1884.] HYBRIDS AMONG THE SALMONIDjE. 29 



Lower pond, from 1875 parents. 



Length. Bars. Bars, 

 inches. 



No. 1 40 13 12 



No. 2 4-0 14 12 



No. 3 3-8 11 12 



No. 4 3-9 13 14 



No. 5 39 12 13 



Average.... 3'9 13| 12| 



These fish had the parr-bands somewhat more broken up than 

 those in the upper pond, while the bands varied from 11 to 14 ; they 

 were otherwise similarly coloured . 



If these averages are reliable, and I consider them to be so, among 

 the thousands of fish I saw in these two ponds, the increase or 

 difference or gain in length by selection of parents was nearly one 

 fourth of the total length of the fish at nine months of age, or in 

 those whose parents were hatched in 1875 over those whose parents 

 were hatched in 1876. As these larger-bred fish are likely to form 

 a larger race, a sufficiency will be retained for breeders; time, 

 however, can only show to what extent this will be realized. 



But although experience has shown that the eggs of the older fish 

 produce larger fry, and such as are better calculated to fight the 

 battle of life, the problem had to be solved up to what age can 

 breeding from Trout be continued with a reasonable prospect of 

 remuneration ; for it is clear that keeping sterile or scarcely prolific 

 fish would hardly be advantageous, while as soon as a diminution of 

 the vital powers "sets in, it is reasonable to suppose that the limit of 

 obtaining the finest offspring has been reached. Some of these 

 questions seem to have met with a most unexpected answer this year 

 at Howietoun, where the old fish have experienced a most extraordi- 

 nary mortality, not simply due to fungus 1 , but apparently consequent 

 upon age. First the males of these eight-year-old fish commenced 

 to succumb 2 , subsequently the females, many of which latter were egg- 



1 Fungus appears to attack most virulently old males and imspawned females, 

 but very rarely young fish. It would almost seem nature's mode of clearing off 

 kelts, which feed on the young fish, and are consequently injurious to salmon- 

 river's. This likewise accounts for the fact that in certain rivers where the 

 disease has been most virulent, the succeeding year's supply of Salmon has been 

 abundant. Possibly there will be less monsters in number, the remnants of last 

 year's kelts, but the amount of moderate-sized fish will more than compensate 



2 In a letter from New Zealand in the ' Field ' (Dec. 15th, 1883) it is observed :— 

 " In a great many of the creeks, after the fish get to 6 pounds weight, they 

 seem to fall off in condition and get long and thin, and grow greatly to head." 

 Now is this due to age or feeding ? If we take 8 years as about the age at 

 which Trout fall off, and deduct this from 1883, we come to 1875. The first 

 Salmo-fario ova which arrived in safety at Melbourne and Tasmania were in 

 1864, and we are told that " during the years 1873, 1874, 1875, and 1876, .... 

 33 850 Trout ova and fry have been distributed to suitable streams in Tasmania, 

 New Zealand, Victoria, New South Wales, and Western Australia " (Nichols, 

 • Acclimatization of the Salmonidse at the Antipodes,' 1882, p. 85). 



