International Journal of Aquaculture, 2017, Vol.7, No.8, 57
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This study showed a positive role of use a specific light spectrum in coral growth, namely blue and red spectrum
with a specific growth rate of 0.210 to 0.380%/day. The results on control and with led are similar to the results
obtained on previous studies (Rocha et al., 2013), where the authors obtained a specific growth rate of 0.040 ±
0.010%/day, 0.038 ± 0.007%/day and 0.035 ± 0.009%/day when exposed fragments
Sarcophytum
spp. at an
intensity of 50, 80 and PAR 120 respectively, using a metal halide illumination (HQI) of 150 Watt.
As mentioned on results section, there was an influence of different illumination spectra in the growth rate of
Sarcophyton
spp. fragments. The utilization of light with specific wavelengths spectra, is to date poorly studded,
however the few studies existing are contradictory Wijgerde et al. (2014), when using illuminations of white, blue
and red spectrum found a negative response on the coral
Stylophorapistillata
, showed an negative response of
coral fragments exposed to red light and a positive response in blue light. However, Kinzie and Hunter (1987)
found no differences in
Montiporaverrucosa
response when fragments were exposed to different lighting, white
and blue. These different responses of different species, show the need to increase knowledge about specific
growing conditions ex situ for each species in order to guarantee a supply of cultivation conditions to guarantee
maximum profitability.
In the presented study there was no influence of the lighting spectrum in zooxanthellae density. However the
density obtained in the different treatments is in the order of magnitude between and. This data is in agreement
with the results obtained by Rocha, et al. (2013) that the exposed coral fragments
Sarcophytonglaucum
species for
60 days under different intensities of PAR (50, 80, 120) obtained zooxanthellae densities on the order of 107. In
contrast, Wijgerde et al. (2014) who obtained average values in the order of 106 when submitted coral
Stylophorapistillata
species for 6 weeks to PAR intensities of 128 and 256 in different LED lights (blue LED, red
LED, blue LED mix and red and white lighting control T5), in these conditions the author found that a pair of the
different LED 128 does not affect the amount of zooxanthellae, but there influences using a PAR 256 to give over
zooxanthellae the blue LED lighting.
Also, it was found that the fragmented area of each of coral doesn’t differs in zooxanthellae density with
non-fragmented area of the same coral. This result indicates that there was a regeneration of the tissue after
healing since, after fragmentation and an expected to decrease of zooxanthellae in the affected area. Whereas the
zooxanthellae in all treatments were within acceptable values according to the literature and knowing the density
increases very zooxanthellae when present the optimal light conditions (Rocha et al. 2013c) this study showed that
the four types of lighting provided good conditions for the growth of zooxanthellae.
In this study, we also evaluated the effect on survival rate, growth, healing and zooxanthellae density of
Sarcophytumspp
fragments using LED lights with different spectrum (white, blue and red) comparatively to a
traditional white illumination T8. It is concluded from this study that fragments of this species of soft coral, have a
best response to when exposed to Red and Blue LED, moreover differences weren't observed between the use of
white LED and T8 Fluorescent light.
The LEDs used in this study have energy consumption of 3 watt and the white traditional lighting T8 a 72 watt.
Accordingly beyond the LED lights can increasing the growth of corals, they can do it with less energy cost. Thus,
knowing that energy costs are a major cost to consider in aquaculture a substantial reduction in energy costs of
lighting can be synonymous of economic viability of ex situ coral aquaculture.
In order to confirm the potential of aquaculture profitability ex situ coral through the use of LED lighting, more
studies are needed, including the extension of this study to other species of coral, as well as the study of the
combination of different LED spectrums, to optimize growth rates.
Although this study will contribute to increased knowledge and for the feasibility of soft corals aquaculture there
is still a long way to go, with many studies that can be done to optimize the growth of coral for ornamental and
biotechnological purposes.
