BERRIEN: EGGS AND LARVAE OF SCOMBER 



Figure 7. — Distribution of Scomber scom- 

 brus larvae during May 1966. 





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X 



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KILOMETERS 



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Scomber scombrus. Relationship of 

 Temperature to Egg and Larva Occurrences 



Temperature dependence of spawning is 

 suggested by the parallel relationship of the sur- 

 face isotherms and the northeastward edge of the 

 egg abundance contours in May (Figure 5). This 

 temperature dependence is also implied by the 

 June cruise results, i.e., while shelf waters 

 warmed, with consequent northward and east- 

 ward displacement of surface isotherms, the dis- 

 tribution of eggs moved accordingly (Figure 6). 

 While the northern extent of the egg distribution 

 was defined only during the May cruise, the south- 

 ern extent was defined during both the May and 

 June cruises, falling within the 16.0°- to 16.9°C- 



temperature interval despite the northerly dis- 

 placement of temperatures between the two 

 cruises. Along wdth even higher water tempera- 

 tures prevailing during the August cruise, spawn- 

 ing had ceased entirely within the survey area by 

 that time. 



Sette (1943) related his egg catches to surface 

 temperature and reported a weighted mean of 

 10.9°C for all eggs taken in 1932, with 98% occur- 

 ring at 9.0°C to 13.5°C. During the May cruise of 

 our survey, similar surface temperatures were as- 

 sociated with the eggs. The weighted mean surface 

 temperatures for all eggs taken during May was 

 11.0°C, with 97% at 8.7°to 13.8°C and the temper- 

 ature associated with all eggs in May ranged from 

 6.3° to 16.9°C. 



107 



