50
J. E. SHELBOURNE
equal and s t e d y rate of 4 l./h into each of three standard glass inoubators below the delivery manifold. This arrangement provided a
constant head to facilitate delivery control. A short length of
" Perspex " tube was interposed into each tank feed pipe, enabling
the drip rate to be visually counted, checked and adjusted when
neoeseary.
Header
reservoir
Poly thene
header tank
Air pump
-FIG. 12. Triple-tank pleice-rearing unit : Port Erin, 1961. Front view.
Scale 0
20
40
60
80
IOOcm
(After Shelbourne, 1963b.)
The glass incubators below the header tank were fitted out in a
aimilar manner 'to those in the 1960 experiment at Port Erin. They
rat side by side in a black fibre-glass tank, through which hatchery
water was slowly circulated. This water bath buffered the incubatora
against the higher ambient temperature of the hatchery, but passed
on any temperature variation within the hatchery circulation. The
outlet pipes of the incubatora were extended through the front of the
water-bath to discharge into a waste gutter. The water-bath waa