Aquatic ecosystem of park lake is healthy
I REFER to your correspondent, John Leigh's complaint about the waterfowl lake at Hong Kong Park (South China Morning Post, October 19).
The water quality of the lake is maintained in a state compatible to the habitat of the birds kept there. To this effect, the water is circulated through a sophisticated filtration system and is changed at regular intervals.
Water tests are carried out frequently to ensure good quality. The ''fifthy'' appearance is due to the coloured concrete lining on the bottom of the lake provided to simulate an eroded bank.
The ''water ducks'' to which your correspondent refers are in fact Whistling Ducks (Dendrocygna), Shelduck (Tadorna) and Wood Duck (Cairina). In nature these birds spend more time out of the water than in it. The same applies to pelicans, darters and cormorants. In short, the birds are behaving in a completely normal manner.
Mosquito larvae however cannot exist in the lake, because they are consumed by the large number of fish kept there. The very fact that there are dragonflies and chironimids present is an indication that the aquatic ecosystem is healthy.
Wild Common Kingfishers (Alcedo atthis) frequently come to fish in the lake, which they certainly would not do if the water quality was bad.
Your correspondent may rest assured that we do care as much as he does about the waterfowl kept in our park.
T. K. LAM Regional Leisure Manager (Hong Kong West) for Director of Urban Services