Population ecology, reproduction and locomotion of the sand dollar Sculpsitechinus auritus in the Gulf of Suez, northern Red Sea
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The population ecology of the sand dollar Sculpsitechinus auritus was studied in shallow coastal habitats of the Gulf of Suez, Egypt, from January 2013 to October 2014. Bimonthly sampling revealed that 95 % of the individuals had a width of 100–145 mm and that juveniles were absent throughout the sampling period. The mean gonadosomatic index (GSI) reached peaks of >2 % in September 2013 and August 2014, which concurred with seasonal highs of water temperature. Declining GSI values indicated that spawning took place between October and January. Histological examination of the gonads confirmed that spawning started in October. Locomotion rate was 88.7 mm h−1 in September, which was significantly higher than 56.3 mm h−1 in December. Similarly, water temperature was significantly higher in September (26 °C) than in December (17 °C), most probably explaining locomotion differences. Organic matter and grain size fractions of the sediment were not significantly different. Maximum density of 0.68 individuals m−2 was found at 4 m depth, whereas at other depths densities were significantly lower (≤0.05 individuals m−2). The epibiotic brittle star Ophiodaphne scripta was found on >67 % of the sand dollars and its frequency was significantly higher (>1.5 per host) between September and November coinciding with the onset of S. auritus’s spawning period.
Bos, A. R.
(2018). Population ecology, reproduction and locomotion of the sand dollar Sculpsitechinus auritus in the Gulf of Suez, northern Red Sea. Marine Biodiversity, 48(2), 1213–1221.
Amleh, Asma, et al.
"Population ecology, reproduction and locomotion of the sand dollar Sculpsitechinus auritus in the Gulf of Suez, northern Red Sea." Marine Biodiversity, vol. 48,no. 2, 2018, pp. 1213–1221.