International Journal of Aquaculture, 2017, Vol.7, No.8, 57
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with protein skimmer, biological filter, UV sterilizer, sand filter and submerged pump that provided of 300 L/h
flow into each PVC tank. The system operates with natural seawater, filtered by UV sterilizer (V2ecton 18, TMC)
and filter with 5 μm.
Each PVC tank was illuminated from above with same Photosynthetic Active Radiation (PAR) of 70 ± 10 μmol
quantam
−2
s
−1
, however light spectrum differs between different light sources, T8 white lamp (4* T8 15 Watt)
(control group), white Led (3* 1 watt), red Led (3* 1 watt) and blue Led (3* 1 watt). The maintenance and
monitoring of the culture system was identical to the described above for mother colonies.
2.3 Coral fragments growth
To determine the growth of coral fragments, buoyant weight measurements (Davies, 1989) were made at the start
(day 0) and the end of the experiment (day 30). Each coral fragment was measured 5 times to guarantee
reproducibility. The influence of the light spectrum was evaluated through the estimate of the specific growth rate
(SGR% weight gain day
-1
)
1
.
1
SGR = 100 (In Wt - In Wi)/t
(De Oliveira et al., 2012) Where Wi and Wt, are the initial and final coral weights and the t is time in days.
2.4 Zooxanthellae density
Zooxanthellae density was measured in the mother colonies and on the fragments at the end of the experiment. At
each fragment, the zooxanthellae density was evaluated at two areas: fragmented and non-fragmented side. To
determine zooxanthellae density a sample of coral tissue was removed with a scalpel and homogenized on falcon
tubes containing 50 mL of filtred (0.2 μm) seawater. The solution was diluted to a known volume and
homogenized before a zooxanthellae counting in a Burker chamber. To guarantee reproducibility, 3 samples of
each homogenized was counting.
2.5 Statistical analysis
Growth performance parameters and zooxanthellae density are reported as means ± standard error of mean
(SEM).
All data were checked for normality and homoscedasticity. A one-way analysis of variance (ANOVA) was used
to determine significant differences of the different light spectra on coral growth and zooxanthellae density (Zar,
2009). Post hoc pairwise analysis (Tukey test) was conducted to determine significant differences among
experimental combinations. When assumptions (that is, normality and homoscedasticity) were not met,
Kruskal–Wallis, followed by Games-Howell test was employed as appropriate (Games and Howell, 1976; Kirk,
1982). For all statistical tests, the significance level was set at p≤0.05. All calculations were performed with IBM
SPSS Statistics 22.
3 Results
During the experimental period the water quality was evaluated and maintained constant conditions with normal
parameters values for the good maintenance of this specie: OD > 8.0 mg/L, pH between 7.8 and 8.4 temperature
24 to 26ºC, salinity 32 to 35 total ammonia and nitrite below 0.5 mg/L, nitrate < 10 mg/L and phosphates < 0.5
mg/L.
3.1 Coral fragments growth and survival
At the beginning of the experiment the average net weight of fragments was 0.720 ± 0.06 g for control group (T8
with light), 0.782 ± 0.06 g for white led light, 0.742 ± 0.03 g for blue led light and 0.690 ± 0.07 g for red led light.
At the end of the period (30 days), the SGR (Figure 1) varied between 0.055 ± 0.09 %/day in control group and
0.091 ± 0.019%/day, 0.210 ± 0.031%/day and 0.380 ± 0.245%/day in, white, blue and red light, respectively. The
