The parr attains a size of from 34- to 8 inches. When the time of its migration comes, usually in May or June, it assumes brilliant silvery hues, the fins also becoming darker, and is then known as a smolt. Groups of smolts, 40 to 70 in a group, now descend not very rapidly, to the sea. They remain for a short time in brackish water, and then depart from the estuary. Of their life in the sea nothing is known, except that they increase in size with wonderful rapidity; for it has been found that smolts which had been marked, returned to the same river in six or eight weeks as grilse of three to five pounds, or after a longer period even of eight or nine pounds.. Some re ascend the river when only a pound and a half or two pounds weight; and these are in some places known as salmon peal. Grilse are captured in great numbers in the latter part of summer and in autumn, but very few are seen in the earlier part of the fishing season. The grilse usually spawns on its first return to the fresh water—often remaining there for the winter. rind on again descending to the sea assumes the perfect characters of the mature salmon. Little increase of size ever takes place in fresh water; but the growth of the salmon in the sea is marvelously rapid, not only on its first migration, but afterward. A keit caught by the late duke of Athole on March 31st weighed exactly ten pounds. It was marked, and returned to the Tay, in the lower part of which it was caught, after fire weeks and two days, when it was found to weigh twenty pounds and a quarter.
The statistics of salmon fisheries are, like those of other fisheries, very imperfect. It is impossible to ascertain the total annual value of the salmon fisheries even of Great Britain and Ireland; but it must be reckoned by hundreds of thousands of pounds. "From the reports of the Irish commissioners, we learn that in 1802, a,parently an ordinary year, three Irish railways conveyed 400 tons, or about 000,000 lbs. of salmon, being equal in weight and treble in value to 15,000 sheep, or 20,000 mixed sheep and lambs. In Scotland, the Tay alone furnishes about 800,000 lbs., being equal in weight and treble in value to 18,000 sheep (and lambs). The weight of salmon produced by the Spey is equal to the weight of mutton annually yielded to the butcher by each of several of the sandier counties. . . . . And in making comparisons between the supplies of fish and of flesh, it must be kept in mind that fish, or at least salmon, though higher in money value, cost nothing for their keep, make bare no pasture, hollow out no turnips, consume no corn, but are, as Franklin expressed it, `bits of silver pulled out of the water.' " (Russel, The ,.`'alinon, p. 12.) In 1870, the number of boxes of salmon sent from Scot land to London was 25,645; from Ireland, 7,064; from England, 1508. The other British species yet to be noticed iu this article are reckoned with the salmon itself in all that relates to salmon fisheries.
The salmon fisheries of the British rivers have in general much decreased in produc tiveness since the beginning of the present century, which is very much ascribed to the introduction of fixed or standing nets along the coast, by which salmon are taken in great numbers before they reach the months of the rivers to which they are proceeding, and in which alone they were formerly caught; it having been discovered that, salmon feel their way, as it were, close along the shore for many miles toward the mouth of ,a river, feeding, meanwhile, on sand-launces, sand-hoppers, and other such prey. It is
also partly owing to the destruction of spawning fish by poachers; and in no small meas ure to the pollution of rivers consequent on the increase of population and industry, and to the more thorough drainage of land, the result of which has been that rivers are or a comparatively small number of days in the year in that half-flooded condition in which salmon are most ready to ascend them. The last of these causes is the most irre mcdiable; but if the operation of the others were abated, it would not of itself be suffi cient to prevent a productiveness of our rivers much greater than the present. The efforts which have begun to be made by breeding-ponds (see PISCICULTURE) to preserve eggs and fry from destruction, and so to multiply far beyond the natural amount the young salmon ready to descend to the sea, promise also such results as may yet probably make the supply of salmon far more abundant than it has ever been. There is reason to think that the productiveness of the waters may be increased as much as that of the land.
The stake net is the most deadly of all means employed for taking salmon; and its use is prohibited in estuaries and on some other parts of the coast. It consists of two rows of net-covered stakes so placed between high and low water marks, that salmon coming up to them, and proceeding along them, are conducted through a narrow open ing into what is called the court of the net, from which they cannot find the way of escape. The.ertare, which is now illegal in all parts of Britain, is an inclosed space formed in the wall of a dam or weir, into which the salmon enter as they ascend the stream, while a peculiar kind of grating prevents their return. The nets employed for catching salmon in rivers and estuaries are of many different kinds. In many places a small boat, or salmon coble, is used to carry out a seine net from the shore, setting (shoot ing) it with a circular sweep, the concavity of which is toward the stream or tide, and men stationed on shore pull ropes so as to bring it in by both ends at once with whatever it may have inclosed. Coracles (small boats of basket-work or a light wooden frame covered with canvas and tar, or other waterproof material) are used in salmon fishing in the Severn and other Welsh rivers. Nets which a single man can carry and work are also used in many rivers and estuaries, as those called halves on the Solway, which may be described as a bag attached to a pole. Dogs have sometimes been trained to drive salmon into nets, and some dogs have attained great expertness in catching salmon with but any assistance.