THIRTY-FIRST BIENNIAL REPORT 119 



by N. B. Scofield, who discussed at the meeting the question of salmon 

 trolling. Several others who appeared before the committee spoke in 

 favor of either eliminating or curtailing salmon trolling. When the 

 committee learned that California has a similar committee, the secre- 

 tary was instructed to invite them to attend the Oregon meetings. A 

 meeting to discuss salmon questions is to be held at Astoria in the early 

 fall at which time the California committee will probably attend. Out 

 of all this activity and the desire on the part of Oregon to curb sea 

 trolling for salmon, it would seem that the closed season to trolling 

 now in effect in California will be adopted by the two states to the 

 north. California, however, needs a longer closed season than she 

 now has but, due to difficulties in the way of enforcement, is unable to 

 get it while the waters of Oregon are open. We have now reached the 

 stage where we should not rely on cutting down sea trolling alone, 

 especially if we have to wait for the states to the north of us, but we 

 should severely cut down the intensity of fishing on the Sacramento 

 River. 



SALMON INVESTIGATIONS 



In 1927 an investigation of the past and present status of the Sacra- 

 mento-San Joaquin salmon was started by G. H. Clark, a member of the 

 staff of this bureau, under the guidance of Dr. J. 0. Snyder of Stanford 

 University. The results of this investigation were published last year 

 as "Fish Bulletin No. 17." The bulletin is in three parts. Part I is 

 a historical and statistical review containing a history of the fishery, 

 salmon investigations, artificial propagation and legislation. There is 

 a statistical review of the salmon catch since the year 1874, and, in 

 conclusion, a section on the causes of depletion in which he says : 

 "Overfishing, one of the principal causes, should be curbed and more 

 stringent laws passed to control it, especially outside trolling." Part 

 II of the bulletin is a survey of the spawning grounds, in which is 

 given in detail the conditions on the main streams and tributaries of 

 the Sacramento-San Joaquin river systems, with their obstructions, 

 fish ladders and screens, the time of the salmon runs and the abundance 

 of salmon in each. He estimates that there are now 510 linear miles of 

 spawning beds suitable and available for spawning and that previous 

 to any obstructions in the streams there were at least 6000 linear miles 

 of stream bed suitable for spawning. At least 80 per cent of the 

 spawning grounds have been cut off by obstructions. Part III of the 

 bulletin deals with the life history of the salmon. See also "Shad, 

 Striped Bass and Salmon," by G. H. Clark, Fish Bulletin No. 20. 



For a number of years Dr. J. 0. Snyder of Stanford University has 

 been carrying on salmon investigations for this bureau. Some of the 

 outstanding results of his investigations have appeared frequently as 

 special articles in California Fish and Game. The following is a brief 

 summary of results and work in progress as submitted by Dr. Snyder : 



The usual statistical and observational work has been carried on. The 

 marking experiments with king salmon, which were begun some time ago, 

 have come to a close and details are now ready for publication. Evidences of 

 depletion are everywhere present, and in some eases the situation appears 

 serious. 



The outstanding features of the marking experiments may be summarized 

 as follows : 



Hatchery produced, pond reared fish, after liberation, migrate to sea, grow, 

 mature, and return to breed as do native fish. 



