South Paw
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« Reply #2 on: May 20, 2010, 08:27:45 AM » |
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Everything went smooth yesterday with the fish. We received 100,000 Chinook (99,985 by Burt's count). This is historically later than we normally get the fish. So rather than keeping them in the pens for 4-5 weeks we will only be caring for them for 10 days or so. Below I'll paste the explanation that George Madison e-mailed me (I think it's already been posted here) explaining the late arrival. Another factor we talked about yesterday was with the state budget cuts and very limited overtime it is taking longer to do all the plants throughout the spring. What used to take 4 days now takes 8.
How will this affect the success of our project? This is up for debate. I'm sure there are plenty of you with your $.02. We do know that it stresses the fish considerably when they are transported from the hatchery. Having them placed in the pens rather than dumped off a bridge gives them time to readjust in a safe environment rather than being subject to all types of predators. SSFA also releases the fish from the pens under the cover of darkness to help lessen aerial predation. Will 10 days be enough for the fish to imprint to the river. We hope so.
From George
Colleagues,
The Lake Superior Chinook salmon net pens will be stocked during the
period of May 17, 18, 19. Fish food and a feeding schedule will be
brought to your site when the fish are delivered. Your fish will arrive
at the same approximate time of day as you have received fish in the
past years. If you provide me with a phone contact, I can call you on
the day of the plant to let you know the more specific timing of the
hatchery truck to your site. The fish are arriving later in the month
of May this year than they have in past years. The reason for this
change in plant-out timing is detailed below.
The long range weather forecast is predicting 60-70 degree temperatures
for the week of May 24-28, and with the low water levels in the
receiving rivers these Chinook will need to be released from the pen
nets no later than Saturday May 29th.
If you need to contact the DNRE at any time during the pen rearing
period, you can reach Hatchery Biologist Jim Aho at the Marquette State
Fish Hatchery at 906-249-1611 ext 324, or Hatchery Biologist Randy
Espinoza at the Thompson State Fish Hatchery at 906-341-5581 ext 201.
If any issue or emergency arises, please contact me, George Madison,
immediately 24/7 at 906-280-1045.
Planting Schedule
Monday, Black River Harbor - Net Pen 25,000
into one net pen + 50,000 direct to the river
17th
Tuesday, Big Iron Silver City - Net Pen 25,000 into one
net pen + 50,000 direct to the river
18th
Wednesday, Dead River - Net Pen 100,000 distributed
into 4 net pens @ 25,000 for each pen
19th
Thursday Carp River, Marquette
100,000 direct plant to the river
20th
Why are the Lake Superior Chinook salmon being planted late this year?
Historically, the Michigan DNRE Thompson State Fish Hatchery stocked
Lake Superior Chinook net pens early during the month of May; however
changes in the hatchery fish food will mean that the 2010 plant and
future stockings will occur in mid to late May.
The DNRE State Hatcheries have been feeding all Chinook salmon with an
Oxytetracycline (OTC) impregnated fish food in order to imprint an OTC
fluorescent mark on the skeletal bones of these fish. This OTC marking
provides for a means of identifying and determining what lake-inhabiting
Chinook are actually products of hatchery reared fish or products of
wild naturally produced fish. The OTC marking system is one of the
fundamental tools used for determining the contribution of stocked fish
to the sport fishery. Fish stocking evaluations are necessary for
biologists and anglers to understand the overall benefit that is
realized as compared to the cost of rearing trout and salmon. In order
to for the OTC chemical to successfully imprint onto the bone structure
of the young Chinook, these fish have to be a minimum size (about 2.5
inches) in order for the mark to adequately infuse into the bone
structure of the fish.
Due to increased worldwide aquaculture demands for fish food, feed
costs have risen dramatically and are continuing to increase at a rate
of almost 10% per year. This escalation in fish food costs, combined
with the likelihood of steeply expanding costs in the future, is putting
a significant strain on Fisheries Division’s budget for trout and
salmon rearing programs. DNRE Fisheries Division has recently begun
experimenting with a fish diet that is less expensive than the
traditional supply of feed. Hatchery managers can utilize this lower
cost feed supply and still produce a high quality fish for stocking.
The downside of this new fish diet is that the fish grow slightly slower
which delays the ability to OTC mark them by about two weeks. This
slower growth rate in-turn delays stocking by about two weeks.
The new type of fish food used for salmon rearing will cost about
one-half of the traditional feed expenditure, which will result in a
significant cost savings to the Hatchery budget. Overall, the State can
realize a considerable level of cost savings by using this new feed,
while still producing a high quality stocking product. The bottom line
is that the DNRE has no alternative but to continue to find ways to
produce good fish at a lower cost. Due to these constraints it is very
likely that all future Lake Superior Chinook stocking will occur on a
mid to late May time line.
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