576 
Fishery Bulletin 99(4) 
Table 1 
Points used to construct the growth curve for early juvenile red king crab in Bristol Bay. Data originally presented 
Macintosh 4 are indicated as such; previously unpublished data are listed as “new.” 
in Stevens and 
Collection date 
Source 
Estimated age 
(days after settlement) 
n 
Size range 
(mm) 
Mean size 
±1 SD 
19 Jul-2 Aug 1985 
new 
11.5 
6 
2 
2.00 ±0.000 
10 Sep-19 Sep 1983 
new 
62 
134 
3. 0-6.0 
3.97 ±0.581 
21 Apr-6 Jun 1983 
new 
283.5 
10 
4. 0-6.0 
4.27 ±0.730 
26 May-1 Jun 1991 
Stevens and Macintosh 
319.5 
35 
4-14 
7.70 ±1.645 
5 Jun-16 Jun 1983 
new 
332 
13 
3. 0-7. 2 
5.19 ±0.982 
18 Jul-2 Aug 1985 
new 
376.5 
3 
8. 0-8. 4 
8.13 ±0.231 
10 Sep-19 Sep 1983 
new 
427 
45 
10-28 
14.63 ±3.447 
21 Apr-6 May 1983 
new 
648.5 
30 
10-32 
16.70 ±5.389 
26 May-1 Jun 1991 
Stevens and Macintosh 
684.5 
16 
18-29 
22.53 ±3.562 
5 Jun-16 Jun 1983 
new 
697 
25 
12-26 
17.05 ±4.102 
26 May-1 Jun 1991 
Stevens and Macintosh 
1049.5 
7 
34-47 
40.36 ±3.681 
tics of individual cohorts were resolved by using FiSAT. 
Donaldson et al. (1992) did not provide their original data; 
therefore we simply used the mean size-at-age values that 
they reported. Mean size-at-age values for each region 
were then fitted with seasonalized von Bertalanffy and 
Gompertz curves, as described previously. Age of crabs 
at Unalaska Island was calculated by using 1 July as 
the approximate settlement date, as suggested by Weber 
(1967); 14 June was used for Kodiak Island because Don- 
aldson et al. (1992) first collected benthic instars on this 
date. 
Mean size-at-age of late juvenile through early 
reproductive-age crabs 
Growth of late juvenile (-age 2+) through early repro- 
ductive-age crabs was examined by using data from the 
annual NMFS groundfish trawl survey from 1975 to 1999 
(please refer to Otto [1986] for a description of the annual 
trawl survey protocol and its spatial coverage). These 
data were used to construct annual length-frequency his- 
tograms for the Bristol Bay stock; length-frequency dis- 
tributions were examined to identify strong size modes, 
and the mean CL (±1 SD) associated with each mode was 
determined by using FiSAT. Two approaches were then 
employed to assign discrete mean size-at-age categories 
to the population, focusing on size modes with mean CL 
<100 mm. First, each strong year class that recruited to 
the population was identified, and the growth of individu- 
als in these year classes was determined by examination 
of progression of their length-frequency modes, from the 
first appearance of the year classes until they could no 
longer be resolved. Second, the mean CL associated with 
every strong size mode that appeared in all the annual 
length-frequency distributions, over the entire time series, 
was plotted to identify commonly occurring mean CLs that 
might represent consecutive size-at-age categories. 
Bottom temperature 
Area-averaged near-bottom temperature was calculated 
for each year from 1975 to 1999, to more fully interpret 
the growth rates observed in Bristol Bay region with 
respect to variation over time. The area-averaged near-bot- 
tom temperature represented the mean temperature over 
all trawl-survey stations located within the Bristol Bay 
region. Because the survey data were sometimes incom- 
plete and sampling stations were not located in precisely 
the same location each year, the temperature at the center 
of each trawl survey station was statistically interpolated 
with known values at surrounding points (i.e. “kriged”; 
see Cressie, 1993). Kriging was performed with the Surfer 
6.04 software package (Keckler, 1994) and a linear var- 
iogram model (Cressie, 1993). Area-averaged near-bottom 
temperatures for the Bristol Bay region were then cal- 
culated by using the kriged estimates obtained from the 
center of trawl survey stations. 
Results 
Early juvenile red king crab 
Resolution of age classes from length-frequency data col- 
lected in Bristol Bay in 1983, 1985, and 1991 provided 
1 1 estimates of mean size-at-age representing individuals 
ranging from approximately 12 to 1050 days after set- 
tlement (refer to Fig. 3, Table 1). Weber (1967) provided 
information resulting in 24 mean size-at-age estimates 
(Table 2) at Unalaska, for crabs estimated to be -86-964 
days after settlement. Donaldson et al. (1992) and Dew 
(1990) provided 22 estimates of mean size-at-age for 
crabs -0-720 days after settlement (Table 3) at Kodiak 
Island. Plots of early juvenile mean size-at-age are pre- 
sented in Figure 4 for Bristol Bay, Unalaska Island, and 
