WATERS AND HOLDING PROCEDURES
5
calculating desirable densities is an inch of fish per
gallon of water. Gordon (1950) calls attention to a
recent trend toward using a ratio between surface
area and inches of fish. The latter method does have
the value of emphasizing the importance of surface
area in the exchange of gases between the water and
atmosphere. However, in aerated tanks surface exchange might not be as important as volume. The
author is of the opinion that density should be specified in terms of grams of fish per hter of water, and,
where flushing is done, the rate of flushing should be
specified in terms of percent change of a tank's
volume in twenty-four hours.
In order to obtain a clearer understanding of these
various alterations of water by fishes we will classify
waters as to their biological states using the categories: new, aged, conditioned and polluted. Particular attention is called to the need for making a
distinction between aged and conditioned waters. It
will be noted that there is inadequate information on
conditioning of water and the polluting of water by
fishes. Nevertheless, we can profit by making use of
available information.
The Biological States of Water
New water is water that has not supported fish
life and is essentially free of other biota. There are
at least two possible sources of such water: spring or
well water and rain water collected in an earthen
pool. Aged or conditioned water (see below) or even
some types of polluted water may be boiled or otherwise treated to give it the characteristics of new
water.
Aged water we will define as that which has not
5
calculating desirable densities is an inch of fish per
gallon of water. Gordon (1950) calls attention to a
recent trend toward using a ratio between surface
area and inches of fish. The latter method does have
the value of emphasizing the importance of surface
area in the exchange of gases between the water and
atmosphere. However, in aerated tanks surface exchange might not be as important as volume. The
author is of the opinion that density should be specified in terms of grams of fish per hter of water, and,
where flushing is done, the rate of flushing should be
specified in terms of percent change of a tank's
volume in twenty-four hours.
In order to obtain a clearer understanding of these
various alterations of water by fishes we will classify
waters as to their biological states using the categories: new, aged, conditioned and polluted. Particular attention is called to the need for making a
distinction between aged and conditioned waters. It
will be noted that there is inadequate information on
conditioning of water and the polluting of water by
fishes. Nevertheless, we can profit by making use of
available information.
The Biological States of Water
New water is water that has not supported fish
life and is essentially free of other biota. There are
at least two possible sources of such water: spring or
well water and rain water collected in an earthen
pool. Aged or conditioned water (see below) or even
some types of polluted water may be boiled or otherwise treated to give it the characteristics of new
water.
Aged water we will define as that which has not