566 
therefore the weight, of the marketed catch. Some correspond- 
ence in plankton and the products of the fisheries might there- 
fore be expected, though on account of the complexity of the 
problem and the limitations of our data it is difficult to demon- 
strate it in every Case. 
In 1894, when our data indicate a plankton production be- 
low the average in channel, in backwaters, in their sum, and in 
the estimated discharge, we find the total production of mar- 
ketable fish also below the average (for 1894-1898). In 1895 
our collections indicate an increase, approximating 50 per cent. 
in plankton production as exhibited by each of the methods 
tabulated, and there is also an increase in the product of the 
fisheries, though it amounts to only about 4 per cent. The 
direction of the change in production is the same in all cases. In 
1896 plankton production falls in channel, in backwaters, in 
their sum, and in total discharge, the decline in all but the back- 
waters being greater than the increase from 1894 to 1895, and 
we find, accordingly, that the decline in the product of the tish- 
eries is also greater than its antecedent rise to the level attain- 
ed in 1895. In 1897 plankton production again rises in the 
channel, in the sum of channel and backwaters, and in total 
discharge, but not in the backwaters. This apparent decline in 
backwater production may be due to the elimination from our 
data, for a part of the year, of Phelps, Flag, and Dogfish lakes, 
thus giving undue weight to the depressing effect of the Quiver 
Lake data. The fact that in Thompson’s Lake plankton pro- 
duction rises from 6.67 in 1896 to 10.41 in 1897 is an indication 
that plankton production in the open backwaters in 1897 rose 
above the level of that of 1896. In correspondence with the 
increased plankton production in channel, and total discharge, 
we find the product of the fisheries rising from 7,252,811 pounds 
in 1896 to 9,703,298 in 1897—a change not exceeded in any 
other year of the records. In 1898 the product of the fisheries 
continues to increase, reaching 10,647,466 pounds, but plankton 
production rises only in the backwaters and in the sum of chan- 
nel and backwaters, falling in channel and total discharge. 
