62 
Fishery Bulletin 1 13(1) 
Table 3 
Sex ratios (maleifemale) of the hooded slipper lobster (Scyllarides decep- 
tor ) by size classes (total length [TL]) caught by double-trawler and pot- 
and-trap fleets off southeastern Brazil from May 2006 through April 2007. 
Significance codes based on chi-square test (x 2 ): ns=P>0.05; * P<0.05; ** 
PcO.Ol; and *** P<0.001. 
Size classes 
(cm TL) 
Number of specimens 
Sex ratio 
(M:F) 
p (y2) 
M 
F 
Total 
11-12 
1 
0 
1 
_ 
12-13 
0 
0 
0 
- 
- 
13-14 
2 
0 
2 
- 
- 
14-15 
5 
0 
5 
- 
- 
15-16 
12 
7 
19 
01:00.6 
0.25 ns 
16-17 
14 
14 
28 
01:01.0 
1.00 ns 
17-18 
20 
19 
39 
01:01.0 
0.87 ns 
18-19 
37 
14 
51 
01:00.4 
0.0013** 
19-20 
53 
26 
79 
01:00.5 
0.0024** 
20-21 
71 
33 
104 
01:00.5 
0.0002*** 
21-22 
62 
58 
120 
01:00.9 
0.53 ns 
22-23 
80 
46 
126 
01:00.6 
0.0025** 
23-24 
59 
52 
111 
01:00.9 
0.51 ns 
24-25 
41 
71 
112 
01:01.7 
0.0046* 
25-26 
18 
53 
71 
01:02.9 
0.0327* 
26-27 
12 
42 
54 
01:03.5 
0.0446* 
27-28 
11 
25 
36 
01:02.3 
0.0196* 
28-29 
7 
16 
23 
01:02.3 
0.0406* 
29-30 
5 
11 
16 
01:02.2 
0.13 ns 
30-31 
3 
10 
13 
01:03.3 
0.0522 ns 
31-32 
2 
7 
9 
- 
- 
32-33 
1 
3 
4 
- 
- 
33-34 
0 
3 
3 
- 
- 
34-35 
0 
1 
1 
- 
- 
35-36 
0 
2 
2 
- 
future interconversion between size variables, particu- 
larly measures of the abdomen (LA and AW) and indi- 
vidual body size (TL or CL). Currently, in Brazil, some 
boats have begun landing only the abdomen of lobsters 
(“headless” lobsters) — a trend that will hamper the use 
of CL for monitoring this resource in the future. Total 
length is measured routinely and is easier for fisher- 
men to understand compared with the other measure- 
ments of size used in this study (Sparre and Venema, 
1998; Chubb, 2000 ). 
Values of L 50 were smaller in species of the gen- 
era Ibacus (e.g., butterfly fan lobster) and Thenus (e.g., 
flathead lobster and T. indicus), with a species mean 
of 19.1 cm TL (SD 6.1) (Stewart et al., 1997; Courtney 
et ah, 2001 ), compared with L 50 values for species of 
the genus Scyllarides (e.g., blunt slipper lobster, Gala- 
pagos slipper lobster, and hooded slipper lobster), with 
a species mean of 25.0 cm TL (SD 5.6) (Demartini et 
al., 2005; Hearn and Toral-Granda, 2007; Oliveira et 
ah, 2008). Oliveira et al. (2008) estimated that the L 50 
for female hooded slipper lobster was 25.1 cm TL — a 
finding that is very similar to a result of our study 
(L5 o= 25.3 cm TL). 
Oliveira et al. (2008) noted that copulation in the 
hooded slipper lobster occurs immediately after female 
molting — an aspect of the reproductive biology of this 
species that could not be assessed in this study be- 
cause of the absence of molting or recently molted spec- 
imens. The absence of molting specimens in landings 
is most likely related to their reduced movement and 
the absence of feeding behavior at this stage (Lavalli 
and Spanier, 2007). These behaviors would preclude a 
molting lobster from entering a trap; therefore, fishery 
samples would not provide accurate copulation data. 
This bias was not present in a study by Oliveira et 
al. (2008), who used data from monthly lobster popu- 
lation surveys conducted during diving expeditions at 
Santa Catarina Island (in southern Brazil), in June at 
the beginning of the molting and copulation season. 
Spanier et al. (1988) observed that the Mediterranean 
slipper lobster begins these biological processes during 
the same month in the southeastern Mediterranean, 
