SALMONID^E. 79 



showed me some smolfcs similarly procured from the stomach of a marine fish. In 

 fact this has been constantly observed at different localities, proving conclusively 

 that the migratory smolt passes into the ocean. 



Smolts which descend seawards have been proved to return to the rivers as 

 grilse. In the Tweed in various years numbers of these smolts have been marked 

 by a silver wire having been passed through and fastened to the back part of their 

 tails. None were obtained the same year, but the experiment was continued 

 the succeeding season, and several were taken as grilse. The Duke of Roxburghe, 

 on May 14th, 1855, had a smolt marked by the insertion of a peculiar shaped wire 

 through its gills ; it was retaken July 21st, 1856, as a grilse, weighing 6^ lb. On 

 the other hand we are told that in May, 1855, 1300 smolts were marked at 

 Stormontfield by cutting off the adipose fin, and 22 were recaptured as grilse the 

 same summer, the first on July 7th, 1855, when it weighed 3 lb. Some excellent 

 observers are disinclined to believe that it is possible these fish can increase so 

 rapidly in size that a smolt descending in May a few ounces in weight, could be 

 capable of returning within two or three months as a grilse of some pounds, 

 but it is not impossible that as we see differences in the periods of descent 

 of the parr as smolt, so some smolts may return in one season, the remainder in 

 the succeeding year. It is very remarkable that grilse do not commence ascending 

 until two or three months subsequent to the descent of smolts, whereas had they 

 been upwards of a year in the sea it would appear strange why some few at least 

 had not put in an appearance, this invariable absence from the nets almost seeming 

 to point out the probability that they are not present. 



Some salmon appear to ascend almost any month of the year, but the grilse 

 come in large shoals, do not loiter about the mouths of rivers, and may be said to 

 be summer and autumn visitors. It has been advanced that grilse are not young 

 salmon, ignoring the fact that only in salmon rivers are there true grilse, and 

 where they exist there are also salmon. I have in the preceding pages shown 

 that they are transformations of parr, raised from eggs taken directly from salmon, 

 that they breed with salmon and that the young are indistinguishable from those 

 raised when both parents are the true Salmo salar. These grilse return to the sea 

 as grilse kelts, which reappear in our rivers as salmon. Mr. Toung states that he 

 has often marked grilse and that they have returned from the sea as salmon. 

 A grilse kelt of 2 lb. weight was marked on March 31st, 1858, and was recaptured 

 on August 2nd of the same year as a salmon of 8 lb. 



Respecting the rapidity of growth of salmon various experiments have been 

 instituted. In 1859 the Duke of Athol had three salmon captured, while 

 migrating seawards, weighing 10, 11^, and 12?j lb. respectively. These were 

 marked by a copper wire being placed round their tails, and six months 

 subsequently they were recaptured as they were returning to fresh water, and 

 their weight was ascertained to have augmented to 17, 18 and 19 lb. respectively. 



Having thus briefly detailed the life history of this fish from the egg to the 

 adult, it becomes necessary to revert to those forms which have completed 

 spawning. Those, commonly termed kelts, drop down from pool to pool in a very 

 exhausted condition, the males much more so than the females. They generally 

 remain in the river in a debilitated state, feeding upon whatever fish comes 

 in their way, not rejecting the young of their own species. At this period they 

 are readily captured, and very prone to attacks of disease, often dying in vast 

 numbers, while a heavy flood carries them off towards the sea, but they as 

 a rule continue some time in the brackish water of the tideway before seeking 

 the ocean. Although doubtless a few of these kelts mend in the rivers, recovering 

 their silvery lustre prior to reaching the sea, and others return at a future 

 period in a healthy state from the salt water, it seems questionable whether 

 too many are not now permitted to mend upon the salmon fry, thus reducing the 

 amount of stock in the river (see page 62). In olden times poachers, assisted by 

 otters, kept the number of kelts in check. 



During the winter season of 1881-82 the salmon disease seriously affected 

 the Tay and its tributaries killing vast numbers .of kelts, and by some people 

 a greatly diminished catch was prognosticated for the season of 1882. But the 



