Rodgveller et al.: Age at maturity, skipped spawning, and fecundity of female Anoplopoma fimbria 
97 
Age (yr) 
Figure 5 
Logistic regression model fitted to the proportion of female sablefish (Anoplopoma 
fimbria) mature at age based on data from a survey conducted in winter (December 
2011) (all graphs), (A) on data from annual summer longline surveys conducted by 
the NOAA Alaska Fisheries Science Center in 1996-2012, (B) on the maturity-at-age 
data currently used in the Alaska sablefish stock assessment, and (C) on the mean 
maturity at age data collected from annual summer longline surveys (mean of annual 
estimates in panel A). Graph B provides a comparison of data collected in surveys con- 
ducted in summer with data collected in winter 2011. Fish that would skip spawning 
were classified as either mature or immature and were identified only in the winter. 
231) (t-test assuming unequal variance: P=0.001), indi- 
cating that, on average, younger fish have smaller ma- 
turing oocytes. The range in number of eggs per gram 
of sample weight was greater for younger fish than for 
older fish. 
The relationship between relative fecundity and age 
was not significant. Very little of the variation in fe- 
cundity was explained by age (coefficient of determina- 
tion [r 2 ]=0.02), and the regression was not significant 
(slope: -0.49, P=0.37; intercept=123). Relative fecun- 
dity ranged from 66 to 205 per gram. 
The GSI of fish that would spawn (mean=7.361, 95% 
lower confidence interval [LCI]=6.908, 95% upper con- 
fidence interval [UCI]=7.814) was much higher than 
the GSI of fish that would skip spawning (mean=1.064, 
95% LCI=0.936, 95% UCI=1.191) and of immature fish 
(mean=0.486, 95% LCI=0.471, 95% UCI=0.502). Fish 
that would skip spawning had a higher GSI than im- 
mature fish (there was no overlap of the 95% CIs), 
although there was some overlap in the raw data 
(skipped spawning range=0. 486-1. 659; immature 
range=0. 145-1. 110) 
Discussion 
We found that the logistic models that were fitted to 
the pooled age-at-maturity data collected during sum- 
mer longline surveys and to the data currently used in 
the stock assessment, also collected during the sum- 
mer, were similar to the maturity curve from the win- 
ter data, when fish that would skip spawning were 
