592 
Fishery Bulletin 99(4) 
Table 2 
Male California halibut total length versus age (mostly whole otoliths, some sectioned) in southern California. 
TL (mm) 
Age (yr) 
Mean age 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
201-225 
2 
1 
2.3 
226-250 
2 
5 
2 
2.0 
251-275 
1 
20 
14 
2.4 
276-300 
1 
51 
59 
4 
1 
2.6 
301-325 
14 
33 
4 
2 
2.9 
326-350 
7 
21 
18 
5 
3.4 
351-375 
4 
32 
34 
17 
3 
3.8 
376-400 
11 
25 
16 
6 
1 
4.3 
401-425 
5 
10 
25 
8 
12 
2 
5.3 
426-450 
8 
15 
15 
11 
2 
5.7 
451-500 
6 
14 
26 
21 
6 
6 
6.3 
501-525 
1 
7 
14 
17 
5 
2 
6.5 
526-550 
1 
5 
9 
8 
4 
2 
7.5 
551-575 
2 
9 
9 
9 
3 
1 
7.2 
576-600 
1 
4 
7 
1 
3 
0 
1 
1 
7.6 
601-625 
1 
6 
5 
2 
3 
8.0 
626-650 
1 
4 
1 
2 
7.5 
651-675 
0.0 
676-700 
0.0 
701-725 
1 
1 
8.5 
Mean length 
259 
289 
319 
377 
417 
482 
506 
538 
552 
578 
577 
586 
Median length of distribution: 387 mm TL 
within-reader average percent error ranged from 4.7% to 
8.9%. 
In southern California, significant differences between 
males and females were found in comparisons of length 
distributions (Kolmogorov-Smirnov: D=0.42, P=0.0001). A 
higher proportion of males were smaller than females (Fig. 
4). The median length for males was 387 mm TL (range: 
210-707 mm TL); the median length for females was 544 
mm TL (range: 241-987 mm TL) (Tables 2, 3, and 6). Fe- 
males on average were significantly larger than males for 
ages 3 through 10 (Mann- Whitney tests, Table 6). 
Some differences in lengths were also found between 
males and females in central California. Most of the larger 
fish were females (Fig. 4). However, the length distributions 
of males and females in central California were not signifi- 
cantly different (Kolmogorov-Smirnov: D= 0. 14, P= 0. 12). The 
median length for males was 437 mm TL (range: 285-781 
mm TL); the median length for females was 444 mm TL 
(range: 262-1039 mm TL) (Tables 4, 5, and 7). Females on 
average were significantly larger than males for ages 3 and 
5 through 8 (Mann- Whitney tests, Table 7). 
In addition, comparisons were made between regions for 
each sex separately. In comparisons of mean length at ag- 
es, the males in central California on average were signifi- 
cantly larger than those in southern California for ages 
2 through 9, except age 8 (Mann- Whitney tests, Table 8). 
The females in central California on average were signifi- 
cantly larger than those in southern California for only 
ages 5, 7, and 8 (Mann-Whitney tests, Table 8). However, 
the median length of females in southern California (544 
mm) was greater than the median length for those in cen- 
tral California (444 mm). 
In southern California, age distributions were signifi- 
cantly different for males and females (Kolmogorov- 
Smirnov: D=0.18, P=0.0001). A higher proportion of fe- 
males were older fish compared with males. The primary 
age mode for females was age 6 and for males it was age 
3 (Fig. 5). In central California, age distributions were al- 
so different for males and females (Kolmogorov: D=0.20, 
P=0.008). Males had a higher percentage in the 6 to 8 year 
range and a lower percentage in the 3 to 5 year range com- 
pared with females (Fig. 5). In central California, the pri- 
mary mode for both males and females was age 3. With 
both regions combined, females were found up to age 13 
and males up to age 12. In comparisons of age distribu- 
tions between regions, we found that a higher proportion 
of halibut in southern California was older than halibut in 
central California (Fig. 5). 
Because differences in length-at-age were found be- 
tween sexes, von Bertalanffy growth parameters were cal- 
