76 FISH AND GAME COMMISSION 



It is intended that these investigations will establish a basis of 

 estimating the relative success or failure of each year class two or 

 three years before it enters -the commercial catch. Such a knowledge, 

 which will be very valuable to the fisheries industry, it is reasonably 

 sure can be obtained through the determination of the relative abun- 

 dance from year to year of the very young sardines, or larvae, as 

 they are called. This relative abundance is to be established by the 

 employment of specially constructed plankton nets operated quantita- 

 tively at key stations throughout the sardine spawning and nursery 

 grounds. 



Because of the magnitude of the problem, the investigations of the 

 past years have been devoted to three major studies: (1) The deter- 

 mination of the spawning area, (2) denning the area of maximum 

 spawning, and (3) establishing the constancy of these two areas from 

 year to year. Related secondary problems, such as the development 

 of the eggs, also the food, drift and rate of growth of the larvae, were 

 carefully considered, and all were studied whenever material was 

 available. 



In the pursuit of these major problems, approximately 15,000 

 miles of station lines were run, covering an area of about 252,000 

 square miles of oeean. The region covered lies between Eureka on 

 the north and Cape San Lucas, Baja California, on the south. Between 

 Eureka and San Diego, the entire body of water out to 400 miles was 

 covered by station lines. In the remainder of the region visited, the 

 exploratory work was confined to the proximity of the coast. 



As a result of the intensive work of these past four years (1929 

 to 1932), it is felt that the three major problems, as stated, are now 

 generally understood. With the exception of a few details, 1933 will 

 mark the beginning of an actual count of the relative abundance of 

 sardine larvae, these data to be used in predicting the fluctuations in 

 abundance of commercial sizes. 



A bulletin covering these preliminary findings is now ready for 

 printing and should be issued during 1933. This publication covers 

 three main results : 



(1) Spawning region. The major spawning area is a compara- 

 tively small region approximately 200 miles in diameter. From the 

 United States-Mexican international boundary to Point Conception 

 and offshore to 200 miles are the bounds of this limited area. 



The California sardine ranges for 2000 miles up and down the 

 Pacific coast between southern Alaska and the Gulf of Lower Cali- 

 fornia. They have never been seen or known to occur further than 

 200 miles from land. The fact that the great bulk of these sardines 

 migrate each year to a centralized area for the purpose of spawning 

 is perhaps the most important discovery of this investigation. 



(2) Time of spawning. The sardine eggs are found in the open 

 ocean in small numbers during February. They steadily increase in 

 numbers until April and May when they occur in greatest abundance. 

 By August the spawn has about disappeared. 



(3) Drift of the larvae. The sardine eggs hatch in three days. 

 As small larvae they are completely helpless and subject to drift. As 

 a result of currents, the major portion of these larvae are set to the 



