The ProdudivUv of Fish Food in Oneida Lake 125 



odoraia. Leaves were examined in three hal)itals tlie result 

 of which is sliown in the Table No. 29. The actual area cov- 

 ered by water-lily leaves has been difficult to determine with 

 any degree of accuracy. The most satisfactory method has 

 been to estimate the number and size of isolated patches of 

 water covered with leaves and from this result try to arrive at 

 a conclusion regarding the amount of life present. These areas 

 are noted on the ma]) showing distribution of plants (figures 

 18-20). A careful C()mj)utation shows that the water-lily areas 

 cover about 855,000 square feet. The leaves are scattered so 

 as to average one leaf in two sc|uare feet, and there is therefore 

 a total of approximately 427,500 lily leaves. Animal life was 

 noted on three out of five leaves, and the inhabited leaves thus 

 number 256,500 and the total amount of animal life is com- 

 puted to be 424,507 individuals, of which 336,528 are mollusks 

 and 87,979 are associated animals.* 



In Habitat No. Ivi, the surface of the water in a group of 

 Typha angustifolia, embracing an area of 400 scjuare feet, was 

 covered with dead leaves of this Cat-tail, upon which consider- 

 able animal life found food and support. A single unit i(y\ 

 square inches) was examined giving the result shown in "liable 

 No. 30. The water was from one to three feet deep. If the 

 number of animals found in the unit area is indicative of the 

 whole area, there are 2,700 mollusks and 3,600 associated ani- 

 mals, or a total population of 6,300. 



In Habitat No. Ixxxvii, an area of Bur-reed (Sparc/aniiini 

 enrycarpum) of about 300 square feet borders the shore in 

 water 16 to 18 inches deep. Nine Ancyhis paraHcliis were 

 collected on this plant in a single unit (64 square inches). On 

 this basis there are 6,075 individuals of this mollusk on the 

 leaves of Bur- reed in this vicinity. { 



* Computation : 42 and 11-^32=1.31 mollusks and .34 associated 

 animals per leaf, X 256,500 lily leaves = 336,528 mollusks and 87,979 

 associated animals. 



t Computation : 400 square feet X 144 square inches = 57,600 square 

 inches -^ 64 square inches = 900 unit areas X 3 ^= 2,700 mollusks and 

 X 4 ^^ 3,600 associated animals. 



J Computation : 300 square feet X 144 square inches =^ 43,200 square 

 inches ^ 64 square inches = 675 unit areas X 9 ^= 6,075 mollusks. 



