
costs. We also had some success at keeping the fish on formulated
feed during grow-out in the ponds. Alternatively growing the pure
bred walleyes up to the 8"+ size in RAS could provide the high value
product that makes recycle economically feasible. An added benefit of
the intensive culture protocol is protecting the fingerlings from
diseases like VHS and eye fluke that has impacted production of
extended growth walleye fingerlings here at the Lake Mills State Fish
Hatchery.
RAS culturists have always wanted a food fish that they could
"finish" in 1 year completely indoors. It seem clear to me that
yellow perch just don't fit the bill. The current intensive fry
culture techniques (green water, artemia) are expensive and
inefficient. Additionally, because of the slow growth of the very
small fingerlings the perch just don't make it to market size within
the year. Early spawning of the walleye and hybrids gave us an extra
six weeks of culture time, and most importantly the fry culture
didn't involve the use of any live feed. Even in our first attempts,
with the advice of Alan Johnson, we were quite successful in getting
the newly hatched walleye to take feed and survive. RAS culture of
the hybrids resulted in fish that averaged 160g and 10.5" by Nov. 1st
with fillet yields in the 50% range and fillets that weighed 80g per
fish (similar to large market size perch at 3/lb). Growth rates at
the end of the study averaged 1g/day with some fish in the cohort
growing faster than 2g/day, so one could have 250g hybrids by
February. The fillets from those fish would be 125g the same as
filleting a 265g perch! Keep in mind that that these fish are less
than 1 year old!!!
Several commercial producers here in Wisconsin have expressed
considerable interest in the walleye project. They thought the "baby
walleye fillets" were very tasty and were able to market the fish we
produced. Of course this was only a pilot study and there are still
questions to be answered concerning broodstock, culture density and
economics among others. The bottom line is these walleye and hybrid
techniques can benefit both public and private sector producers in
the North Central region and provide a new direction for RAS operators.
I think that it would be great if this idea got some serious
discussion and consideration prior to and at the upcoming NCRAC
meeting. I hope that you pass this message on to any producers in
your state that may be interested.
Regards.
Jim Held
Aquaculture Outreach Specialist
UW-Extension
jaheld@wisc.edu
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