AQUATIC PLANTS IN POND CULTURE. 31. 



exuberantly from bottom to surface and is removed by the use of a 

 wire, about the size of a telegraph Avire, loaded with weights and 

 pulled through the pond much as a seine is hauled, except that it is 

 jerked vigorously from side to side. In this way the tender growth 

 of the Myrlophyllum is easily severed. It is then dragged ashore 

 wdtli a long rake similar to the one in use at San Marcos. The super- 

 intendent prefers this method to the use of a scythe. 



Owing to the necessity for periodically removing the aquatic foli- 

 age at pond-culture stations and the expense involved in the present 

 methods of performing this task, it is obvious that here also is a field 

 for experimentation. In this connection it seems proper to refer to 

 the success of Mr. Charles T. Allen, who some years ago devised an 

 aquatic mowing machine for the purpose of cutting eel grass on 

 oyster grounds." Mr. Allen asserts that the machine will cut 2,400 

 square feet of grass per minute in water 6 feet deep. Undoubtedly 

 the machine is too large and heavy for use in small ponds, but it 

 might perhaps be modified to suit the requirements of pond culture 

 if the cutting knives can be successfully used on the vegetation of 

 ponds. Gasoline or hand power could be substituted for steam power. 



° Report of the United States Commission of Fish and Fisheries for 1892, p. 477-478. 



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