356 
Fishery Bulletin 114(3) 
male:female dimorphism was present in the chelae but 
not in CW (Pinho et ah, 2001). In contrast, allometric 
relationships for ChL and ChW in C. affinis from the 
Canary Islands were strongly positive (approximately 
1.3-1. 5) and were used in hierarchical cluster analysis 
to distinguish immature from mature individuals of 
both sexes (Fernandez-Vergaz et ah, 2000). Logistic re- 
gression of these crab indicated SM50 values of 129 mm 
CW for male C. affinis — a size that would be equivalent 
to 103 mm CL for red deepsea crab if converted with 
the regression of CL on SW for the latter (Fernandez- 
Vergaz et ah, 2000). 
Determination of sexual maturity on the basis of 
morphometries works well for crabs of the families Or- 
egonidae {Chionoecetes spp.) and Majidae. The spider 
crab (Maja hrachydactyla) shows a typical curvilinear 
relationship between CL and ChH that becomes linear 
upon log-transformation, and Corgos and Freire (2006) 
used discriminant analysis to separate immature and 
mature male clusters. Their data were fitted even bet- 
ter by a 3-stage growth model, which included an in- 
flection point between juveniles and adolescent males. 
Therefore, excluding one study on C. affinis, morpho- 
metric relationships have not proved useful for deter- 
mining sexual maturity in the genus Chaceon. 
Distribution by depth and temperature 
At our sampling sites, highest abundance of red deep- 
sea crab occurred at depths between 500 and 650 m, 
and few crab were captured at depths <400 m. Female 
red deepsea crab dominated catches taken at depths 
shallower than 600 m, and males were more prevalent 
at greater depths. Haefner et al. (1974) reported that 
the highest abundance occurred at depths between 265 
and 512 m, and they observed that females dominated 
trawl catches above 400 m in and near Norfolk Canyon 
but that males became dominant below 400 m. 
Our data show a slight but significant decline in size 
of crab with increasing depth — a drop that was much 
more apparent for females. This decline in size is con- 
sistent with other reports that indicate that juvenile 
red deepsea crab are more common at greater depths 
(Wahle et al., 2008). We also found that the proportion 
of males increased with depth. Off the Namibian coast, 
C. maritae (misidentified as C. quinquedens) show simi- 
lar depth ranges; females predominate above 400 m at 
temperatures of ~8°C and males are more abundant 
down to 900 m and 4°C (Beyers and Wilke, 1980; as 
cited by Melville-Smith, 1989). In contrast, Kilgour 
and Shirley (2008) caught red deepsea crab by traps 
at depths of 533 to 1950 m in the Gulf of Mexico but 
found no significant relationships between depth and 
crab size or sex. Pinho et al. (2001) caught C. affinis 
with traps around the Azores Islands and found that 
the highest abundance occurred at depths between 700 
and 900 m. In that study, size of both sexes decreased 
slightly with increasing depth, but the proportion of 
males declined with increasing depth, in contrast to 
our results. 
Despite differences in depth distribution observed 
for red deepsea crab in our surveys, the differences in 
temperature distribution by sex were minor, and much 
overlap occurred between males and females. Simi- 
larly, differences in bottom temperature between years 
were minor despite sampling in either January or July, 
and differences weighted by crab catch were even less. 
These data indicate that temperatures at the depths 
sampled do not show great annual variation, and red 
deepsea crab tend to stay within a narrow range of pre- 
ferred temperature. This information indicates that red 
deepsea crab recruit as juveniles to waters deeper than 
those sampled, move upslope during development, and 
become mature in the shallowest zones, after which 
they undergo an ontogenetic migration back to inter- 
mediate depths. 
Female maturity and ovigerity 
Our estimate of SM50 for female red deepsea crab (61.6 
mm CL) was calculated by nonlinear logistic regression; 
therefore, a point estimate was possible. Haefner (1977) 
estimated female maturity on the basis of the relation- 
ship of AW to CL for females classified as mature or im- 
mature by gonopore condition, and he determined that 
maturity occurred over a size range of 65-75 mm CL. 
Haefner (1977) calculated 2 separate regression equa- 
tions for females with mature or immature gonopores 
(total 71=251) for the relationship between AW and CL 
that had similar slopes but different intercepts. How- 
ever, the equation for immature females was influenced 
by 3 extremely small crab. Likewise, AW of C. affinis 
has been reported to change in intercept at maturity, 
between 95 and 105 mm CW (equivalent to 76-84 mm 
CL) (Fernandez-Vergaz et al., 2000). 
In contrast, covariance analysis of our data did not 
support the hypothesis that the 2 relationships were 
different, and there were no extreme outliers (total 
number of females analyzed=182). Abdomen morphom- 
etry indicated that C. affinis females become function- 
ally mature (i.e., capable of bearing eggs) before reach- 
ing physiological maturity (which is assessed on the 
basis of apparent ovarian stage) (Fernandez-Vergaz et 
al., 2000). Logistic regression indicated SM50 values of 
108 mm CW (equivalent to 86.6 mm CL) for abdominal 
maturity and 113.4 mm CW (91 mm CL) for gonopore 
maturity of crab in the Canary Islands (Fernandez- 
Vergaz et al., 2000), whereas the SM50 for female red 
deepsea crab in the Azores determined by gonopore 
condition was 83.1 mm CL (Pinho et al., 2001). 
The presence of eggs on <50% of female crabs is a 
strong indicator that reproduction occurs at biennial 
(or longer) intervals. Haefner (1977) examined female 
red deepsea crab from the Norfolk Canyon, and report- 
ed that only 25.5% of females >71 mm CL were oviger- 
ous in January 1976. He also reported that abraded 
gonopores were present in 93.5% of female red deepsea 
crab >71 mm CL but not in any crab <70 mm CL. In 
the Azores, ovigerous C. affinis were found only in the 
fourth and first quarters of the year, with a maximum 
