178 SALMONIDyE OF BRITAIN. 



the following instances from tlic Tweed experiments eliminated doul)tful cases 

 and restricted my cxani]iles to such as have 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 li 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 li 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 IH oz. in weight 

 had actually decrea.scd to 10 oz. in six months, and a second from 10^ oz. to 6 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 

 25 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 rivei' wherein the marked fish have 

 been captured in distant localities, wo find fi'om the observations of the Tweed 

 Commissioners,t that these fish migi'ate 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 h 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. 



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

 in some I'espects they seem to be more voracious. 



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

 .shire Dec, taken in July, 1882, four sand launces, Amniodylcs.X Sir W. Jardine 

 found its common food to lie the sand hopper, TaKtriis locusta. Phinocs in rivers 

 arc partial to the fresh-water shrimp Gammarus pulex. That they will 

 consume fish eggs is well known, thus Bertram (p. IVI'J) recoi'ded how a whitling 

 in 1882 of aboufi j lb. weight had been taken in the Tay with 300 salmonoid eggs 

 in it,s 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 from the Cathedral of St. ilachar to where the 

 river discharges itself into the sea. 



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

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



* Orange fin or trout smolt marked April or May, 1851, became a clean BuU trout 5 lb. weight, 

 May, IS,''.! : Smolt, Mav, 18,57, a Bull trout, 3 lb., May, 1858 : Black-tail, October, 1859, a Wbitling, 

 l.i. to 2 lb., Mai cli, isiu'; Wliitling, IJ lb., Soptember, 1870, a WliitUng, 2i lb., .July, 1872 : Bull trout, 

 21 lb., Sept. 2()tli, 1870, to a Bull trout, 5J lb., August, 1871 : Black-tail, 12 oz., October, 1870, to a 

 Whitling, 17 oz., June, 1S71: Black-tail, 21 oz., October, 1871, a Whitling, 2.^ lb., August, 1872 : 

 Orange fin, 1-J oz., April. 1873, a Whitling, 1 lb. 8 oz., June, 1H74 : Black-tail, "J oz., Sept., 1873, a 

 Whitling, 1 lb. 3 oz., June, 187 1: Black-tail, 14.^ oz., Nov., 1877, a Bull trout, 28 oz., August, 187'J : 

 ]!lack-tail, 13 oz., Nov., 1H77, a Bull trout, 4,Ub., May, 187'.l : Black-tail, 11 oz., Nov., 1875, a 

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

 1878 : Black-tail, 11 oz., Nov., 1877, a Bull trout, 2J lb.", August, 1H79 : a Black-tail, 10^ oz., Nov., 

 1875,aBtack-tail,8.i oz., March, 187(i: Black-tail, 11.5 oz., Nov., 1877, a Black-tail, lOoz., April, 1878. 



t Bull trout kelt, 3 lb., March, 1852, recaptured at Yarmouth, April, 1852, 3A lb. : Bull-trout 

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

 reca])tnrcd 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 Bull trout, 2 lb. 10 oz., at Larabcrton, 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 BuU 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, 187<1 : Black-tail, IS.J oz., Oct., 1870, in Firth of Forth 

 as Bull trout, 1 lb. I25 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. 



t Mr. M. Dunn, T.fitid and Water, June 2tth, 1880, observed that he had found I'cal feeding 

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



