74 
Fishery Bulletin 1 14(1) 
Table 2 
Results of a principal component analysis of embryo 
morphometries of golden king crab (Lithodes aequispi- 
nus ). Percent variation and cumulative variation repre- 
sent the percentage of variance in the data explained 
by each principal component (PC) and the cumulative 
variance explained. Max= 
maximum; min: 
^minimum. 
Cumulative 
PC Eigenvalues 
Variation (%) 
variation (%) 
1 9.160 
83.3 
83.3 
2 1.040 
9.5 
92.8 
3 0.521 
4.7 
97.5 
4 0.216 
2.0 
99.5 
5 0.024 
0.2 
99.7 
6 0.018 
0.2 
99.8 
7 0.015 
0.1 
100 
8 0.003 
0 
100 
9 0.000 
0 
100 
10 0.000 
0 
100 
11 0.000 
0 
100 
Eigenvectors 
Measurement 
PCI 
PC 2 
Egg area 
-0.301 
-0.385 
Egg max diameter 
-0.217 
-0.614 
Egg min diameter 
-0.278 
-0.098 
Egg mean diameter 
-0.301 
-0.377 
Embryo area 
-0.324 
0.072 
Yolk area 
0.277 
-0.449 
Percent area of yolk 
0.324 
-0.122 
Eye area 
-0.324 
0.124 
Eye max diameter 
-0.321 
0.154 
Eye min diameter 
-0.314 
0.182 
Eye mean diameter 
-0.319 
0.172 
need a greater energy reserve at hatching than the en- 
ergy reserve of feeding larvae to ensure that they can 
develop to the first crab stage. 
The developmental time between extrusion and 
hatching (brooding time) and the duration of hatch- 
ing in this study both differ from previous reported 
values. Paul and Paul (2001) reported an average 
brooding time of 362 days (2269 degree-days [num- 
ber of days multiplied by the average temperature in 
degrees Celsius]) and an average hatching duration 
of 34 days (202 degree-days), whereas we observed 
an average brooding time of 436 days (-1526 degree- 
days) and an average hatch duration of 26 days (-91 
degree-days). 
This dissimilarity between studies may have re- 
sulted from the crabs in each study having come from 
different locations: Prince William Sound (Paul and 
Paul, 2001) and the Aleutian Islands (in this study). 
However, it is more likely due to the differences in 
holding temperatures. Paul and Paul (2001) held crab 
at the ambient temperatures found at a depth of 75 
m in Prince William Sound, 3.5-9.5°C, a range 1-4°C 
higher than the range of temperatures of the deeper 
waters in Prince William Sound where the golden king 
crab occur. We held the crab at a constant tempera- 
ture between 3°C and 4°C — a range that is probably 
more reflective of their natural environment. Along 
the Aleutian Islands, most mature females are distrib- 
uted at depths between about 300 and 500 m (Blau 
et al., 1996) where temperatures vary from about 3.5 
to 4.5 throughout the year (Stabeno et al., 2005). The 
increase in the number of degree-days necessary for 
development with increasing temperature also occurs 
in the blue king crab (Stevens et al., 2008) and snow 
crab (Webb et al., 2007). 
Morphometric analysis of golden king crab embry- 
os failed to provide a quantitative method for staging 
larvae. Stevens (2006) successfully used multivariate 
statistical techniques to identify stages in blue king 
crab and indicated that analyses could be used to bet- 
ter compare embryogenesis over a diverse range of 
crustacean species. Using similar techniques, we were 
not able to distinguish among the first 5 stages, which 
represent about 160 days or a third of the develop- 
mental time for embryos. These stages are difficult to 
distinguish morphometrically because the embryo and 
eyes are not yet measurable. This technique worked for 
the blue king crab because eggs decreased steadily in 
size during these stages (Stevens, 2006), but it cannot 
work for the golden king crab because the egg size in 
this species remained constant for about the first 250 
days of development in our study. On the other hand, 
the MT model (Long, 2016) provided an excellent fit to 
the data for stage transitions, explaining 99% of the 
variation in the data. These data provide quantitative 
estimates of the average duration of each embryonic 
stage and will serve as a baseline for studies of embryo 
development in the golden king crab. 
Climate change, that is, changes in temperature 
(Webb et al., 2007; Stevens et al., 2008), and ocean 
acidification (Long et al., 2013a; Long et al., 2013b) 
can have substantial effects on the early life histories 
of cold-water crabs. This study provides a baseline for 
future studies that examine either variability in em- 
bryo development times among different populations 
of the golden king crab or the effect of environmental 
variables on embryo development. Future studies on 
the reproductive biology of the golden king crab should 
determine whether primiparous and multiparous crabs 
differ in their reproductive cycles (e.g., Moriyasu and 
Lanteigne, 1998; Swiney, 2008; Swiney and Long, 2015) 
and what drives the high variability in the time be- 
tween the end of hatching and the time of mating in 
the golden king crab (Paul and Paul, 2001). 
Acknowledgments 
We thank the observers in fishery observer program of 
Alaska Department of Fish and Game and the captains 
and crews of fishing vessels from which the golden king 
