860 



SCANDINAVIAN FISHES. 



jirc regular lock-weirs, with sluices abov<! and below, tlie 

 fbi'iner in two rows. The u})])eruiost row (a) is merely 

 a grating, which continually lets the water through, 

 as well as the gates (c) at the lower end. TJie latter are 

 let (Inwii only when tiie watertight gates in the second 

 row at tiie upper end (/>) are shut, the water now running 

 out, l)ut the fish being left behind. In tlie fiiihi/fff/iiadcr 

 large Salmon-traps {thtor) are set. wliich ari' lifted witii 

 a hoist when they are to be examined". Tlie n-((l,-JNis 

 are, strictly speaking, large kar (see above, Salinon- 

 jjens), constructed lieside a race. So manifold are these 



Fig. 217. A Sahiiou 



contrivances that Sweden, to her cost, can boast of 

 her \\'ealth of devices for the taking of Salmon. 



In order to counterbalance the destruction M^rought 

 by these engines, and to extend the run of the Sal- 

 mon by enabling them to surmount falls otherwise 

 im|)assal)le, SdlnHDi stairs are built. In these the force 

 of the water is diminished by transverse walls pro- 

 jecting alternately from the sides, and extending across 

 more than half the -width of the staircase but not 

 reaching to the opj)osite side. The stairs may be erected 

 beside a fall in many different modes, according to 



the nature of the locality; but care should Ise taken 

 to avoid ])lacing the lower opening of the stair in the 

 same direction as the fall, and to turn it obliquclv 

 across the stream or, .still better, straight against the 

 current. 



The River Trout too — even those which pass 

 their whole life in brooks and small streams — rove 

 to the spawning-place. "In a valley not far from my 

 native place," says 1>kehm'', "there rise co])ious springs, 

 AN'hich together form a brook that has power enough 

 to drive a mill-wheel. This brook falls into the Roda 

 and clears the water of the latter, which is sometimes 

 rather thick. As long as can be i-emembered. Trout 

 have lived here, but oidy for an extent of at most 

 eight kilometres. Above and below this ]iart of the 

 brook they do not occur, as a general rule; and oiih- 

 during the spawning-season does it happen that thev 

 abandon their true home and rove to rocky parts of 

 the Roda in quest of breeding-places, though they have 

 equally good sjtots in their usual haunts." The spawn- 

 ing-dress of the River Trout sometimes includes a l)lack 

 coating on the forepart of the bodj*, such as that we 

 have above remarked in the ("hari's. 



The longer marine Salmon remain in the rivers, 

 the more tumid are their generative organs, and the 

 darker their dress. Our tigiu'es show the a]i])earance 

 both of the true Salmon (Plate XXXVII, figs. 3 and 4) 

 and the Sea Trout (Plate XXXIX, figs. 1 and 2) at the 

 beginning of these alterations; but at the end of their 

 wanderings, when the spawning-season commences, they 

 have assumed (|uite a different colour, of much darker 

 tone, as depicted by v. Whight in his figure (Plate 

 XXXIX, fig. 3) of a female Sea Trout {(Jrinff) in fresh- 

 water dress. The belly of the males becomes entirely 

 red. In old males of the true Salmon the margin of 

 the caudal fin is also straightened, without a trace of 

 indentation, or even, like the margin of the anal fin, 

 convex. By a retrogression to the characters of j'outh, 

 they are besides approximated to the Sea Trout in the 

 characters relating to the least depth of the tail and 

 the height of the anal fin, otherwise the most constant 

 distinctions between the two varieties. 



In September the spawning-season begins. The 

 old fish commence fii'st. The young sometimes wait 

 even till the followinsr March. And among the latter 



" See GiSLER, Vet.-Ak.ad. Hr.iull. 1752, tab. I. 

 ' Thierleben, 1. c, p. 227. 



