SMOLTS READY FOE SEA. 197 



spots are visible. It is now ready at the first 

 fitting opportunity to commence journeying down 

 river to the sea. In order to induce and enable 

 smolts to do so, it is not necessary that rivers 

 should be flooded, but there must be a sufficient 

 volume of water to carry the migrating fish safely 

 over weirs, shallows, and other impediments. 

 They will not migrate at low water. They gene- 

 rally do so from their native rivers to the sea — tide 

 and time permitting — from the 15th April to the 

 middle of May. At that epoch rivers are gene- 

 rally full, neither flooded nor the reverse. Often- 

 times their migration takes place earlier, and fre- 

 quently later in the year. Late migration is 

 caused by late spawning, which is the result of a 

 late "close" time, or not allowing salmon to ascend 

 the rivers freely in the early autumn months — in 

 other words, killing the early spawners by means 

 of nets, cruives, and other devices after the month 

 of August has expired. 



The reader must have already remarked the 

 very slow growth of salmon-fry. At the end of a 

 year, the whole of it passed in fresh water, the 

 young fish, on an average, weighs little more 

 than four ounces. At that weight, being a smolt, 

 it descends to the sea; and, if it should remain 

 therein, say for eight or nine weeks, and then 



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