113 



APPENDIX I. 



THE MARTKANAVE LAKE. 



With the object of examining Marikanave lake as a possible source of 

 fish, I recently visited the tank, -which will have an area at F.T.L. of above 

 30 square miles with a depth at the dam of 130 feet ; at its lowest the tank 

 can never fall below about hall the above area nor, except for silting, can 

 there ever be less than 60 feet at the dam since the sluices are placed at 

 that level above the bed ; the lake at F.T.L. will hold 1,100 million cubic 

 yards of water. This enormous body of water is Applied with vast quanti- 

 ties of fish food both from natural growths in the shallower areas which 

 from the configuration of the lake are extensive, as at Kodayar in Travan- 

 core and the Periyar lake and from its catchment area of 1,000 square 

 miles ; if stocked with productive classes of fish such as carp and properly 

 worked the lake would speedily become a very prolific and inexhaustible 

 source of food. 



The proper way to treat the lake would be for persons of knowledge 

 and capital to lease the fishery rights from Government for a long term of 

 years, to provide spawning and nursery ponds so as to stock the reservoir 

 annually with millions of the proper fry at an age when they can look after 

 themselves, and to employ power boats with trawls and other nets and also 

 large fixed or pound nets as in lake Biwa (Japan), to gather in the harvests 

 which would practically be continuous. Owing to its distance from populous 

 centres a large fresh fish trade would probably be difficult at present though 

 the railway is within a very few miles of its shallow parts and might make 

 special arrangements for a guaranteed supply ; but the fish could readily be 

 dried or otherwise preserved, and sent to the various markets, while the 

 offal, including heads and guts, would be useful as manure in the irrigated 

 (sugarcane) land under the tank. 



It has already been suggested that the warm Indian waters are far 

 more prolific of fish food and consequently of fish, especially carp, than the 

 cold European waters where, moreover, carp practically hibernate for half 

 the year ; in Europe a warm summer apprecially increases the carp harvest. 

 But even in European lakes where fish subsist solely on the natural food 

 supplied by a lake and its sources, 1^ cwt. per acre chiefly of carp (180 

 kilogrammes per hectare) is considered a medium annual yield, and if this 

 figure be adopted the annual produce of 20,000 acres would be 1,500 tons. 

 Taking another method of calculation ; in Europe a lake is considei-ed stocked 

 (with carp, etc.) if it holds fish at 1 lb. per 50 cubic yards ; assuming 

 throughout the year an average dej th available for fish life and food of only 

 30 feet or 10 yards, the lake of 20,000 acres at F.T.L. will provide about 

 960 million cubic yards ; allowing for the periodical shrinkage by irrigation 

 demands, etc., an average of only 600 million may be taken as available for 

 fish life I this volume would therefore safely nourish 12,000,000 lb. of fish 



