i6o THE SEA-TROUT 



■' bagged " in outline, is black but uncomely, for her scales have 

 darkened and all her gleaming white underparts have become dark. 

 In any ordinarily flowing stream the red male fish is a conspicuous 

 object at spawning time, but I have found it generally less easy to pick 

 out the dark grey female in the current. I am able to give here (Fig. 

 51) a reproduction of a very perfect photograph, taken by Mr. Hutton, 

 of the head of a 30 lb. Wye salmon which I caught at Hampton Bishop 

 on August 14, 1915, the fish from which diagram Fig. 13 (i) was drawn. 

 The projection of the lower jaw is admirably shown in the photograph, 

 and I think the spawning livery of the male fish is as clearly indicated 

 as it can possibly be indicated without the assistance of colour. I also 

 show (Fig. 52) a male and female salmon on the eve of the spawning 

 season. With the male fish may be contrasted the male sea-trout which 

 I show (Fig. 53). 



There is no doubt I think that some of the sea-trout which ascend 

 from the estuary each season are barren fish and will not spawn. On 

 September 29, 19 15, I caught one with fly in Loch Lomond, weighing 

 I J lb., of such a silvery brightness that, concluding it to be fresh run, 

 I looked to see if it had any sea-lice or traces of them on it, but none 

 was found. Subsequent autopsy proved it to be a male fish with the 

 testes wholly undeveloped. The measurements of length, 15! ins., 

 and girth, 8 ins., proved it to be in the pink of condition. It could not 

 have already spawned, therefore, and could hardly have spawned later. 

 The questions arise, first, whether the silveriness of its scales was due 

 to the fact of its barrenness, and, secondly, whether this is so far proof 

 that the change of colour of fish at spawning time is directly attributable 

 to the exercise of the spawning function. Examination of the scales 

 showed that the fish was not a whitling but a sea-trout, because the scale 

 growth indicated that a period of nearly two years had elapsed since 

 the descent of this fish to salt water as a smolt. 



The process of spawning has often been described in the case of 



