REPORT OF COMMISSIONER OF FISH AND FISHERIES 49 
with proper facilities Dr. Dean is confident that he could have produced 
enough fry to have made his work exceedingly profitable from a prac- 
tical standpoint. Heconsiders the vicinity of Delaware City especially 
well adapted to the propagation of the sturgeon, and thinks there 
would be no trouble in securing a sufficient number of spawning fish at 
the proper season. He was there from May 14 to 23. Observations | 
were also made respecting the breeding and other habits of the stur- 
geon, and Dr. Dean has now in course of preparation a comprehensive 
account of the results of his investigations. 
MORTALITY AMONG ALEWIVES, LAKE ONTARIO, 
Reference has frequently been made in the Fish-Commission publi- 
cations to the extraordinary mortality which occurs among the alewives 
in Lake Ortario during every spring and summer, and which also, to 
some extent, affects other common fishes in the same waters. The cause 
of this annual epidemic has never been determined; it has a widespread 
distribution, and the number of dead and dying fishes which are often 
cast upon the shores in some places is se great as to occasion much 
inconvenience to residents and summer visitors from the unpleasant 
odors arising from the decaying bodies. Mr. C. H. Strowger, of Nine- 
Mile Point, near Webster, N. Y., has paid a great deal of attention to 
this phenomenon, and the Fish Commission is indebted to him for much 
information respecting it, as well as for specimens of the diseased fish. 
In order to reach a more.complete understanding of the subject, Dr. R. 
R. Gurley was dispatched to Lake Ontario in the early part of June, 
1893, and remained there about a month, visiting Nine-Mile Point, 
Wilson, Charlotte, and Cape Vincent. He spent the most of this time 
at the place first mentioned, where laboratory accommodations were 
supplied by Mr. Strowger, who also assisted Dr. Gurley personally in 
his investigations. 
From the statements of persons living along the shores of Lake 
Ontario, the epidemic appears to begin in April, occasionally as early 
as the latter part of March, reaches its maximum in May, and decreases 
through June, although in some cases it may be found as late as August. 
The May and June maximum of the epidemic coincides with the period 
when the alewives are most abundant inshore. The diseased fish have 
a patch of saprolegnia, usually from three-fourths of an inch to an inch 
in diameter, 0n some parts of the body, but no other parasites were 
found on any of the dead alewives examined. None of the vital organs 
were affected by the fungus, the gills in particular always appearing 
clear, and otherwise also the fish seemed to be in good condition. An 
inflamed area was almost always noticed on the general surface of the 
body under the patch, of saprolegnia, and very generally a sore or ulcer, 
the scales in such places being loosened or detached. In some cases 
the fungus appeared to have effected a lodgment in places where the 
F. R. 93——4 
