RECENT RESEARCH UPON SALMON 237 



Archer. On several days in succession he asked the net- 

 fishermen to lay out their catch according to sex. They did so 

 without hesitation. Mr. Archer then obtained leave to make 

 a [small incision in each fish to expose the ovary, and proved 

 that the fishermen were just as often wrong as right. It is 

 probable, therefore, that all but the largest male kelts speedily 

 get rid of the cartilaginous growth on maxillary and mandible, 

 which distinguishes the male at the time of spawning. This 

 suggestion is considerably strengthened by some of the entries 

 in the tables of marked fish recaptured and recorded by the 

 Fishery Board for Scotland.* 



There are a number of instances such as the following : 

 No. 1,909 : An unspawned fish taken in the Spey on November 

 28th, 1896, is returned as a female weighing 18 Ib. The sex 

 at time of capture must have been evident beyond all doubt. 

 The same fish, recaptured on March 2yth, 1897, is returned 

 as a male kelt weighing 12^ Ib. Again, No. 2,032 is taken in 

 the Spey on December 23rd, 1896, marked and returned as a 

 male clean fish weighing j^ Ib. Recaptured on February i6th, 

 1897, it is returned as a female clean fish of the same weight. 

 In short, out of 190 fish specified in the return to have been 

 recaptured, no less than twenty-three, or about 12 per cent., 

 are shown as having changed sexes in the interval. This 

 surely ought to make one slow to found upon external 

 indications of sex. 



Reference has been made above to fresh light which has 

 been thrown upon the disputed question of the to-and-fro 

 migration of salmon between the sea and fresh water, other 

 than the single ascent to and descent from the spawning beds. 

 Obviously this point is of much importance to the preservation 

 of rivers and to any legislation which may be devised to 

 prevent undue depletion of stock ; because thereon depends 

 the amount of loss to which the stock is exposed during a 

 single season at the hands of net-fishers. Forty years ago the 

 * Report, Part II., 1902, pp. 63-72. 



