PROGRESS IN BIOLOGICAL INQUIRIES, 19 3 



589 



In February of 1930, 36,000 pink-salmon fry were marked at the 

 Duckabush hatchery on Hoods Canal, Washington. The marking 

 was accomplished by means of clipping their dorsal and adipose 

 fins. This is the first time that the marking of pink-salmon fry has 

 been accomplished. The runs in Duckabush River and neighboring 

 streams of Hoods Canal will be carefully examined in the fall of 

 1931 for adult salmon bearing the marks. The Hoods Canal region 

 is unique in that an examination of its many streams will provide a 

 means of determining the degree of homing instinct of the pink 

 salmon, that is, whether they return only to the stream in which they 

 were hatched or whether they return to the streams of a general 

 region. Preparations were made to mark pink-salmon fry in Snake 

 Creek at Olive Cove, Alaska, in the spring of 1931. 



Figure 5.- 



-Shack used as a laboratory for pink salmon investigations at Olive Cove, 

 Alaska 



The marking experiments in Alaska will be supplemented b}^ a 

 racial analysis of the pink salmon in the various streams throughout 

 the terrij^ory in which the fry are marked. During the summer of 

 1930 weekly samples were taken of the pink salmon running into 

 Snake Creek at Olive Cove and into Anan Creek in Bradfield Canal. 



The racial characteristics of the pink salmon composing these sam- 

 ples were analyzed biometrically for the purpose of determining: 



(1) Differences in the racial characteristics of the salmon enter- 

 ing a given stream at diiferent times during the run. This has an 

 important bearing on the method of sampling the fish population in 

 a stream. For example, if the population is homogeneous with re- 

 spect to racial characteristics throughout the run, then a representa- 

 tive sample may be secured at any time during the run. However, 

 if the population is not homogeneous throughout the run, then 

 samples must be taken at regular intervals in order to secure a repre- 

 sentative sample of the population. 



(2) Differences in the racial characteristics of the pink-salmon 

 population in Snake Creek and in Anan Creek. 



