PROGRESS IN BIOLOGICAL INQUIRIES, 193 591 



The preliminary scale work has shown that although 4-Year fish 

 are numerous, there is also a large number of 5-year fish in most of 

 the annual samples. Work is now being continued which includes a 

 study of the ages of fish from the two main rivers, the Nushagak and 

 the Wood. 



The field work during the past summer included an inspection of 

 all the principal fishing areas in Bristol Bay. Trips were made up 

 the Naknek and Ugashik Rivers as far as the weirs; and scale and 

 migrant collections were made at Kakwok, 80 miles up the Nushagak. 

 After the close of the commercial fishing season, a trip was made to 

 Wood Lake for the purpose of collecting young salmon and visiting 

 the spawning grounds. 



Several of the principal spawning grounds of Illiamna Lake were 

 inspected in the early part of August and in all cases there was a 

 marked deficiency in spawning fish. 



In addition to the scale collections made during the commercial 

 fishing season, arrangements Avere made to have Frank Waskey 

 collect scales from a series of 1,000 fish taken bv natives on both the 

 Nushagak and Wood Rivers. 



Cofyer River red-salmon investigations. — During the past year the 

 investigation of the red salmon of the Copper River has been con- 

 tinued by Seton H. Thompson, who devoted the greater part of the 

 time to making a comprehensive collection of scales from fish taken 

 by the commercial fishery and to studying the growth of the young 

 salmon in Gulkana River, one of the important spawning grounds of 

 the Copper Hiver. Scales were also collected from adult fish spawn- 

 ing in the various tributaries. Many of the scales appear to be 

 relatively easy to read, but others present irregularities that can not 

 be interpreted with certaint}^ until a very detailed study of the young 

 fish has been made. Since each tributary and its lakes presents 

 different environmental conditions, the study of the fresh-water, 

 growth of the scales is very complex. Five widely separated tribu- 

 taries of this great river system are known to be important spawning 

 grounds for the red salmon and many tributaries are still unexplored. 

 A definite program has been outlined, and this work will be continued. 



COLUMBIA EIVER SALMON 



As in previous years the Bureau of Fisheries has cooperated with 

 the Oregon Fish Commission in conducting salmon-marking experi- 

 ments. One new experiment with fingerlings of a landlocked spe- 

 cies, Oncorhynchus kennerlyi., was started. A previous experiment 

 with this species resulted in a few recoveries which seemed to indi- 

 cate that these landlocked fish could be induced to become sea-run 

 and contribute to the commercial fishery. The returns from the 

 first experiment were too few to be conclusive, and it seemed advis- 

 able to repeat the experiment. 



Very few returns of marked fish were anticipated in 1930 but these 

 few form a valuable part of the records obtained over a period of 

 years. 



ALASKA HERRING 



In December, 1930, a scientific report was submitted to the bureau 

 for publication by George A. Rounsefell Avho is in charge of the 

 herring investigation, showing the changes in abundance that have 



