NOTE Adams and Howard: Natural mortality of Sebastes mystmus 



159 



Gulch. At the beginning of the benthic stage in mid- 

 July, the ratio between the 1986 and 1987 Dark Gulch 

 annual density estimates is 1/23. After these two year 

 classes experience their respective mortality rates 

 (0.001-day- 1 for 1986, 0.005-day" 1 for 1987, Table 1) 

 from mid-July until the following April, the ratio 



between the year classes is reduced to 1/7.7. Although 

 there are no published values for variability in adult 

 blue rockfish year-class strength, the 1/7.7 ratio in 

 the example is consistent with ratios between small 

 and large adult year classes in other rockfish spe- 

 cies. For example, Hightower and Lenarz (1989) 



