337
(17.11)
(17.12)
Lee et al. (1994) estimated the instantaneous growth rate of cultured S� lessoniana
(temperature of 23.2 ± 0.6 °C) to be 3.9–5.3 BW·day
−1
for the entire life span and
8.2–12.0 BW·day
−1
for the first 100 days after hatching in closed water systems.
Forsythe et al. (2001) examined the effect of temperature on the growth of cultured
S� lessoniana in a closed water system. They estimated that squid grown at approximately 27 °C attained a size of 10 g in as little as 45 days at a sustained growth
rate of 12.2 % BW·day
−1
, while squid cultured at 20 °C required almost 100 days to
attain the same size at a rate of 5.7 % BW·day
−1
. Kanamaru and Itoh (1996) did not
find any difference in the growth of females and males with ML 45–160 mm. On the
other hand, Ueta (2000a) used the following equation to describe the relationship
between BW and ML for a natural population of S� lessoniana with ML 7–470 mm
in Japanese waters:
(17.13)
(17.14)
Survival of squid older than 30 days does not often change drastically, but intermittent death from unknown causes sometimes occurs in closed water systems. Between 70 and 140 days after hatching, only 1–2 of 25 squid die daily, and those
that die are always the smallest in the rearing population (Fig. 17.9; Sugimoto and
Ikeda 2013). In addition to the size variation that occurs at hatching, much greater
size variation occurs in culture tanks 2 months after hatching (Sugimoto and Ikeda
Squid 25 mm ML BW
398 ML
9734
2 481
<
=
=
,
.
(
.
)
.
0 000
0
r
2.680
Squid 25 mm ML, BW 0.000287 ML (
0.9914)
r
>
=
=
Female BW
183 ML
996
2 581
,
.
(
. )
.
=
=
0
0
r
2.562
Male, BW 0.186 ML (
0.997)
r
=
=
Fig. 17.9  Survivorship of
Sepioteuthis lessoniana in
culture conditions. Triangles
indicate survival rate;
diamonds indicate dead
individuals; circles and
bars indicate the average
and standard deviation of
dorsal mantle length (  ML).
(Sugimoto and Ikeda 2013)
17 Sepioteuthis lessoniana