38 U. S. BUREAU OF FISHERIES 
BRISTOL BAY SALMON FISHERIES 
The Bristol Bay area, w hich produces more than 60 percent of the 
pack of red salmon in Alaska, is one of the greatest salmon- ive oducing 
districts in the world. During 1939 this area produced 5414 million 
pounds of canned salmon. This pack was 5 million pounds below 
the average for the preceding 10 years, the curtailment being due, 
in part, toa shortening of the fishing season by the Bureau in P order 
to insure the escapement of an adequate number of spawning fish to 
the tributaries in the various watersheds. 
The determination of the causal factors affecting the fluctuation 
in abundance of the salmon runs in this region is ‘the fundamental 
purpose of the investigation being conducted by Mr. Kelez and 
Joseph T. Barnaby, assisted by W ‘alter Sands, Albert Collier, and 
abst Hacker. The problems entailed in the investigation are mani- 
fold, including a complete study of the life history of all the races 
of salmon populating the lakes and rivers in a watershed of over 
55,000 square miles. In addition to the studies on the fresh-water 
phase of the life history of the red salmon, studies must be made of 
the factors that influence the growth, mortality, and migrations of 
these fish during their sojourn in the ocean. 
Presh-water studies.—Investigations of the fresh-water phase of 
the life history of the red salmon of the Bristol Bay region were 
carried on during the season of 1939 at field camps established on 
5 of the main rivers during the summer, and on the watersheds of 
these streams during the fall. A camp at the foot of the Naknek 
River rapids was established on May 19; 1 at the head of the Ugashik 
River lagoon on May 24; 1 on the Kvichak River, at the foot of Kas- 
konak flats, on May 25; 1 below the Egegik River rapids on May 27; 
and 1 on the Wood River at the foot of Marsh Mountain on May a 
Regular samples of seaward migrant fingerlings were taken at 
each camp, collections of other fishes were made, and fingerlings were 
marked for future identification in the rivers where they were avail- 
able in sufficient numbers. Daily records of weather conditions, 
stream levels, and air and water temperatures were kept throughout 
the season until the parties moved to the upper watersheds for spawn- 
ing observations. The stream observations will be correlated with 
annual meteor ological data collected by the U. S. Weather Bureau at 
3 stations in the Bristol Bay region. 
The spring break-up was very late in 1939, particularly in the 
Wood River watershed, where ice, carried down from the Wood River 
lakes, seriously interfered with seining activities as late as June 13. 
Fingerlings were available in sufficient quantities to warrant mark- 
ing only in the Naknek and Wood Rivers, although small numbers 
of migrants were taken in the other streams. 
Migrants were taken in the Naknek Riv er from May 31 to August 
15, but less than 100 per day were caught prior to June 14. Marking, 
by excision of the dorsal and right ventral fins, was begun on June 
16 and terminated on August 14. All marked fish were retained in 
holding pens for 24 hours after marking in order that the losses due 
to handling might be determined. The total release of marked fish 
in this area was 26,419. The Naknek fingerlings were large, averag- 
ing about 113 mm. in length, and were in good condition ; losses due 
