Distribution patterns and ecological aspects of the sea urchin Diadema stosum in the Red Sea, Egypt. | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 8, Volume 23, Issue 4, October 2019, Pages 93-106 PDF (526.41 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.2019.52592 | ||
| Author | ||
| Mohamed Hamza Hasan | ||
| Abstract | ||
| Diadema setosum populations were surveyed at three sites representing different habitats of the Red Sea; El-Giesum at the northern Red Sea, Ras Mamlah at the Gulf of Aqaba and Beer Odeeb at the Gulf of Suez. A comparison among these sites was carried out for distribution patters, habitat preference and the character of habitat, which is preferred byD. setosumin addition to its role in the ecosystem at each site. At Beer Odeeb, the population density from sand recorded 1-2.3 ind./m2, seagrasses 1.7-3.8 ind./m2, rocks 2.1-7.9 ind./m2, while it recorded its maximum densities at dead and live coral habitats. At Ras Mamlah the density recorded its minimum at sandy habitats (0-1.3 ind./m2) and its maximum at live coral habitats (2.3-28.9 ind./m2). The same pattern was recorded at El Geisum its minimum was at sandy habitat (0-0.3 ind./m2) and its maximum was from live coral habitat (1.3-32.4 ind./m2). Abundance of D. setosum was highest at El Giesum (163240 individuals) with 68.2% of the population recorded from the live coral habitat, followed by Ras Mamlah at the Gulf of Aqaba that recorded abundance of 87335 individual; live coral habitat accommodated 69.7% of the population. Finally, Ber Odeeb site at the Gulf of Suez recorded the lowest abundance (28176 individuals), with the highest percentage recorded from dead coral habitat being 34.8%, while live coral habitat at this site accommodated 24.3% of the population. The distribution pattern of D. setosum populations was determined using the coefficient of dispersion. The study revealed a difference in dispersion among the different habitats and sites. One way ANOVA revealed that the habitat preferences are varied according to the sites, areas on the reef and habitats. The three sites shared the preferable areas for the urchin, which are the fore reef and 5m depth, while the reef crest was not favorable for urchin existence. In conclusion, the study revealed that live and dead corals environment were the most preferred habitat for D. setosum, in contrast, sand, seagrasses and rocky habitats were unfavorable. The species showed habitat preference according to the physical conditions and different habitats at each site. The presence of the urchin in this habitat is essential for protecting the coral fauna and for the health of the environment. | ||
| Keywords | ||
| Sea Urchin; Diadema setosum; density; Abundance; habitat preference; Red Sea | ||
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