of the Fishery Board for Scotland. 



61 



APPENDIX V. 



NOTE ON CROSSING OF SALMON STOCK BY TRANSPORTING 



RIPE MILT. 



By W L. Calderwood. 



The custom of transporting fertilised salmon eggs from one river to 

 another has now become very familiar, and by this means many attempts have 

 been made to introduce entirely new stock to rivers. An experiment, which 

 is an alternative of this, was made during last winter (1909-1910) and is 

 worthy of note. This consisted in transporting ripe milt from two rivers 

 in Scotland to the Cheshire Dee, It not infrequently happens that, 

 when ova-fishing for hatchery purposes, ripe males are not as plentiful as 

 ripe females, and I have known of men putting the ripe milt in a bottle 

 and carrying it about with them during the day. So far as I am aware, 

 however, no attempt to transport milt from one river to another has been 

 carried out, or, if carried out, has been made public. For purposes of 

 crossing fish stock, it now appears to be possible to send or carry ripe 

 milt from one district to another. 



Ma.-jor Leadbetter, of the Dee Board of Conservators, Cheshire, who 

 instituted these experiments, has kindly given me the particulars. 



The first trial was rather severe, the milt being carried all the way from 

 Conon, in Ross-shire, to the Welsh Dee. Arrangements having been made 

 with the Conon district authorities, that river was netted on 8th 

 December, and of 13 males caught, 9 were placed in a floating cage for 

 future use. Similarly two female salmon ready for spawning were 

 secured and kept in a sort of cage in the Dee, before the Superintendent 

 started for the Ross-shire river. He arrived there on the morning 

 of 21st December, and a quantity of ripe milt was secured without 

 delay from the Conon fish. This was placed in bottles and carefully sealed, 

 and the bottles were then packed in moss to minimise shaking. By 1.15 

 p.m. the return journey was commenced, Chester being reached on the 

 morning of 23rd December. By 10 o'clock on that date 22,000 eggs were 

 fertilised and laid down in the Dee Hatchery, The actual time taken on 

 the journey was 21 hours. 



In the case of the other experiments, the attempt was made to transmit 

 the milt by post from the Tweed. Although the time necessary for the 

 journey is only 10 hours, very considerable delay occurred owing to the 

 New Year holidays intervening. Three attempts were made, the first 

 taking 18 hours, the second 40 hours, and the third no less than 63J 

 hours. These Tweed experiments appear to have been unsuccessful, but it 

 is thought that the shaking which the milt received when in the hands of 

 the parcels post authorities may in some measure have accounted for the 

 loss. In any case, the result is that the length of time during which milt 

 will remain fertile when carried in this way has not been determined. 

 Fertilisation appeared to have taken place to some extent even in the case 

 of the 63 hours' experiment, but subsequent results have shown these 

 trials to be failures. In transporting pheasant eggs for rearing purposes 



