THE BEHAVIOUR AND PHYSIOLOGY OF HERRING AND OTHER CLUPEIDS 285
the body fluids first showed a rapid change in concentration. Regulation
started within 6-12 hr and the body fluids were returned to close to
their original value. I n salinities above 12%,, (the isotonic point) the
body fluids stabilized at a value roughly one-third of the external
salinity. Below la%, the values were only slightly lower than the sea
water values. The larvae showed changes in body weight corresponding
Control in
sea water
0.30 5
__-_
L
I
.
I
1
- 1
20
40
60
0 I Slllnlry ( /,,)
Fro. 2. O~niotir c-oticentrations of larval body flIlidH. larvcu, trnurrforrd f r o m no8 wator
(32.3%,). (Reproduced with permission from Holliday and BIaxter, 1960.)
to a loss of water in the high salinities and a gain of water in the low
salinities, the weight returning to near normal after successful regulation.
Within the salinity range 2.5-52.5%,, the larval tissues were regulsbd
to equivalent salinities 9.8-15.0%, (A = 0-59-0-90). Before regulation
was complete, however, the larval tissues experienced and survived
internal concentrations equivalent to 8.7-27-5% (A = 0.52-1.06) ;
in normal sea water the value waq equivalent to 12%,, ld --- 0.72),
see Fig. 2. Lasker and Theilackcr ( I ! j O h ) oht,sinrxl rr:niJltn o r 1 ,Yw.
dinops caerulen larva(. showing that irr sw, wati.r of :iGX,, mlqj ti'%,., t,hr: