92 



these fluctuations would be an extremely difficult and unsatisfac- 

 tory task ; it would also be one of doubtful utility both on 

 account of the many lacuna? in the information available and 

 because of the complete lack of correlated and contemporaneous 

 records of those biological and hydrographic conditions which 

 we presume to be intimately concerned in influencing the 

 periodical movements of migratory fishes. To arrive at a 

 serviceable explanation of the problem we shall have to obtain 

 intimate knowledge and keep systematic record of the relative 

 seasonal abundance of plankton both in bulk and in detailed 

 constitution within the areas under investigation, of the weather 

 conditions prevailing at the same periods and places, the 

 clearness or the turbidity of the sea at the times when shoals 

 are numerous and of the direction of the inshore drift at the 

 critical periods ; particular attention must also be paid to ascer- 

 taining with exactitude the proportion in which different 

 organisms contribute to the food of sardines and mackerel 

 respectively so that this may be compared with the constitution 

 of plankton collected simultaneously. 



The conduct and results of such investigations will be 

 particularly important and illuminative in seasons when sardines 

 or mackerel appear to desert inshore waters. In such a year 

 besides the scientific investigation and record of biological and 

 hydrographic conditions, exploration of the deeper zones outside 

 the ten -fathom line in search of the missing shoals should be 

 prosecuted with unremitting energy in view of the great eco- 

 nomic importance of a solution of this question, to say nothing 

 of its intrinsic scientific interest. 



59. The vast importance of the sardine and the mackerel to 

 the fishing population of Malabar and South Canara as well as 

 to the coast populations of Granjdm, Vizagapatam and Tinnevelly 

 districts on the East Coast cannot easily be overestimated, in 

 as much that they have sometimes been dubbed kudumlam pular- 

 thi, " the provider for the family ". The great industrial value 

 of the two fisheries in question may be gauged in some degree 

 from the figures of the quantities treated in fish-curing yards 

 during the period 1896- 1908 shown in the table which follows 

 this paragraph. It must also be borne in mind that an additional 

 quantity, which probably approximates to at least one-half of 

 the average of these years goes into consumption in the fresh 

 condition, and that a relatively enormous surplus is turned into 

 manure after the food market is fully satisfied in those years 

 when sardines are exceptionally abundant as for example 

 1906-1907 and 1907-1908 when quantities approximating to 

 12,000 tons and 34,000 tons respectively were exported from 



