DISTRIBUTION OF EGGS AND LARVAE OF JACK MACKEREL 



255 



Table 5. — Estimated number (in billions) of jack mackerel eggs in survey area, 1954 

 [Cruise numbers in parentheses. No eggs taken during cruise 5412) 



' Hundredths of a percent are used so that trace amounts of spawTiing may be indicated (see p. 252). 



Spawning in 1951 began in Fobruarv. About 

 7 percent of the total number of eggs for the 

 season were spawned during this month. Spawn- 

 ing rose to a peak of more than 30 percent of the 

 total in March, and then gradually declined until 

 June, when an increase occurred. Spawning de- 

 creased thereafter, being negligible in September. 

 Spawning during February and March was 

 centered about 150 miles offshore in region 2. 

 During the ne.xt 2 months spawning was more 

 general and no compact center was observed. 

 Spawning had reached its widest distribution (most 

 of the eggs being taken between lines 00 and 120) 

 ill April and May, and tiie center liud moved 



inshore. During June and -July tlie center was 

 dispersed and offshore. 



Spawning in 1952 began in January, when less 

 than 1 percent of the total number of eggs were 

 spawned, and rose to a peak of about 30 percent 

 in May. It then declined to less tlian 1 percent 

 in September and ceased altogether by October. 

 The center of spawning was about 120 miles 

 farther south during February and March than 

 during the same period of 1951. Once again it 

 was in the intermediate area. During April and 

 May, spawning became heavier in region 3 and 

 there was a strong inshore movement. During 

 tlie final 2 months the spawners were grouped to 



