344 U.S. BUREAU OF FISHERIES 



Records of the daily catches of a selected group of traps in Puget 

 Sound were collected and analyzed on the basis of the average catch 

 per trap per fishing day, thus providing a constant unit of fishing 

 gear and time. When these records were analyzed and compiled in 

 the form of an index of abundance, the index indicated a marked 

 drop in the abundance of the Puget Sound sockeyes from 1917 to 

 1932, inclusive. 



A detailed inspection of the daily fluctuations in abundance of the 

 sockeye salmon during each fishing season indicates that the middle 

 portion of the season, which, at one time provided a large part of 

 each season's catch, has suffered the greatest decline. This may be 

 very significant, since from previous studies of red or sockeye sal- 

 mon it appears that each tributary of a large river system such as 

 the Fraser, which provides practically all of the Puget Sound run, 

 may support a separate race or population of sockeye salmon each 

 of which has a definite time of migration into the stream. There- 

 fore, this decline of the middle portion of the run may indicate that 

 certain races are being more rapidly depleted than others and are 

 in need of protection. 



Scale samples were taken during the past fishing season. These 

 will be studied in a attempt to link scale characteristics to the sea- 

 sonal fluctuations in the run. If this can be accomplished, the de- 

 gree of racial differentiation during the season can be established, 

 and possibly some of the races identified in the commercial fishery 

 and their spawning grounds determined. 



Marked fish from the Birdsview, Wash., marking experiments of 

 1929, 1930, and 1931 were recovered from the commercial catch dur- 

 ing the past season. This experiment was carried on for the pur- 

 pose of determining the most favorable time for the liberation of 

 hatchery-reared sockeye salmon. 



PINK-SALMON INVESTIGATION 



The pink-salmon investigation in southeastern Alaska, under the 

 direction of Dr. Frederick A. Davidson, was continued during the 

 past year and included a cooperative project with the National Can- 

 ners Association of Seattle in addition to the regular program of 

 activities. 



One of the natural handicaps encountered in the pink-salmon fish- 

 ery is the rapid decrease in the quality of the salmon as they become 

 sexually mature. With the onset of sexual maturity the male pink 

 salmon develops an enormous hump on his back and a greatly elon- 

 gated grotesque head. The hump is composed mostly of cartilage 

 and is grown at the expense of the fatty and muscular tissue of the 

 back. The female pink salmon, on the other hand, changes very 

 little in body form with sexual maturity but owing to the heavy 

 drain imposed upon its stored energy, by the maturation of the eggs, 

 it likewise deteriorates in condition very rapidly. In fact as both 

 males and females become sexually mature their flesh becomes soft 

 and loses practically all of its fat content and red coloration. 



When the pink salmon migrate into the inside waters of south- 

 eastern Alaska, they practically cease feeding and depend upon their 

 stored energy for maintenance and growth during the remainder of 



