REPORT OF COMMISSIONER OF FISH AND FISHERIES. XV 
has continued for many years, and has resulted in the accumulation of 
a large amount of valuable information. During 1886, these observa- 
tions were carried on at thirty-six light-ships and light-houses, and at 
forty-eight stations of the Signal Service. 
Rusty mackerel.—The rusting of mackerel, which sometimes occurs 
when, through the leaking out of the brine in which they are preserved 
in barrels, they are left more or less exposed to the air, has been a 
source of frequent loss to the fish dealers. The character and precise 
cause of this peculiar change being unknown, specimens of rusty mack- 
erel were obtained during the year and submitted to Prof. W. O. At- 
water, of Middletown, Conn., for examination. His report upon the 
subject has not yet been received. ‘ 
Disease among trout.—The investigations by Prof. S. A. Forbes, of 
Illinois, of specimens of trout from Baird Station, Cal., affected by a 
disease hitherto unknown in that region, proves that the disease is 
identical with that found among the herring in Madison Lakes, Wiscon- 
sin, where it was very wide spread and destructive in 1884. Mr. Forbes’s 
report will be found in the account of McCloud River station, by Liv- 
ingston Stone. 
C.—PREPARATION OF REPORTS, ETC. 
The study of materials and the reduction and compilation of observa- 
tions made by the field parties, including the preparation of reports 
upon the same, was continued during the year at the Washington and 
Wood’s Holl stations of the Commission and at many college labora- 
tories. As heretofore this class of work was done mostly by volunteers, 
among whom are some of the most accomplished naturalists of the 
country. Prof. A. E. Verrill has had general charge of the collections 
of marine invertebrates obtained along the Eastern coast, north of 
Cape Hatteras, which he is studying in their relations to the fishing 
grounds. The fishes were being treated in a similar manner by Prof. G. 
Brown Goode and Dr. T. H. Bean. Other special subjects were in- 
trusted to the following persons: The crustacea to Prof. S. 1. Smith; 
the bottom deposits to Prof. L. A. Lee; the internal parasites of fishes 
to Prof. Edwin Linton and Prof. B. F. Koons; the crustacean parasites 
of fishes and the temperature results to Mr. R. Rathbun; special groups 
of the mollusca and the preparation of charts to illustrate the marine 
investigations of the Commission to Mr. Sanderson Smith; embryolog- 
ical work respecting the cod, lobster, and oyster and other economic 
species to Prof. John A. Ryder; the preservation of bait to Dr. J. H. 
Kidder and Mr. Rathbun. 
D.—PROPOSED EXTENSION OF THE INQUIRY TO THE PaciFIc Coast, 
The first extensive fishery investigations made upon the Pacifie coast 
of the United States were undertaken by the U.S. Fish Commission 
in connection with the Tenth Census, beginning in 1879 and extending 
