8123

• UCREFRP Catalog Number: 8123
• Author: Wydoski, R. S.
• Title: Coordinated Hatchery Facility Plan
• USFW Year: 1994.
• USFW - Doc Type: Need for Captive-Reared Endangered Fish and Propagation Facilities.
• Copyright Material: NO

The amount of food required for 100 pounds of 2-inch fish would '
be 5.6 pounds of food per day (100 X 5.6% = 5.6 pounds of food).
Similarly, the percent of body weight per day for 4-inch fish '
reared at 70 F (21 C) at a food conversion factor of 1.5 would
be: '
0.75 X 1.5 X 10 = 11.25 = 2.8 percent of body weight/day 1/
4 4
The amount of food required for 100 pounds of 4-inch fish would
be 2.8 pounds of food/day (100 X 2.81% = 2.8 pounds of food).
Therefore, 200 pounds of 4-inch fish can be reared on 5.6 pounds '
of food per day.
NOTE: As fish double in length (as an average per family lot),

the weight of food required per pound of fish is reduced by one- '
half (i.e., the metabolic rate per pound of fish is reduced by
one-half). Therefore, the food requirement per pound of fish is
inversely proportional to the length of that lot of fish.
1/ The projected growth of the endangered fish can be
extrapolated from Table 10 for other water temperatures. It

is advised that extrapolation be limited to persons with a '
thorough understanding of projections from this table
because of the complexity of interacting factors.
2. Applicability of Feeding Rate to Hatchery Operations. If the holding
capacity in weight for any length of fish has been experimentally
determined at a facility, then the holding capacity for fish of
differing lengths can be calculated by simply multiplying the pounds
per inch times the mean fish length. For example, 100 pounds of 2-
inch fish in the above example would translate into 50 pounds per

inch. Therefore, one can calculate the weight of 4-inch suckers by '
multiplying 50 pounds per inch times 4 inches to obtain a value of 200
pounds. Likewise, if the weight of a lot of 4-inch fish had been
determined experimentally, then the holding capacity would be 200 '
pounds divided by 4 inches = 50 pounds per inch. To calculate the
weight of 2-inch fish that can be held, simply multiply 50 pounds per
inch times 2 inches to obtain a value of 100 pounds.
NOTE: These calculations are only valid if all conditions (i.e.,
water flow, water temperature, dissolved oxygen, etc.) are the same.
3. Indoor Propagation Facility Needs for Razorback Suckers. The space
and water requirements for one lot of razorback suckers from a paired
mating are summarized in Table 11. This lot could be reared in '
rectangular troughs or circular tanks. The water requirements for
either container would be approximately the same.
Capacity of Fiberglass Trough: 1' wide X 1.5' deep X 4' long. It is '
important that the trough have a leak-proof standpipe for draining,
cleaning, and as a safety factor to prevent water loss from a power
failure. The water exchange would be low to fully use water heated to
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