American Fisheries Society. 75 



is preferable. The slats of the weir occupying about four-fifths 

 of the natural waterway, will act as a barrier to raise the water 

 above its natural level, more or less. 



Construction — The trap is a V-shaped enclosure described 

 by the mathematical term, "re-entering polygon," made of slats 

 varying in dimensions with the size of the stream and the force 

 of the current. I used slats one inch square, planed on two sides, 

 driven into the bed of the brook vertically, about one-fourth of 

 an inch apart, and nailed to horizontal timbers or hewn logs. 

 This framework of horizontal timbers consists of one course 

 laid at water level and a parallel course at the extreme height of 

 the weir. The general idea of such a trap is the same as the pound 

 net, there being an opening of four or five inches in the angle 

 of the V. A gate can be an^anged in the entrance with a lever 

 reaching to some point obscured from the view of the entrapped 

 •fish, which can be lowered whenever the trap is approached for 

 inspection. This method of trapping trout is not new, but re- 

 quires more precautions than for the capture of other fish less 

 active and gamy, and a few words of caution to the inexperi- 

 enced may be desirable. Build your trap to resist the greatest 

 freshet the stream is liable to develop. The run of trout at such 

 times will be greatest. Be careful to get a foundation that will 

 not be undermined by the constant washing of the current be- 

 tween the slats. It is usually best to entirely surround the sides 

 of a trap with slats rather than to depend upon the natural em- 

 bankments. It is not necessary to use narrow slats for the sides 

 of the trap, as no water passes through them, and the only object 

 is to secure an enclosure from which fish can be easily dipped 

 out. For a stream six feet wide, I should build an enclosure 

 about six feet square, the V extending into the enclosure about 

 three feet. 



In many localities it will be found possible to dig' side ditches 

 above the trap and enclosures, at right angles with the stream, 

 in order to convey surplus water away from the trap and lessen 

 the danger of washout or inundation. The bottom of such 

 ditches should be considerably above low water mark to carry 

 ofif surplus high water. 



A convenient place for the pens is just above the trap, so 

 that the trout can be dipped from the latter into the former. They 

 are constructed of the same material of which the trap is made, 

 the upper side of the trap enclosure being used as the lower 

 side or end of a series of pens. These should be made in shape 



