210 SALMO^'ID^ OF BRITAIN". 



e^<ys may give a good show as to numbers, but not in tlie size of the ova and 

 the subsequent condition of the young fry. To obtain the best results numerous 

 ponds must be under the sole control of one management, and means taken to 

 prevent their contents being tampered with, and in this way only can the breed of 

 trout be gradually improved. The argument may be advanced that young fish 

 reared in England are larger at one or two years old than are those raised in the 

 colder North, but such does not prove them to be more adapted for stocking pieces 

 of water. It is more probable that those raised in colder places have hardier 

 constitutions and are better able to fight the battle of life, while they certainly 

 grow much more rapidly when removed to a warmer spot than if left in Scotland, 

 and perhaps in a short time attain to a greater size than their relatives reared in 

 warmer southern streams will. 



Lochleven trout at Howietoun cease to be prolific breeders at eight or ten 

 years of age, and the late Mr. Arthur, writing from Otago (February 10th, 1885), 

 observed, " For what it is worth Ave find trout breeding every year. Certain lean 

 and moribund males, however, caught in 1875 and 1876, had no doubt ceased to 

 be fertile and these were seven to eight years old." 



I have seen trout in good condition near the end of the year in which no 

 seasonable augmentation in the size of the breeding organs had commenced and 

 they must necessarily have been sterile that season, but were in excellent condition 

 for the table.* On the other hand I have observed some badly-nourished forms 

 likewise sterile, and probably from this cause, while I have been unable to 

 discover any evident difference in the lengths of the fins of sterile and fertile fish 

 as observed by "Widegren.f 



Although trout generally migrate into the smaller contiguous brooks to breed, 

 large ones are more frequently found forming redds in the broader and deeper 

 streams than are smaller fish. But it is by no means rare to find large examples 

 having taken possession of pools in burns. 



A trout's redd or nest is a mound of gravel which would fill one or even two 

 wheelbarrows, and when by probably causing a shallow may assist in aerating the 

 water. The eggs themselves lie loose among the gravel at from one to two feet 

 below the surface. Eggs when shed are elastic, but soft, and sink in water ; 

 when artificially jDropagated, the milt of the male is added to the eggs as described 

 at page 31 aiite. The period for which milt will remain serviceable after removal 

 from the fish is an interesting subject. On October 23rd, 1874, some was 

 obtained at Howietoun at 9 A.m. from a Salmo fario, then carried to Loch Leven in 

 a tightly corked phial, and used at 1.20 p.m. : the impregnation turned out to be 

 perfect. Ova or milt may be kept alive for some hours, but the addition of 

 water is rapidly fatal. 



April 8tli, 1887, at Delaford Fish Farm, I observed a very considerable diifer- 

 ence in the colours of the alevins, the sac of those from the Colne trout eggs were 

 red, whereas others from elsewhere were more or less straw-coloured or pale. The 

 adipose dorsal fin of Kennett trout showed very slight orange, so also did both edges 

 of the caudal, while there was none on the adipose fin of the Lochlevens. Two days 

 previously I had visited Mr. Andrews' famous establishment at Guildford, where 

 in some yearling Lochleven trout raised from Howietoun eggs I found as follows: 

 — 8, 8, 9, 9, 9, 10, 10, 11, 13, 13, par bands. In all the adipose dorsal was tipped 

 with orange and caudal red margined. Also the alevins showed orange on the 

 adipose dorsal not only as soon as the sac was absorbed, but even previously. I 

 also examined a number of brook trout from the local race and found 9 to 10 

 bands normal, but one had 15. They had the orange on the adipose dorsal fin 

 very unequally distributed, and one had three beautiful vermilion spots on it. A 



* Taylor in Angling in all its Brandies, 1800, observed that in the Clun, Shropshire, there are 

 a number of trout which do not grow very large : but the angler will often take barren trouts, that 

 are excellent in winter, when other trouts are good for nothing. See also F. Gosden, Fishing 

 Gazette, 1886, p. 28. 



t Widegren observed that in Scandinavia sterile trout were more silvery than specimens of 

 the same age and size which had ova and milt developed. 



