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

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60-70 F. The trough would be filled to a depth of 14 inches (i.e.,
1.2 feet). The water requirement to fill the trough to that depth was
calculated by multiplying the width X length X water depth (i.e., 1' X
4' X 1.2' = 4.8 ft'.
The space for holding fish would be 0.5 foot shorter because of the
screen and standpipe at the tail end of the trough. Therefore, the
holding space for fish would be 1' X 3.5' X 1.2' = 4.2 ft'. Since a
ft' of water contains 7.48 gallons of water, the holding space would
contain 30.6 gallons of water.
Capacity of Fiberglass Tank: 3' diameter X 2'_dee . A leak-proof
' standpipe is critical for the same reason given for troughs. The tank
would be filled to a depth of 16 inches (i.e., 1.3 feet) and contain
7.1 cubic feet or 53 gallons of water.
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Consideration: Rectangular troughs require less space than round
tanks so that more family lots could be reared within a given space
in a hatchery building. However, circular tanks have the advantage
of being self-cleaning that reduces labor requirements. In
addition, less flow is required in circular tanks to maintain the
same water quality.
Extrapolation of Feed and Water Requirements. Table 11 can be used to
a limited extent to determine facility needs for larger numbers of
fish or fish of different lengths. For example, if the number of
razorback suckers on October I were 5,000 instead of 500 as indicated
' in the table, the food and water requirements can be extrapolated by
moving all decimal points one place to the right with the exception of
total length and number of fish per pound. Therefore, five thousand
fish would weigh 98 pounds and require 3.1 pounds of food, a water
flow of 19 gpm, and a water volume of 56 cubic feet.
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If the number of fish were 50,000 3.5-inch razorback suckers instead
of 500, the decimal point would be moved two places to the right.
Therefore, fifty thousand fish would weigh 980 pounds and require 31
pounds of food, a water flow of 190 gpm, and a water volume of 560
cubic feet.
Table 11 can also be used to extrapolate feed and water requirements
on the basis of length. This is done with the assumption that the
metabolic rate of razorback suckers is inversely proportional to the
length per pound of fish until the fish reach sexual maturity when
growth is substantially less. For example, one thousand nine hundred
sixty (1,960) pounds of 7-inch razorback suckers would require the
same space, water flow, and feed as the 50,000 3.5-inch fish in the
preceding example related to the number of fish. The weight of the
50,000 fish was 980 pounds. If the fish are twice as long (7-inch) as
the previous example (3.5-inch), the weight would be double (1,960
pounds for 7-inch fish).
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