FISHERY BULLETIN: VOL. 84, NO. 1 



Table 5. — Histological condition of jack mackerel collected near islands and banks 



off the coast of California. 



<fi 



<& 



* / & * 



^ J? 4? jr <* 



* w «P~ 



Daily percent 

 Starving 1 Dying 2 



'Number dying/d + starving/d 



Total 

 2 Number dying/d 



Total 



Table 6.- 



-Predicted condition of field-collected jack mackerel larvae determined 

 with the morphometric technique. 



2 Number starved/d 



Total 

 2 Unfed jack mackerel larvae die in 4 d. 



California and up to 1,000 mi off Oregon and Wash- 

 ington (reviewed by MacCall and Stauffer 1983). In 

 addition, jack mackerel have a protracted spawning 

 season which extends from March through 

 September. The bank and island habitat must be a 

 very small fraction of the total spawning habitat; 

 thus despite the higher survival in inshore areas, the 

 offshore zone may be the most important. In addi- 

 tion, better feeding conditions around islands may 

 be offset by a greater abundance of predators. 

 Whether the large concentration of starving larval 

 jack mackerel found offshore was an isolated case 

 or a general condition in offshore areas is unknown. 



Given that relative recruitment strength of jack 

 mackerel year classes varies greatly and is rarely 

 "average" (Fig. 17; MacCall and Stauffer 1983), the 

 daily mortality rate of about 45% found in this study 

 is not unrealistic Considering the relatively long life- 

 time (i.e, 30+ yr) and high fecundity of jack 

 mackerel, one can deduce that the overall mortality 

 may be very high. This study certainly indicates that 

 starvation at the onset of feeding may be an impor- 

 tant factor influencing recruitment variation in jack 

 mackerel. 



O'Connell's (1980) study of northern anchovy is the 

 only other study in which starvation in the sea has 



12 



