Rodgveiler et al.: Effects of maternal age and size on embryonic energy reserves and developmental timing of Sebastes maliger 
41 
increase in weight (20% of range 
in weights) the predicted increase 
in stage was 0.8, 1.1, or 1.4 stages. 
Age was log normal and there- 
fore the rate of change in stage 
between ages varied. From age 
5-10 years there was a predicted 
increase in stage of 1.0, 2.0, and 
2.4 stages; from age 20-25 there 
was an increase of 0.3, 0.6, and 0.7 
stages; and from age 40-45 there 
was an increase of 0.2, 0.4, or 0.8 
stages. 
None of the regressions of weight 
and weight-specific fecundity were 
significant (Table 2), indicating 
that reproductive potential does 
not increase faster with increasing 
size or age. 
Discussion 
Ours is one of a few studies to 
relate timing of parturition for 
rockfish with age and size. Other 
studies have found that size is 
related to timing of parturition 
only for some rockfish; however, 
few found a relationship with age. 
Sogard et al. (2008) found that 
fish size was related to parturi- 
tion date for three of five species 
of rockfish. In another study, larger 
dark-blotched rockfish (S. crameri) 
had reproductive events (e.g., mat- 
uration and vitellogenesis) earlier 
than smaller individuals (Nichol 
and Pikitch, 1994). There were 
not many indications of a relation- 
ship between parturition date and 
age) in the literature. Pacific ocean 
perch (S. alutus) did not show a 
trend in embryonic development 
stage by age or size (Hannah and 
Parker, 2007). Older black rockfish 
had earlier parturition dates than 
younger ones only in some years 
(Bobko and Berkeley, 2004). Partu- 
rition date was not related to age 
for any of the five species examined 
by Sogard et al. (2008). 
Differences in parturition tim- 
ing of spring-spawning rockfish, 
like quillback rockfish in Alaska, 
could be related to earlier fertil- 
ization in older, larger mothers 
who have more energy available 
to divert to reproduction (Larson, 
1991; Sogard et al., 2008). Small- 
