International Journal of Aquaculture, 2017, Vol.7, No.8, 57
-
63
58
It is known that light is one of the main factors that influence coral well-being and that each species has specific
lighting requirements that influence its growth (Titlyanov and Titlyanova, 2002; Osinga et al., 2011). Light
variation is known to affect zooxanthellae density, photosynthetic pigment concentration and photosynthetic
efficiency, as well as changes in the density of zooxanthellae that can affect coral physiology and its response to
stress (Wang et al., 2008; Al-Hammady, 2013).
The process of reproduction by fragmentation is stressful for the coral and the maintenance of both the mother
colony and the fragments generated under adequate lighting conditions certainly has a fundamental role on the
post-fragmentation photophysiological processes and, therefore, on coral recovery (Rocha et al., 2013).
Although in the last years science has studied the effects of irradiance on coral and its algal symbionts, there is a
gap regarding the study of the effect of spectral quality on the maintenance and reproduction of corals in captivity
(Rocha et al., 2013).
It is well known each symbiotic coral have a specific spectral requisites, which is associated with
ecophysiological differences among coral and symbiont species and with selective absorption of visible light by
seawater (Iglesias-Prieto et al., 2004). The light released from a light-emitting diode has a specific
wavelength/colour and each LED light colour is limited to a very narrow range of wavelength. The fact that
certain wavelengths can be selected for means that useless wavelengths can be left out, increasing the growth and
health of corals and minimizing the production costs with increasing the feasibility of ex situ production of
ornamental corals.
The aim of the current study was to evaluate the effects of different light spectra, emitted by LEDs with different
spectrum of light red, blue and white on the survival, cicatrisation recover photobiology and growth performance
of one commercially important coral in the marine aquarium trade and bioprospecting on marine natural
biocompounds, the leather coral
Sarcophyton
spp.
2 Materials and Methods
2.1 Coral husbandry and fragmentation
Two mothers colonies of the leather coral
Sarcophyton
spp. with 10 and 12 cm diameter were kept in a life
support system and acclimatized during 3 weeks and were daily observed to detect any disease or parasite
infection The life support system consisted of a recirculating system of four PVC tank (25-L water volume 60 • 40
• 25 cm, L • W • H) connected to a 100 L sump with protein skimmer, biological filter, UV sterilizer and sand
filter. The recirculation was maintained with a 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. The
mother colonies were illuminated with T8 white lamp (4* T8 15 Watt) delivering a Photosynthetic Active
Radiation (PAR) of 70 ± 10 μmol quantam
−2
s
−1
at the level of the colonies with a 12 h light: 12 h dark
photoperiod. PAR value was measured with a Quantum Flux meter (ApogeeSQ-120, USA) with a submergible
sensor. The mother colonies were weekly fed with artemianauplii (10 indml
-1
). Salinity was maintained at 33 with
daily addition of freshwater purified by a reverse osmosis at a volume equal to the evaporated water. Water
quality, dissolved oxygen, temperature, salinity, pH, total ammonia, nitrite, nitrate and phosphate were measured
weekly.
After acclimation period, each mother colonies were fragmented using a scalper producing 10 similar sized
fragments per colony, with each one being individually attached with a rubber band to a labelled plastic coral
stand (TMC Coral Cradle ®, UK).
2.2 Experimental design
Five fragments (of the pool of twenty produced) were randomly distributed by one of the four PVC tanks of the
culture system similar to the life support system of mother colonies. The experimental system consisted on a
recirculating system of four PVC tank (25-L water volume 60 • 40 • 25 cm, L • W • H) connected to a 100 L sump
