Within the writer's memory the main rivers of the West coast were fine clear streams. The waters provided irrigation for the rice fields and contained quantities of fine edible fish. These rivers are now thick turbid streams carrying a heavy burden of slime and silt.
We have probably one hundred different species of Carp alone, besides dozens of species of Catfish and many fine fish belonging to the families Osphromenidae, Notopteridae, etc., etc. Catfish can exist in slime and silt though it is questionable whether they can thrive, but Carp certainly require clear water to breed in.
One of our Carp the Kělah (Barbus sp.) has been described by Swettenham as the finest fresh water fish he ever ate in the East, and the Kalui (Osphromenus olfax) is so highly esteemed that several attempts have been made to introduce it into France, and it has been acclimatised in Mauritius, Australia and parts of India.
Tin mining is necessary and some pollution of the rivers is unavoidable, but there have been many cases where carelessly constructed dams have broken and a turbid flood of slime has been allowed to pour direct into the rivers for months while leisurely repairs are being made. Though much of the damage done in the past is irremediable, let us hope that a more general recognition of the value of the fresh water fisheries will result in a fair measure of protection in the future. There are still rivers which can be saved.
By saving our fresh water fisheries we shall save, incidentally, our rice-fields, for Rice and Fish in addition to being the two staple foods of the country are inseparable. When you destroy one you destroy the other.
Where you can grow rice you can catch fish and where you can no longer catch fish you cannot grow rice.
To explain: the mining silt which pours into the rivers gradually raises the bed of the stream and so causes a rise in the water table. A rise in the water table limits the area of drainable land, and drainage is as necessary to a rice field as irrigation. So the area which can be planted with rice becomes smaller and smaller until eventually the water table is so high that the river channel can no longer carry off storm water. The resultant floods deposit a layer of slime and silt on the rice fields and complete the work of destruction.
Fish cannot breed in the rivers polluted with slime and silt, so the Fisheries and rice fields perish simultaneously. In our policy of construction and development these facts should not be lost sight of.
There is yet another point which has received no attention and that concerns anadromous Marine fishes which enter rivers to spawn. Among these fishes the principal one is the Shad (Těru-
