The Wrangell sentinel., 1933-07-14
By FREDERICK A. DAVIDSON
 U. s. Bureau of Fisheries

The number of salmon that com pose the pink-salmon runs in south eastern Alaska is never the same from year to year At times there is an abrupt change in the size of the runs from one year to another and again the change is more grad ual extending over a number of years. It is not great stretch of was the case even before whitemen came into this country. The fluc- tuation in the size of the runs then, being due for the most part to the natural causes that influenced their survival from year to year. Such would not be an unusual thing, for the elements that go to make up nature as a whole are continuously changing from time to time. In fact istics of all nature is the contin- uous change that takes place in it both on the land and in the sea.
 With the introduction of white man into this country and the sub sequent development of the commer- cial fisheries there has come an other and by far more effective cause which has contributed to the variability in the size of the pink 1Y1,r hn intensity of the commercial fishery that is imposed upon the pink-sal- mon runs as they migrate from the sea.
 Protection of Salmon Runs
 Since in nature only like tends to beget like, it is necessary to pro vide for an adequate escapement of pink salmon to the spawning grounds each season if future runs Jf pink salmon are expected to ap- bear. In view of this fact the Blu reau of Fisheries is endeavoring to regulate the intensity of the com mercial fishery so as to provide for an adequate escapement of pink sal mon to the spawning grounds each season. However, before there could be any assurance that the protec- tion of the salmon runs in any given stream would provide for future runs in that stream, it was necessary to know first, the extent to which the pink salmon return to spawn in the streams from which they came and second, the age at which they mature in the ocean and return to spawn. These two questions concerning the life his tory of the pink salmon have no doubt arisen at some time in the mind of everyone interested in the pink-salmon fishery. The Bureau of Fisheries has always recognized their importance and in the sum- mer of 1929 began a study of the life history of the pink salmon in southeastern Alaska with the aim of finding facts upon which a satis- factory answer to each of these questions could be based.
 Intensive Study
 Beginning with the summer of 1929 an intensive study has been made of the habits and character istics of the pink salmon in two in ofvia namely Snake Creek at Olive Cove and Anan Creek in Bradfield Ca nal. A temporary field laboratory has been constructed at Olive Cove where most of the biological work is carried on. Frequent visits are made to Anan Creek during the summer at which time number of pink salmon are removed from the stream and taken to Olive Cove for study. In this way many inter esting facts have been secured con- corning the habits and character istics of the pink salmon composing the runs in these streams.
 Do Pink Salmon Return to Their
 Parent Streams to Spawn?
 In studying the life histories of the sockeye and king salmon 1t was found that their homing instinct and age of maturity could be de- termined by an experiment. which included more or less simple op- eration upon the young salmon. This operation consisted of marking the young salmon by removing two of their fins at the time they were migrating to the sea. The young