[135] roNij CU1/HKE. {]()\ 



full. Ill tliojsc cases t lie bed of the hiodk is, accordiiif;- to eiieiiinstiinces 

 widened i to 1 meter, and al)()iit 1~> eeiitinieters fall is ftiveu to every (> 

 meters len.yth. The de])(li of water should not l»e below 10 or above 



00 centimeters. The bottom is covered with coarse gravel to the height 

 of 10 (H'litimeters. The ditch must slope gradually towards the bottom 

 of the i)ond. If the fall is nu)re than 13 centimeters in meters, a few 

 boards may be ])laced across the ditch or brook, which at one side have 

 an opening for the fish to pass through. The depth of water, however, 

 should not be raised by these boards above that given before, as the 

 trout like to spawn in shallow water. The boundary line of the spawn- 

 ing place should be iiulicated by ii ver^' narrow^ grate, so the fry cannot 

 escape and go up the stream to the spring. Above this narrow grate 

 there should be a common grate for keeping oil" mud, dry leaves, «&c. 

 After the trout have dej)osited their si)awn they are driven back into 

 the pond, and the spawning ditch is also closed towards the jjoiuI by a 

 very narrow grate. In this spawning ditch the fry are left for one year ; 

 or if the old trout have si)awned ])articularly early, the fry may be 

 ])laced in a pond in spring. If the natural condition of the spring or 

 brook which serves as a si)awniug place meets all the requirements 

 mentioned above, nothing need be done but to fence off the spawning 

 place by grates. To i)roleet the eggs and fry against their enemies, the 

 spawning ditch is covered with dry biush-wood, but not so close afe to 



1 present a current of air from jjassing through. Every year, before the 



spawning season commences, the ditch should be cleaiuul of mud and 



, aquatic plants. As soon as the young fish have slii)ped out of the eggs, 



hidiiig-i)laces should be provided for them, which can easily be done 



by placing in the water good-sized stones, hollow tiles, <S:c. If tlierii 



* are no aquatic i)lants, such as water-cresses — wdiich, if not found in 



the ditch, should by all means be planted — and if there are no shrubs 



i| or trees on the banks to aflbrd sliade, the covering of brush-wood 



J should be made thicker in some places. To i)rovide both currents and 



j calm places, small boards are placed in the ditch at suitable i)laces, of 



,; course with openings for the little fish to pass through. The temi)era- 



. tare of the water in the spawning ditch should not exceed 12° 1{. [oO^ ¥.]. 



j Seventeen degrees are dangerous, and 23 become fatal. To prevent a 



,; rise of temperature in very hot weather, more brush-wood can be i)iled on 



1 the ditch. The fry need not be fed, if there is in the ditch a sullicient 

 . quantity of aquaticplants such as Lemnacecc, Na,sturtium officinale {Wcitav- 

 j cresses), Veronica beccahunga, &c., for these plants are always inhabited 

 I by numerous diminutive animals which serve as food for the fry. These 

 i plants are planted in the ditch simply by laying the roots on the bottom 

 land i)lacing stones on them to prevent tie water from carrying theui 



I off. It is also advisable to introduce into the «litch insects, es])ecially 



I of the genus (lamninrns^ which is done in a vei-y simple manner, by 



• atchiiig these insects in stagnant water, where in the beginning ot 



spring they are found in enormous numbers, and transferring them to 



the ditch. 



