674 



Fishery Bulletin 103(4) 



(Squalus acanthias), yellowtail rockfish, canary rock- 

 fish, redstripe rockfish, and Pacific cod (Gadus maero- 

 cephalus). All of these species were observed in more 

 than 50% of the selected tows. 



The cohabitants varied with depth. Tows conducted in 

 depths less than 200 m tended to include lingcod, dog- 

 fish, canary rockfish, and yellowtail rockfish, whereas 

 catches from greater than 200 m were dominated by 

 arrowtooth flounder, Pacific ocean perch, redstripe rock- 

 fish, and yellowmouth rockfish. Fishermen report that 

 silvergray rockfish are typically found over relatively 

 "hard" bottom, often in proximity to bottom that was 

 not trawlable because it was too rough. They are rarely 

 caught in midwater trawls. 



Aging and growth estimates 



The maximum ages observed in Canadian samples were 

 81 and 82 years for females and males, respectively. 

 The corresponding ages at the 99.9% percentiles were 

 76 and 77 years. 



Although we assumed that our aging methods for 

 silvergray rockfish provided unbiased estimates of age, 

 agreement between readers was poor. Agreement to ±1 



year was 60-80% for ages less than 20 years and then 

 declined with age. 



The standard errors of the growth parameter esti- 

 mates show that there is a significant, albeit modest, 

 difference in growth rates; females grow faster and 

 to a larger size (Table 3, Fig. 3). Maximum observed 

 length was 73 and 70 cm for females and males, respec- 

 tively. We estimated the length-weight relationship for 

 females and males separately and combined from 476 

 total specimens (Table 3, Fig. 3). The ratio of the mid- 

 point lengths for males and females was 97.2 (Table 4), 

 indicating little sexual dimorphism. 



Maturation cycle 



The field maturity observations were congruent for 

 females and males (Fig. 4). Testes began developing (stage 

 2) in September and October and were large and swollen 

 by November and December (stage 4) (Fig. 4). January 

 and March testes were in the late stages of mating (stage 

 6), whereas from April through August testes appeared 

 to be in a resting phase for males (stage 7). The few 

 observations of large swollen testes with running sperm 

 (stage 5) occurred from October through February. The 



