191
calculating basal metabolic rate:
Where M
Results
www
log M = log 74.3 + 0.744 log W±0.074
heat production in kcal day−1
W = body weight in kg.
a) Environmental Conditions and Primary Productivity
Values for environmental parameters and primary productivity (phytoplankton and simple periphyton), measured in terms of chlorophyll, are given in Table 1. Although minimum air temperature reached 5.5° in January 1979, the lowest recorded water temperature was 14.6°. In April 1978 the salinity of the water was about 50% of that of sea water (30%), but fell to a low level during the wet season. The highest values were recorded during the last four months, due probably to a combination of low rainfall and the entry of comparatively large amounts of sea water. The pH approximated to that of seawater (8.0-8.3) for much of the period but became slightly acidic in late July, August and September. Dissolved oxygen in the surface water was high throughout the experimental period and should always have been sufficient for all but the most demanding animals. Moreover, at the comparatively low salinity, the nitrate content might well have been quite high (Fogg, 1980).
In comparison with the water of Hau Hoi Wan as measured off Tsim Bei Tsui by Vrijmoed (1975), pH and dissolved oxygen were slightly higher in the kei wai, but salinity was about the same level and showed a similar seasonal fluctuation.
The most obvious element of primary production was the red alga Ceramium sp., of which 14,000-17,500 kg. (mean: 15,750 kg.) is harvested per annum. Growth is particularly prolific between the first and fifth lunar months and it is certain that some part of the total production of Ceramium would be consumed by herbivores.
191
calculating basal metabolic rate:
Where M
Results
www
log M = log 74.3 + 0.744 log W±0.074
heat production in kcal day ́1
W = body weight in kg.
a) Environmental Conditions and Primary Productivity
Values for environmental parameters and primary productivi- ty (phytoplankton and simple periphyton), measured in terms of chlorophyll, are given in Table 1. Although minimum air tem- perature reached 5.5° in January 1979, the lowest recorded water temperature was 14,6°. In April 1978 the salinity of the water was about 50% of that of sea water (30%), but fell to a low level during the wet season. The highest values were recorded during the last four months, due probably to a combination of low rainfall and the entry of comparatively large amounts of sea water. The pH approximated to that of seawater (8.0-8.3) for much of the period but become slightly acidic in late July, August and September. Dissolved oxygen in the surface water was high throughout the experimental period and should always have been sufficient for all but the most demanding animals. Moreover, at the comparatively low salinity, the nitrate content might well have been quite high (Fogg, 1980).
In comparison with the water of Hau Hoi Wan as measured off Tsim Bei Tsui by Vrijmoed (1975), pH and dissolved oxygen were slightly higher in the kei wai, but salinity was about the same level and showed a similar seasonal fluctuation.
The most obvious element of primary production was the red alga Ceramium sp., of which 14,000-17,500 kg. (mean: 15,750 kg.) is harvested per annum. Growth is particularly prolific between the first and fifth lunar months and it is certain that some part of the total production of Ceramium would be consumed by herbi-
vores.
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