Report of Experiments on the Salmonidce of the Tweed. 377 



They are also protected with lids or covers, and thus they 

 can be protected from rats and all other creatures that might 

 destroy them. This system is very favourable for any 

 gentleman who wishes to try breeding on a small scale. The 

 next stage is that of allowing them to leave the boundary 

 boxes to go into the adjoining feeding pond, where they are 

 kept in the " Parr " state for the first year. At the expira- 

 tion of that time, th/ey put on the "Smolt dress"; along with 

 which they seem to get their migratory propensity, and are 

 allowed to pass into the river; and during the months of May 

 and June seem all to find their way to the sea, where they 

 stay until the following year. The Salmon Smolts then 

 return as "Grilses," from 1J to 3 pounds weight; but rapidly 

 increasing in the sea, and, as the season advances, improving 

 in weight at the rate of one pound for every month that they 

 remain : so that, towards the close of the season, in Septem- 

 ber, many of them have attained the weight of nine pounds 

 or more. Most, if not all, of these fish spawn during the 

 following winter ; return to the sea as " Grilse Kelts " ; and 

 the following season return as adult Salmon. This has been 

 denied by some people, but they give us no proof of their 

 theory. The migratory Trouts go through, the same stage as 

 the Salmon ones, with.' this exception, that the Trout Smolts on 

 returning from the sea, come back as " Black-tails " or 

 " Silver-whites," retaining a good deal of the silvery dregs 

 with, which they left, but increased in weight to about 12 to 

 16 ounces. After this, they again return to the sea, and very 

 quickly return as " Whitling," or " Young Bull Trout," or 

 "Sea Trout"; having in the interval lost the silvery appear- 

 ance, and put on the large star-like spots peculiar to the 

 larger Trout mentioned above. 



These facts have been ascertained by carefully marking 

 the young fish in all the different stages of their growth, and 

 by keeping a proper register of all that are uncaptured on 

 returning from the sea. 



The following report of those coming back last season, as 

 reported by the Experimental Committee to the Tweed Com- 

 missioners, shows in what manner those experiments are 

 conducted, and gives also an idea of the proportion of the 

 smaller fish that are coming back from time to time. 



" The following tabular statements show — First, the particulars 

 relative to the fish which have been retaken ; and secondly, the 

 number and species of the fish marked between September, 

 1870, and June, 1872, inclusive: — 



