TIIE ARTIFIOIAL PROPAGATION OF MARINE FISH
61
fitted with a plywood cover, treated on the underside with epoxy resin,
8nd painted on top. Access to the inner incubators was by hinged
plywood flaps covering 60 cm X 30 cm holes in the cover, immediately
&ope the tanks. These flaps had central slits covered with translucent polythene film for admitting light from overhead fluorescent
tubes. A slotted-angle steel framework supported all the unit components except the main reservoir, whioh stood on the floor, partly hidden
under the fibre-glass water bath.
AIR - LIFT
/DEVICE
I
1
1
1
w
100 cm
Scale 0
2 0
4 0
60
Fro. 13. Triple-tsnk plaioe-rearing unit : Port Erin, 1981. Side view.
(After Shelbourne, 1963b.)
The volume of diluted sea water made up each dey in the reservoir
Of a unit was considerably in excesa of the day's requirements. The
fouowing morning, the reservoir residue was measured with a dip-stick,
Q d the m o u n t of distilled water in the mixture calculated. Measured
volumes of hatchery sea water and distilled water were then added
to the residue, to provide the next 24 hours' supply.
In this way it was possible to maintain a oontinuoua flow of 888
w a k adjusted to 8 predetermined salinity below that of hatoherg
61
fitted with a plywood cover, treated on the underside with epoxy resin,
8nd painted on top. Access to the inner incubators was by hinged
plywood flaps covering 60 cm X 30 cm holes in the cover, immediately
&ope the tanks. These flaps had central slits covered with translucent polythene film for admitting light from overhead fluorescent
tubes. A slotted-angle steel framework supported all the unit components except the main reservoir, whioh stood on the floor, partly hidden
under the fibre-glass water bath.
AIR - LIFT
/DEVICE
I
1
1
1
w
100 cm
Scale 0
2 0
4 0
60
Fro. 13. Triple-tsnk plaioe-rearing unit : Port Erin, 1981. Side view.
(After Shelbourne, 1963b.)
The volume of diluted sea water made up each dey in the reservoir
Of a unit was considerably in excesa of the day's requirements. The
fouowing morning, the reservoir residue was measured with a dip-stick,
Q d the m o u n t of distilled water in the mixture calculated. Measured
volumes of hatchery sea water and distilled water were then added
to the residue, to provide the next 24 hours' supply.
In this way it was possible to maintain a oontinuoua flow of 888
w a k adjusted to 8 predetermined salinity below that of hatoherg