The Productivity of Fish Food in Oneida Lake 141 



The authors note that the ground was also paved with 

 Sphcrrium and that the area examined gave a fair average of 

 individuals for the population of the canal. 



The averages per square yard for the first two units cited 

 are 6.9 and 9.4 respectively. The last unit, a square meter, 

 averages 115.4 per square yard. Compared with the first 

 two examples the Lower South Bay average of 7.8 for shallow 

 water (1-6 feet) and 16.8 for deeper water (6-14 feet) is 

 very favorable. In the third example, however, the average 

 is very much greater than in any part of Oneida Lake. The 

 gastropods in the last unit (57) are very much less in number 

 of individuals than usually occurred in the units in Oneida 

 Lake. As no attempt was made by the authors to count all 

 of the animal life a comparison other than for the mussel 

 population is not fair. 



Comparison with Marine Valuations. It will be of inter- 

 est to compare some of the numerical valuations of Oneida 

 Lake with those of marine bottom areas. Blegvad ('17, p. 22) 

 gives the number of animals per square meter from the bottom 

 of two Danish habitats (Table No. 36). For comparison the 

 animals from the 16 square inch units of two habitats (a good 

 and a poor habitat numerically) in Oneida Lake have been 

 listed (Table No. 37) and the number of animals have been 

 increased to the square meter valuation (by multiplying by 

 96.87, the number of 16 square inch units in a square meter). 

 It will be noted that in both Oneida Lake examples the number 

 of animals greatly exceed those from the marine unit areas. 

 When we compare the Oneida Lake unit valuations with the 

 marine population per square meter of vegetation {Zostera 

 plants) the number of marine animals greatly exceeds those 

 from any similar area of fresh water yet examined by me. 

 Blegvad ('17, p. 23) collected with a hand net over one square 

 meter of Zostera, at 2 meters depth (about 6^ feet) and 

 obtained 84,494 mollusks and 96 associated animals. Of 

 the genus Rissoa, small mollusks comparable or ecologically 

 equivalent to the Amnicola of Oneida Lake, two species 

 totalled 84,420 individuals. 



