International Journal of Marine Science, 2024, Vol.14, No.5, 321-331 http://www.aquapublisher.com/index.php/ijms 329 fragments, with average 6~10 cm in length (Figure 6). Coral nurseries were deployed at 1.4 m~2 m (⁓2) and 4.6 m~5.1 m (⁓5) (depending on the tide level). The nursery was designed to do not exceed the natural height (about 40 cm) of natural coral rocks in the area. Tables-based and rope-based nurseries were located at approximately 4 m distance from each other. Figure 6 Scheme of the experimental design The coral fragments utilized in the study were Acropora aspera (n=60), Acropora muricata (n=60) and Montipora digitata (n=60). Coral fragments used for the project were exclusively represented by pieces that break off naturally, for the action of animals (e.g. sea turtles, sharks, triggerfish) and humans (e.g. during maintenance/cleaning operations) and/or due to meteorological events (e.g. storms), within the same location as the nurseries. Fragments were carefully gathered and transported underwater by the operator in a perforated box to ensure adequate water flow and minimize damage during transit (2~7 min swim with scuba gear). Fragments from the same colony were evenly distributed between the rope and metal frames for consistency, having a total of 180 coral fragments (Figure 6). Coral fragments were attached to the ropes or metal frames with cable ties (3.6 mm × 200 mm). The first monitoring was carried out 1 week after the planting of the coral fragments to evaluate their response to mechanical stress, and then bimonthly (once every two months). Coral collection and planting was conducted according to NOAA Coral Bleaching Heat Stress Alert Area predictions. These activities were carried out only during the “no stress” phase, increasing the survival chances of the colonies. Sea water quality was tested weekly onsite using HI98194 Multi-parameter Probe (HANNA Instruments, Singapore). The monitored parameters were Temperature, PH, Salinity, Conductivity and Dissolved Oxygen. No abnormal changes have been reported since 2016 in the study area and nearby coral reefs. 4.3 Data collection and analysis Bimonthly underwater surveys were conducted over a period of six months, from September 2023 to March 2024, to analyze the following parameters: (i) growth rate, (ii) ecological volume, (iii) health condition, (iv) presence of disease, (v) predation, and (vi) survival rate.
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