WHITLING 135 



of course assumption is not proof, why the shoals should get broken up 

 whether in migrating upstream, or migrating down stream, or roving in 

 the estuary. Whether the two wings of the shoal ever re-unite or not, 

 there can be no question that they are again ranging about contem- 

 poraneously feeding in the estuary or the sea. 



The young sea-trout now find a rich harvest, for they are big enough 

 and swift enough in their movements to prey upon fish of considerable 

 size. Besides small shell-fish and sand-hoppers and other small deer, 

 shrimps and sand-eels form a large part of their dietary. But without 

 question their staple food in the early summer months is herring fry. 

 In May and June enormous quantities of these little fish — they are 

 about three inches long — approach the shores and myriads of them 

 enter our sea-lochs and push up the estuaries as high as the tide will 

 carry them. Sea-trout then feed upon them voraciously, and I am 

 inclined to the beHef that, when the sea-trout which enter fresh water 

 are observed to be of poor quality in any season, the explanation is that 

 there has been a deficiency of herring fry in the shore waters during 

 that year. The numbers of these fry that a sea-trout will consume in 

 a day must be very great. I have found in one fish of about a pound 

 weight as many as eleven not wholly digested, besides a mass of scales 

 and bones in the anal canal. It looked as if this sea-trout, while 

 feeding, could, and did, swallow and digest fresh supplies as rapidly 

 as it could pass the unassimilated matter through its body. 



There is good reason, beyond the mere growth of the fish, for this 

 extreme voracity, because the sea-trout has now to lay up within its 

 tissues a reserve of energy-making fat sufficient to meet not only the 

 exhausting journey to the upper waters, but the more exhaustive process 

 of the development of the milt and ova. There is at least no question 

 that if the sea-trout ascend to fresh water in this, the second summer 

 since they descended as smolts, they will proceed to spawn before 

 returning to the sea again for they have now reached maturity. 



