So serious is the destruction of the spawn and fry of salmon, both by sea and fresh-water trout, that the Duke of Sutherland’s manager would willingly, were it possible, extirpate the entire breed of these fish.  “They commence,” he informs us, in a letter of 15th May 1843, “the moment the salmon begin to deposit their spawn, and in the course of the spawning season they devour an immense quantity of ova.  Indeed, at all other times of the year, they feed on the fry of salmon, and continue their destruction till the day the smolts leave the rivers.  I have often cut up trout, and got smolts in their stomach; and last week a trout was opened in Mr Buist’s fish-yard with four full-grown smolts in its belly.  From these and other similar occurrences, you may judge to what extent this destruction is carried on, in the course of a single year, in such a river as our Oykel, where I have killed seven hundred trout at a single hawl.”  We understand that, some years ago, when Mr Trap, (a most appropriate name,) the fishmonger in Perth, had the Dupplin cruives, he got about 400 whitlings (or sea-trout) in one day, all of them gorged to the throat with salmon fry.  The sea-trout of Sutherlandshire, like those of the Nith and the Annan, almost all belong to the species named Salmo trutta by naturalists.  They scarcely ever exceed, indeed rarely attain to, a weight of five pounds; and such as go beyond that weight, and range upwards from eight to twelve pounds, are generally found to pertain to Salmo eriox, the noted bull-trout of the Tweed.  The great grey sea-trout of the river Ness, which sometimes reaches the weight of eighteen pounds, we doubt not, also belongs to the species last named.  It is rare in the waters of the Tay.

In regard to the seaward migration of salmon fry, Mr Scrope is of opinion that some are continually going down to the salt water in every month of the year, not with their silver scales on, but in the parr state.

“I say, not with their silver scales, because no clear smolt is ever seen in the Tweed during the summer and autumnal months.  As the spawning season in the Tweed extends over a period of six months, some of the fry must be necessarily some months older than the others, a circumstance which favours my supposition that they are constantly descending to the sea, and it is only a supposition, as I have no proof of the fact, and have never heard it suggested by any one.  But if I should be right, it will clear up some things that cannot well be accounted for in any other mode.  For instance, in the month of March 1841, Mr Yarrell informs me that he found a young salmon in the London market, and which he has preserved in spirits, measuring only fifteen inches long, and weighing only fifteen ounces.  And again another, the following April, sixteen and a half inches long, weighing twenty-four ounces.  Now, one of these appeared two months, and the other a month, before the usual time when the