CALIFORNIA PISH AND GAME 157 



The average size of the 1933 clams was 15 mm. as compared with 

 22 mm. for the 1931 clams at a comparable date. 



New laws proliibitino' digging or the possession of digging tools 

 on the beach at night and prohibiting the possession of digging tools 

 at any time in the closed area are expected to facilitate patrol work on 

 the beach. — Richard S. Croker, California State Fisheries Laboratory, 

 December 12, 1933. 



THE LIFE HISTORY OF THE BAY SMELT 



Three species of the Atherinidae, or silversides, family are taken 

 in California waters. The jack smelt plays the most important role in 

 the commercial fisheries of the entire State. Bay smelt, however, are 

 taken in important numbers in the San Francisco and Monterey regions 

 and small quantities occur in the southern California catches. The 

 grunion, the third of these three silversides, is renowned because of its 

 unusual habit of depositing the eggs at high tide line on the southern 

 California beaches. The life histories of the jack smelt and grunion 

 have been studied previously and published by the California Division 

 of Fish and Game.* Dr. Leonard P. Schultz now contributes the life 

 history of the bay smelt in a recent publication, "The age and growth 

 of Atherinops affinis oregonia Jordan and Snyder and of other sub- 

 species of bay smelt along the Pacific coast of the United States." f 

 Schultz 's work, which is revised in the following paragraphs, is of 

 special interest because of the problems which have arisen as a result 

 of the size limit placed on smelts by the last California State Legislature. 



Three subspecies of bay smelt are recognized as inhabiting the 

 mainland bays of the Pacific coast from Oregon to San Deigo, Cali- 

 fornia. Atherinops affinis oregonia ranges from Oregon to Humboldt 

 Bay, California. A. affinis affinis is found from San Francisco to Mon- 

 terey Bay and intergrades with A. affinis littoralis from Monterey to 

 Santa Barbara. The latter species occurs in bays as far south as San 

 Diego. 



Schultz 's paper covers in greatest detail the life history of A. a. 

 oregonia but also comprises studies of the life history of A. a. littoralis. 

 Calculations of the age and rate of growth are based on length frequen- 

 cies and scale readings. Scales proved satisfactory for age determina- 

 tion through the third year for the Oregon bay smelt. For the south- 

 ern California species, scales were not satisfactory because 15 per cent 

 of the fish failed to form an annulus in the first year and in other 

 instances the scale structures were so indistinct that in onlj^ 72 per cent 

 of the total could the annuli be identified. 



The approximate average standard length in millimeters at the 

 end of each year for the two species was found to be as follows : 



Age I 11 III IV V VI 



A. a. oregonia 



Male 98 185 21.5 230 240 255 



Female 100 190 220 240 260 280 



A. a. littoralis 



Both sexes 60 100 115 



* Clark, Frances N. 1925. The life history of Leuresthes tenuis, an atherine 

 fish with tide-controlled spawning habits. Fish Bull., no. 10, 51 pp. 



Clark, Frances N. 1929. The life history of the California jack smelt, Atherin- 

 opsis californiens'is. Fish Bull., no. 16, 22 jip- 



Thompson, William F., and Thompson, Julia B. 1919. The spawning of the 

 grunion {Leuresthes tenuis). Fish Bull., no. 3, 29 pp. 



t Univ. Washington, Publ. Biol., vol. 2, no. 3, pp. 45-102, 1933. 



