XX REPORT TO THE SECRETARY OF COMMERCE 
on the oysters in Georgia, North Carolina, South Carolina, Missis- 
sippi, and Texas; salmon investigations in California, Oregon, and 
Washington; a study of food supply in lake waters in Michigan and 
Wisconsin; and mussel investigations in Arkansas. 
Following is a brief résumé of the results of the more important 
activities of the division: 
INVESTIGATIONS OF THE FISHERIES OF THE NORTH ATLANTIC 
Tagging operations in the summer of 1926 were continued from 
August to October, the total number of cod, haddock, and pollock 
tagged amounting to 4,235. The work was carried on from the fish- 
eries steamer Albatross IT, chiefly in the waters south of Cape Cod, 
on Georges Bank, and off Mount Desert, Me. ‘The tagging work was 
resumed in April, 1927, the program including further tagging on 
Georges, Browns, and Fippenies Banks as well as on the inshore 
grounds in Massachusetts Bay and along the coast of Maine. Three 
cruises were made before the close of the fiscal year, during which 
3,602 cod, pollock, and haddock were tagged, bringing the total of the 
fiscal year 1927 up to 7,847, and for the entire experiment since 1923 
to 48,699. The recapture of tagged fish during the present season has 
been satisfactory, but a greater proportion is expected during the 
autumn and winter. 
During the spring operations an otter trawl was used with consid- 
erable success, even on rocky grounds, for taking the smaller cod and 
securing a better representation of the immature members of the 
population: An extensive collection of scales has been taken; many 
of them have been studied, and the intensity of fishing and the size 
and age composition of the stock on the grounds has been determined. 
In order to determine further the interdependence of the various 
fishing banks, studies of the abundance and distribution of cod eggs 
in Massachusetts Bay have been continued, and a report covering 
the observations made during 1924 and 1925 from the Fish Hawk 
has been completed. 
Through extensive observations of the commercial run of mackerel 
at several of the major ports, an understanding of the composition of 
the mackerel stock entering the commercial fishery has been gained. 
The studies of the spawning areas also have been continued. Ob- 
servations on the southern fishing grounds, from Long Island to 
Delaware, were made during the spring of 1927, and through system- 
atic tow-net collections of eggs and larve an attempt is being made 
to discover the relative success of spawning each year. At the same 
time the tagging experiments to trace the migrations of the fish have 
been continued, and it is confidently expected that through the early 
detection of successful spawning years, and from knowledge of the 
biology of the fish and its habits, the extent of future runs may be 
predicted. 
Both fresh and salt water smelts are being studied. The salt-water 
smelts are suffering rapid extermination, and these studies of life 
history and habits, as interpreted by modern methods of fishery 
research, will provide the basis for definite recommendations for 
regulation of the fishery. In addition, extensive collections of trouts 
and chars, made in many localities through North America, are re- 
