THIRTEENTH ANNUAL MEETING. 169 
The conclusions deducted by him from the discussion of the 
data presented were as follows: 
The temperature records of 1881, ’82 and ’83 indicate that for 
the winter months the area of maximum temperature is not in 
the rivers or in the bay, but on that ocean plateau outside, ex- 
tending from the capes of the Chesapeake to the Delaware 
breakwater. The presumption, therefore, is that the schools of 
shad belonging to both the Chesapeake and the Delaware, have 
their common winter quarters on this plateau. When under the 
influence of the advancing seasons the waters of the Chesapeake 
and the Delaware bays become warmer than on this plateau, the 
migrations into continental waters begin. The proportion of 
the entire run that will be directed to the Delaware or the Chesa- 
peake, will be determined at this time, “If the northern end of 
the area warms up more rapidly than the southern, then an un- 
usual proportion of the shad will be thrown into the Delaware. 
On the other hand, cold waters coming down the Delaware, may 
effect a contrary movement, and throw the schools of shad al- 
most entirely into the Chesapeake; thus leading to a partial or 
total failure of the the shad fisheries of the Delaware for the 
season. 
When the schools of shad have entered the Chesapeake, their 
distribution to the rivers will be determined in the same way by 
temperature influences operating. If the season i$ backward, so 
as to keep down the temperature of the larger rivers which head 
back in the mountains, then the run of shad will be mainly into 
the shorter tributaries of the bay, which have their rise in the 
tide-water belt, and which, of course, are warmer at this season 
than the main rivers. . 
Again, warm rains at the beginning of the fishing season in 
our large rivers, and the absence of snow in the mountains, will 
determine the main movement of the shad into the larger rivers 
of the basin; and if, when the schools enter the estuaries of these 
rivers, they encounter a temperature considerably higher than 
that in the bay itself, the movement up the river will be tumult- 
uous; the schools of shad and herring all entering and ascend- 
ing at once, producing a glut in the fisheries such as we some- 
times have recorded. 
