178 SALMONIDiE OF BRITAIN. 



the following instances from the Tweed experiments eliminated doubtful cases 

 and restricted my examples to such as Lave been considered in all stages to have 

 retained their sea- trout characteristics. Among those taken in or near the Tweed,* 

 and if these experiments were not erroneous, we find that a smolt or orange fin If oz. 

 in April, 1873, may be a 1| lb. whitling in June, 1874, or a smolt may become 

 a 3 lb. Bull trout in twelve months : or in three years weigh 5 lb. While 

 although a Black-tail was observed to increase from 8 oz. to Ih lb. in seventeen 

 months, another from 9 oz. to 1 lb. 3 oz. in nine months, and a third from 13 oz. 

 to 4| lb. in twenty-eight months, on the other hand one example 11^ oz. in weight 

 had actually decreased to 10 oz. in six months, and a second from lOi oz. to 5 oz. 

 in the same time. Among the whitling likewise, one 17 inches long and 

 weighing If lb. increased in twenty-three months to 18f inches long, and weighed 

 2^ lb., while a Black-tail 12 inches long and 12 oz. in weight increased in nine 

 months to 13 inches in length and 17 oz. in weight. The foregoing show 

 how very variable both the rapidity of growth as well as the augmentation in 

 weight may be. 



Passing on to instances from the same river wherein the marked fish have 

 been captured in distant localities, we find from the observations of the Tweed 

 Commissioners, t that these fish migrate long distances, as one from the Tweed to 

 Yarmouth, in the space of a few days over a month, and during that period it 

 increased ^ lb. in weight. But the same variations in increase both in length and 

 weight are shown in fishes thus migrating long distances, just as in those which 

 appear to remain nearer to their native river. 



Tlie food consumed by the sea trout is very similar to that of the salmon, but 

 in some respects they seem to be more voracious. 



I removed from the maw of a small example (14 in. long) from the Aberdeen- 

 shire Dee, taken in July, 1882, four sand launces, Ammodytes.X Sir W. Jardinc 

 found its common food to be the sand hojiper, Talitrus locusta. Phinocs in rivers 

 are partial to the fresh-water shrimp Gammarus pulex. Tliat they will 

 consume fish eggs is well known, thus Bertram (p. 191>) recorded how a whitling 

 in 1882 of about f lb. weight had been taken in the Tay with 300 salmonoid eggs 

 in its stomach. 



Mr. Jamieson, Fishing, December 18th, 1886, gave an account of some 

 investigations he had made respecting the food of sea trout in the Nether Don 

 and a little above it, extending fi-om the Cathedral of St. Machar to where the 

 river discharges itself into the sea. 



" The greater portion of this is tidal water, and, consequently many of tlie 

 stomach-contents of these trout were derived from the sea. During the months 



* Orange fin or trout smolt marked April or May, 1851, became a clean Bull trout 51b. weight, 

 May, 1854 : Smolt, Mav, 1857, a Bull trout, 3 lb.. May, 1858 : Black-tail, October, 1859, a Whitling, 

 U to 2 lb., March, 18(51': Whitling, If lb., September, 1870, a WliitHng, 2i lb., July, 1872 : Bull trout, 

 21 lb., Sept. 20th, 1870, to a Bull trout, 5^ lb., August, 1871 : Black-tail, 12 oz., October, 1870, to a 

 Whithng, 17 oz., June, 1871: Black-tail, 21 oz., October, 1871, a Whithng, 2' lb., August, 1872 : 

 Orange fin. If oz., April. 1873, a Whithng, 1 lb. 8 oz., June, 1871: Black-tail, 9 oz., Sept., 1873, a 

 Whithng, 1 lb. 3 oz., June, 1874: Black-tail, 14.i oz., Nov., 1877, a Buh trout, 28 oz., August, 1879 : 

 Black-tail, 13 oz., Nov., 1877, a Bull trout, 4.V lb.. May, 1879 : Black-tail, 11 oz., Nov., 1875, a 

 Bull trout, 3 lb. 12 oz., August, 1877: Black-tail, llj oz., Nov., 1877, a Black-tail, 10 oz., April, 

 1878 : Black-tail, 11 oz., Nov., 1877, a Bull trout, 2| lb., August, 1879 : a Black-tail, lOi oz., Nov., 

 1875, a Black-tail, 8\ oz., March, 187G : Black-tail, llj oz., Nov., 1877, a Black-tail, 10 oz., April, 1878. 



•j- Bull trout kelt, 3 lb., March, 1852, recaptured at Yarmouth, April, 1852, 3^ lb. : Bull-trout 

 kelt, 3 lb., March, 1852, recaptured Shields, April, 1852, 4.^- lb.: three Black-tails^' Autumn, 1858, 

 recaptured at Aberdeen, one in the Don, and two in the sea as Whitlings from 2 lb. to 3 lb. : Black- 

 tail, 1 lb., Sept., 1870, as Bull trout. North Esk, 2 lb. 1 oz., Sept., 1871: Black-tail, 12 oz., Oct., 

 1870, as a BuU trout, 2 lb. 10 oz., at Lamberton, June, 1871 : Bull trout, 3^ lb., Oct., 1870, recaptured 

 in Coquet, 4 lb. 13 oz., Nov., 1871 : Black-tail, 1 lb., Oct., 1871, as Bulftrout, 1 lb. 7 oz., Stirling, 

 August, 1872: Black-tail, 18 oz., Sept., 1872, as Bull trout, 36 oz., Dee, July, 1873: Black-tail, 

 12 oz., Oct., 1872, in Whitadder as Black-tail, 12 oz., Nov., 1872 : Black-tail, 13 oz., Nov., 

 1875, as Bull trout, Stirling, 28 oz., July, 1870 : Black-tail, 13i oz., Oct., 1876, in Firth of Forth 

 as Buh trout, 1 lb. 12i oz., August, 1877 : Black-tail, 8 oz., Oct., 1877, in Firth of Forth as Sea 

 trout, 1 lb., July, 1878 : Black-tail, 9 oz., Nov., 1877, in Firth of Forth as Sea trout, 2 lb. 4 oz., 

 July, 1878. 



I Mr. M. Dunn, Land and Water, June 24th, 1880, observed that he had found Pcal feeding 

 on herring-fry in Mevagissey Bay during the months of May and June. 



