348 
Fishery Bulletin 1 14(3) 
Table 2 
Mean temperatures (°C), with standard deviations (SD) and results of analysis 
of variance between years, from surveys of red deepsea crab {Chaecon quinque- 
dens) conducted in the Mid-Atlantic Bight in 2011, 2012, and 2013. Results are 
averaged across all trawl tows made at each site (Temps), weighted by numbers 
of crabs caught (Tempe), and for females with eggs (Tempg). Also shown are 
results of analysis of variance between years, including i^-value {F), probability 
(P), and degrees of freedom (df). 
Year and 
results of 
variance 
Tows 
Temps 
Tempc 
Tempe 
Jan 2011 
6 
6.9 (SD 1.5) 
6.41 (SD 0.96) 
6.05 (SD 0.76) 
Jan 2012 
12 
7.8 (SD 3.0) 
6.07 (SD 1.10) 
6.27 (SD 0.62) 
Jul 2013 
8 
8.0 (SD 2.6) 
6.71 (SD 1.11) 
7.68 (SD 0.72) 
Total 
26 
7.8 (SD 2.5) 
6.37 (SD 1.09) 
6.25 (SD 0.82) 
E 
0.361 
44.48 
26.08 
P 
0.701 
<0.001 
<0.001 
df 
2,23 
2,2813 
2,330 
Results 
Catch and density 
During cruises of NOAA research vessels in 2011, 
2012, and 2013, 26 deepwater tows were completed 
for research of red deepsea crab (Table 1). One site 
(BIG) was sampled only in 2012, whereas others were 
omitted in some years (e.g., BWC in 2011), and not all 
depths were sampled each year because of time con- 
straints. Mean bottom temperatures at all sampled 
stations did not differ significantly between years de- 
spite sampling in January of 2011 and 2012 and in 
July of 2013 (Table 2). Temperatures weighted by 
number of crab captured differed significantly among 
years, but the greatest differ- 
ence was <0.7°C. Temperatures 
at which ovigerous females oc- 
curred also differed significantly 
among years and temperatures 
were warmer in July 2013 than 
in January of either 2011 or 2012. 
Although differences between sta- 
tions were minimal, crab concen- 
trated at specific depths in each 
season, and, as a result, crab- 
weighted temperatures showed 
greater differences because of 
changes in crab distribution. 
During the 3 cruises combined, 
5594 male and 10,627 female 
crab were captured for a total of 
16,221 crab, of which 2815 crab 
(17.4%) were measured, including 
1191 males (21.3% of males) and 
1624 females (15.3% of females). 
Highest mean densities occurred 
in the middle slope depth stra- 
tum (450-700 m; Table 3) for both males (131 indi- 
viduals/ha) and females (300 individuals/ha), but dif- 
ferences between sites were not significant (Table 3). 
However, mean densities of male crab were signifi- 
cantly greater in 2011 than in 2012 or 2013; a simi- 
lar but nonsignificant decline occurred for females. 
This difference remained even after removal of site 
BIG (only sampled in 2012) and was mostly due to 
samples at sites Hud and Nor. Estimates of biomass 
density were calculated with mean weights from 13 
subsampled tows and ranged from 0 to 241 kg/ha, 
with a mean of 49.7 kg/ha (SD 69.6). Biomass aver- 
aged across years was lowest at site BIG (14.7 kg/ha 
[SD 13.1]) and highest at site BWG (77.4 kg/ha [SD 
106.4]) (Table 4). 
Table 3 
Mean density (individuals/ha), with standard deviations (SDs), of red deepsea crab {Chaecon quinquedens) averaged across 
depth strata, years, and sites sampled in the Mid-Atlantic Bight during 2011-2013. Analysis of variance results include 
E-value (E), probability (E), and degrees of freedom (df). Superscript letters indicate similar groups (within columns) where 
E<0.05. Sampling occurred at 3 depth strata, shallow (250-450 m), middle slope (450-700 m), and deep (700-850 m), at 4 
sites. Block Island Canyon (BIC), Hudson Canyon (Hud), Baltimore and Washington Canyons (BWC), and Norfolk Canyon 
(Nor). 
Stratum 
Male 
Female 
Year 
Male 
Female 
Site 
Male 
Female 
Shallow 
18* (SD 30.7) 
30* (SD 47.7) 
2011 
151“ (SD 114) 
271 (SD 214) 
BIC 
32 (SD 35.6) 
24 (SD 25.6) 
Middle 
131“ (SD 100) 
300“ (SD 263) 
2012 
48* (SD 57.9) 
101 (SD 229) 
BWC 
71 (SD 86.6) 
250 (SD 358) 
Deep 
55* (SD 29.0) 
19* (SD 6.6) 
2013 
37* (SD 47.6) 
73 (SD 147) 
Hud 
81 (SD 98.2) 
125 (SD 193) 
Nor 
55 (SD 61.4) 
96 (SD 95.9) 
Analysis of 
variance 
E 
2.559 
0.47 
7.263 
2.97 
0.319 
0.817 
P 
0.123 
0.5 
0.013 
0.09 
0.811 
0.498 
df 
2, 23 
2, 23 
1, 24 
1,24 
3, 22 
3, 22 
