NOTE Jones and Ugland: Reproduction of female Squcilus acanthus 
687 
11 
■ 1987, n=1 10 
0 1997, n=79 
11 14 17 20 23 26 29 
Mean value of age groups (years) 
Figure 3 
Percentage of mature fish in the different age groups 10-12, 13-15, 16-18,19-21, 
22-24, 25-27 and 28-30 years in 1987 and 1997. 
1997 sample also had a larger proportion of mature fish 
less than 15 years of age. 
No individual was mature under 76 cm, but all individu- 
als over 88 cm were mature, indicating that maturity occurs 
between 76 and 88 cm. The length at 50% maturity was 81 
cm in both 1987 and 1997. There may be a difference in the 
growth rate between the two years; fish from 1997 reached 
maturity earlier than fish from 1987. However, because of 
the small sample size and difficulty with age determina- 
tion, caution should be used to interpret this result. 
Fecundity 
In 1987 the number of ovarian eggs with a diameter over 
2 cm (indicating mature fish) varied between 5 and 14 
(mean=8.2, SD=2.2). In 1997 the range was 3-17 eggs 
(mean=8.9, SD=3). The relationship between egg number 
and adult length in the 1987 and 1997 samples was not 
significantly different. On average, the egg production 
increased by one egg per 4-cm adult length. 
The number of free-living embryos in 1987 varied from 
2 to 14 per female (mean=6.6, SD=2.7). In 1997, free- 
living embryos numbered between 3 and 15 (mean=7.5, 
SD=2.6). The increment of free-living embryos per adult 
length (Fig. 4) in the 1987 and 1997 sample was not sig- 
nificantly different. However, the level of the regression 
line was significantly higher in 1987 (P=0.04). On average, 
the females in 1987 carried 1.2 more free-living embryos. 
It should be emphasized that owing to the large variabil- 
ity, length could only explain 45% to 56% of the difference 
in the number of free-living embryos. 
Reproduction cycle 
Eggs on which the blastoderm was visible, were recog- 
nized as recently fertilized. This was part of the candle 
