BUREAU OF FISHERIES 155 
Hudson indicate that the great majority of shad return to the same 
river year after year. Additional data on this point are being 
athered by extensive analysis of the racial characteristics of shad 
rom the different rivers. 
Because of the importance of reproduction in shad conservation a 
careful ecological study of the early life history is being made in 
southern rivers. In 1938 intensive work was done in the Edisto and 
in 1939 these studies were extended to other rivers. 
Shrimp investigations Studies of the shrimp fishery consisted of 
several cruises to assess available supplies in the offshore waters of 
the Gulf of Mexico, a continuation of tagging experiments to deter- 
mine the seasonal migrations of shrimp along both the Atlantic and 
Gulf coasts, and ecological studies of the relationship between en- 
vironmental changes and the distribution of shrimp along the Texas 
coast. 
As a result of a cruise of the Pelican along the Louisiana’ and 
Texas coasts in January and February, the presence of shrimp off 
the Louisiana coast in concentrations sufficient to warrant commercial 
exploitation was confirmed. No large concentrations of commercial 
shrimp were found off the Texas coast. In a later cruise a similar 
lack of commercial shrimp was observed off the coasts of Alabama 
and Florida between Mobile Bay and Apalachee Bay. 
Tagging of shrimp on the Atlantic coast from Cape Canaveral to 
St. Augustine, where the bulk of the South Atlantic coastal shrimp 
congregate for the winter, gave evidence of a return movement at 
least as far as 250 miles northward. Other tagging experiments 
indicated that the small shrimp do not engage in coastwise migra- 
tions as extensively as do the larger sizes. 
In cooperation with the Texas Game, Fish, and Oyster Commission, 
a program of hydrographic surveys and experimental trawling was 
instituted in Aransas Bay to determine the extent to which hydro- 
graphic factors may control the distribution of shrimp and day-to- 
day fluctuations in the catch. 
North Pacific and Alaska fishery investigations——Commercial fish- 
ery investigations in northern Pacific waters form the basis of recom- 
mendations for the management and conservation of the salmon 
runs in the rivers of the Northwestern Coastal States. They are also 
concerned with maintaining at a productive level the salmon and 
herring fisheries of Alaska, over which the Federal Government has 
regulatory power. 
The activities of the Columbia River staff have centered about 
the problem created by the erection of Grand Coulee Dam, blocking 
that portion of the Columbia River salmon run that normally spawns 
in tributaries of the upper Columbia. Salvage operations were begun 
in 1939. The runs are being trapped at Rock Island Dam, 150 miles 
downstream, and transferred in specially constructed trucks to tribu- 
taries between Rock Island and Grand Coulee Dams. It is hoped 
that the fish will spawn in these tributaries, and that their progeny 
will later return to them. If the plan yields the anticipated results, 
the entire run of upper Columbia fish will be transferred to tribu- 
taries below Grand Coulee within a period of 5 years, or the life 
cycle of a salmon. 
