In all experiments, arcsine transformations of the percentage survival were analyzed Ž
. through analysis of variance ANOVA followed by Duncan’s New Multiple Range Test
Ž .
Walpole, 1982; Gomez and Gomez, 1984 .
3. Results
3.1. Loading densities Immediately after a 6-h simulated transport, survival rates of megalopae were similar
at 100 and 150 ind l
y1
and both were significantly lower than survival at 50 ind l
y1
Ž .
Fig. 1 . The same trend was obtained for survival at 15 h post-transport.
Fig. 1. Survival of S. serrata megalopae at different loading densities immediately and 15 h after transport. Ž
. Bars with the same designated letter are not significantly different P 0.05 .
3.2. Loading densities, duration and shaking Three-way ANOVA of survival immediately following transport showed that there
was no significant interaction between density, shaking, and duration. Likewise, no significant two-way interaction between density and shaking or duration was detected.
Ž .
However, survival was significantly affected by loading density P - 0.001 and an
Ž .
interaction between condition and duration of transport P - 0.01 . Survival was
y1
Ž .
y1
significantly higher at a loading density of 50 ind l 86.7 2.4 than at 100 ind l
Ž .
79.7 2.1 , regardless of the duration. As to the effect of shaking and duration, megalopae transported with or without shaking for 3 or 6 h had similar survival as those
transported with shaking at 9 h. Megalopae that remained unshaken for 9 h had the Ž
. lowest survival compared to other treatments regardless of the loading density Table 1 .
A three-way ANOVA of survival at 15 h post-transport revealed a significant interaction between duration, condition of transport, and loading density. Hence, a
two-way ANOVA was conducted for each transport duration. At 3 and 6 h duration, there was a significant interaction between loading density and shaking. Megalopae
packed at 50 ind l
y1
without shaking had lower survival than those subjected to shaking Ž
.
y1
at 3 and 6 h transport time Table 1 . At a loading density of 100 ind l , survival of
megalopae subjected to shaking did not differ significantly from those that remained unshaken. At 9 h, megalopae subjected to shaking had higher survival than those that
Ž .
remained unshaken whatever loading density was used Table 1 . Initial ammonia and nitrite levels were 0.03 and 0.15 ppm, respectively, while
dissolved oxygen was 6.5 ppm prior to oxygenation of transport bags. Water quality after transport did not show any difference among treatments except in unshaken bags
Table 1 Ž .
Ž . Ž .
Survival of S. serrata megalopae A immediately and B 15 h after simulated transport lasting for 3, 6, Ž
y1
. Ž
. or 9 h at two densities 50 and 100 ind
and conditions shaken and unshaken A. Immediately after transport
Transport Shaken
Unshaken
U y1
y1
Ž . Ž
. Ž
. duration
h 50 and 100 ind
50 and 100 ind
a a
3 875
893
a a
6 893
843
a b
9 883
633 B. 15 h after transport
Ž . Transport duration h
Shaken Unshaken
y1 y1
y1 y1
50 ind 100 ind
50 ind 100 ind
UU a
b b
b
3 846
502 453
591
UU a
b b
b
6 952
581 572
672
y1 y1
50 and 100 ind 50 and 100 ind
UU a
b
9 515
393
U
Ž .
Means SE in this block with the same superscripts are not significantly different.
UU
Ž .
Means SE in the same row with the same superscripts are not significantly different.
Table 2 Physicochemical parameters of seawater immediately after the 3, 6, or 9 h simulated transport. Ranges were
based on levels from the three transport durations Physicochemical
Density
y1 y1
parameter 50 ind l
100 ind l Shaken
Unshaken Shaken
Unshaken pH
8.1–8.2 8.0–8.2
8.0–8.1 8.0–8.2
Ž .
NO -N ppm 0.03–0.04
0.04–0.09 0.03–0.04
0.05–0.10
2
Ž .
NH -N ppm 0.26–0.32
0.36–0.57 0.26–0.42
0.41–1.18
3
y1
Ž .
containing 100 ind l , where the ammonia level was up to 1.18 ppm Table 2 .
Ž .
Dissolved oxygen levels 22–24 ppm were supersaturated in all bags after transport. 3.3. Simulated transport at Õarious temperature leÕels
Water temperature in the bags varied up to 1.5 8C from the desired temperature
during the 6 h transport. Two-way ANOVA showed that density and temperature
Fig. 2. Survival of S. serrata megalopae at various temperature levels over 6 h simulated transport in shaken Ž
. condition. Bars with the same letter are not significantly different P 0.05 .
separately influenced survival of megalopae. There was no significant interaction between density and temperature. Survival of megalopae was significantly higher at 24
than at 28 8C. Survival at transport temperature of 208C was similar to those obtained at
Ž .
y1
the two other temperatures Fig. 2 . On the other hand, a stocking density of 50 ind l Ž
.
y1
Ž .
78.5 1.7 gave better survival than 100 ind l 74.9 0.6 at all temperatures.
4. Discussion
