AQUATIC PLANTS IN POND CULTUEE. 27 



At this season the growth of vegetation is not so exuberant as hiter 

 in the summer, and the first crop of fish may sometimes be collected 

 by seining around the edges of the ponds without the preliminary 

 clearing aw^ay of the vegetation. Often, however, the shallower por- 

 tions of the ponds must be cleared before even the first crop of fish 

 can be removed. Later the fish will have sought the deeper portions, 

 from which they can not be removed without first drawing off the 

 water. In the latter process the foliage, if left, would settle down as 

 the water diminished, entangling the young fish or smothering them, 

 and it is accordingly necessary to clear away the plants before draw- 

 ing off the water. The methods of removing the foliage are thus 

 reduced to a mowing process under water, varied and adapted as 

 conditions and circumstances may demand and ingenuity may devise. 

 The methods and apparatus here described have been employed at 

 pond culture stations, but are also applicable to natural ponds where 

 the character of the bottom permits of seining operations. 



At the Fish Lakes station the removal of the aquatic foliage was 

 accomplished by mowing with ordinary scythes such as are used in 

 a hay field. The shallower portion of a pond was mowed first, and 

 the water was then partially drawn off so that it did not reach above 

 the armpits of the mowers, its average depth being from 3 to 4 feet. 

 The cut foliage rose to the surface and was carried to the shore in 

 boats. 



When it is desired to transfer young fish from the ponds at North- 

 ville, Mich., the slash boards are removed from the overflows and 

 the water drawn down. As it recedes from the banks a few feet 

 men rake the Chara into piles, taking care that no young fish are 

 destroyed in the operation, and continue this process until all the 

 water and young fish are confined to the kettle of the pond. It was 

 formerly customary to remove the vegetation by the use of teams, 

 but recent experiments show that if left exposed for two weeks the 

 Chara settles and finally disappears after the pond has been refilled. 

 The presence of this decaying vegetation ought to stimulate the breed- 

 ing of more or less insect life for young fish to feed upon. 



The method of separating plants and young fish at the Mill Creek 

 station of the Michigan Fish Commission is described by the superin- 

 tendent, Mr. Dwight Lydell, in substance as follows: A space 10 feet 

 wide around the pond is first cleared of foliage with a common iron- 

 toothed garden rake, a piece of galvanized wire netting of one-fourth- 

 inch mesh being fastened to the back of it to prevent its becoming en- 

 tangled in the weeds. (Any tinsmith can solder the wire cloth to the 

 iron back.) After this has been done a homemade rake is used to 

 remove the foliage from the deeper water of the pond. The rake is 

 of rude construction, consisting of a cedar pole 8 feet long and 4 or 5 

 inches in diameter, provided with teeth 6 inches apart and 12 inches 



