7026

• UCREFRP Catalog Number: 7026
• Author: Deacon, J. E. and W. L. Minckley
• Title: Desert Fishes
• USFW Year: 1974
• USFW - Doc Type: Desert Biology
• Copyright Material: YES

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424

JAMES E. DEACON AND W, L MINCJ(LEY

Baume units (American stand.) LiquidS heavier than water
Cl
o 2 3 4 5 6 7 8 9 /0 " 12 13 14

160 14 16 18 20
260

140

20

~ 120
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j 100
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'U
~ 80
'U
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~ 60
'6
'6
i2 40

o
0.990 1.000 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.100 1.110

Specific gravity (Density)

Fig, $, Relationships of measurements of total solids in water at different environ-
mental temperatures. Note that this is intended only as a generalized figure, since
various ionic compositions create different densities (Agnihotri and Tewari. 1968),
etc. Data on densities and total dissolved solids were extracted and/or extrapolated
from information provided by Schureman (I 941 ), and for Baume units from the
Merck Index (Strecher, 1968).

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almost-lethal osmotic stress. For example, Cyprinodon ( = Aphanius) dis-
par was taken from a brine pool near Kabret, northeastern Africa, which
had densities of 1.176 throughout most of the pool, but 1.040 near the mar-
gins (Fox, 1926). The fish were most abundant near the edges where fila-
mentous algae grew, but a few were in areas of maximum concentrations
of dissolved solids. All ions except calcium increased with increasing den-
sity. The similarly vast chemical (and thermal) differences in stratified
pools of Cuatro Cienegas basin (Cole and Minckley, 1968) have already
been discussed (Section III,A,S). Association of fishes with aquatic
' plants such as filamentous algae (Fox, 1926) or Chara in saline ponds
may indicate slight chemical changes in the vicinity of the plants due to
photosynthetic activities, but this has not been specifically studied. The
plants may of course also be surviving only in the least toxic part of such
a pool.
In general, fishes of diverse groups have demonstrated the capability of
persisting in salinities up to 2 or 3 times the concentration of sea water

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