FISHERY BULLETIN VOL. 77, NO. 1 



1953 n PZ I 



I 1 PZ 2,3 



n z 1,2 



JFMA MJ J A S N D 

 MONTHS 



FIGUREV.— Isotherms of 10° and 15'C and occurrence of larvaeof 

 Sergestes stmdis at CalCOFI Stn. 90,37. 1951-54, off southern 

 California at 0-140 m. Shadow indicates zones where tempera- 

 tures exceed the average 10°- 15°C range of 1 950-55, No samplmg 

 indicated by ns. PZ, protozoeal stages; Z, zoeal stages. 



at lO^C, and 3) mortality increased greatly in 

 temperatures beyond 10°-15°C. We do not know 

 the depth where spawning and hatching of S. 

 similis take place in the natural habitat. How- 

 ever, the laboratory observations, coupled with 

 biological information on the other species of 

 sergestids and euphausiids (Omori et al.^), indi- 

 cate that the eggs of S. similis are shed in shallow 

 water at night when ovigerous females rise up- 

 wards. Adult S. similis seldom occur above the 

 50-m level at night where the temperature is usu- 

 ally >13°Coffsouthern California. Assuming that 



AUG 19, 1976 

 UNSEXEDr-, FEMALES 



oiJ r^., , ^n^ 



.IPJ 



CO 



< 



UJ 

 N 



X 



o 

 < 



tr 



UJ 



m 



3 



10- 



MALES 



:^ 



10 12 14 6 8 10 12 



10- 



10- 



CO 



< 



_1 

 o 



N 

 CO 



< 

 LlI 



10- 



2 



cr 



3 10- 



APR 12,1972 

 FEMALES 



jzO. 



JUNE 21,1953 



n 



-fl 



JULY 29, 1973 



-n^ 1 ^ l ^p 



AUG 24,1954 



Ff 



^PP^ i 



22„, OCT 28,1972 



'\\ 



10- 



I \ r 

 NOV 8 , 1975 



MALES 



&^ 



-f=^ 



^ 



-) — t — I — I — r 



10 12  14 16 8 10 12 



CARAPACE LENGTH (mm) 



'Omori, M., M. Mutch, and M, Kaetsu, 1974, Prediction of 

 Sergia lucens fishery in 1974/75 season. |In Jpn.l Unpubl. 

 manuscr., 5 p., distributed at the annual meeting of the 

 "Sakura-ebi" Fishing Unions. Shizuoka Prefecture. Japan. 



Figure 8. — Length-frequency histograms of Sergesles simitts 

 collected with a 6-ft IKMT ( Ai and a lO-ft IKMT (B) off southern 

 California. The samples were arranged m monthly order regard- 

 less of the year of .sampling. Lines trace development of sig- 

 nificant cohorts. 



192 



