414
N. BAIAKRISENAX NATR AND N. SARASWAHY
160C
571
11600
144
3696- 33c
g 88 - ; 30YI
TI)
L
X
8 0 - z 2772-’
6421 -
5 6 -
1540-
329 -
246 -
163 -
8 -
0 -
0
- Ripe female
*-------a Veliger larvae
Settlement
FIQ. 36. Curves illustrating the occurrence of veliger lmvm in plankton, settlement of
spat on test planks (histograms) and the condition of the gonad of adult females of
Badcia idea in respective months in Madras waters.
the various investigators using different methods without any uniformity in the exposure of panels, in their inspection, or in the identification of the species involved. It will be seen that in regions with
marked seasonal changes in temperature settlement of many species is
suppressed during the winter period. I n tropical conditions, seasonal
changes in temperature are relatively small and settlement continues
without interruption (Nair, 1957 ; Nagabhushanam, 1962). Even under
such conditions the extent of settlement varies from month to month.
In special habitats such as estuaries, tbe influence of salinity may prevent the uninterrupted breeding and settlement of some species (Nair,
N. BAIAKRISENAX NATR AND N. SARASWAHY
160C
571
11600
144
3696- 33c
g 88 - ; 30YI
TI)
L
X
8 0 - z 2772-’
6421 -
5 6 -
1540-
329 -
246 -
163 -
8 -
0 -
0
- Ripe female
*-------a Veliger larvae
Settlement
FIQ. 36. Curves illustrating the occurrence of veliger lmvm in plankton, settlement of
spat on test planks (histograms) and the condition of the gonad of adult females of
Badcia idea in respective months in Madras waters.
the various investigators using different methods without any uniformity in the exposure of panels, in their inspection, or in the identification of the species involved. It will be seen that in regions with
marked seasonal changes in temperature settlement of many species is
suppressed during the winter period. I n tropical conditions, seasonal
changes in temperature are relatively small and settlement continues
without interruption (Nair, 1957 ; Nagabhushanam, 1962). Even under
such conditions the extent of settlement varies from month to month.
In special habitats such as estuaries, tbe influence of salinity may prevent the uninterrupted breeding and settlement of some species (Nair,