Farasan Island Research Articles

Breeding ecology of the Kentish Plover, Charadrius alexandrinus, in the Farasan Islands, Saudi Arabia

The breeding behaviour and ecology of the Kentish Plover, Charadrius alexandrinus Linnaeus, were investigated in three consecutive years in the Farasan Islands, Saudi Arabia, where the species breeds either under halophytic bushes or in exposed sites where ground temperatures may reach 60°C. Three aspects make the Farasan Island population distinct from most other Kentish Plover populations studied to date. First, incubating plovers appear to prefer nesting under halophytic bushes rather than in exposed sites, since 65.1% of nests were under bushes, whereas 34.9% of nests were in fully exposed sites. Second, both mate fidelity and nest-site fidelity were high, and pairs stayed within short distances from their previous nest sites. Third, brood desertion was very rare in the Farasan Islands – unlike most other populations where the female or the male deserts the brood shortly after hatching of the eggs – since in 95% of broods both parents attended the chick(s) (n=153 broods). We suggest that these social traits are driven by the extreme hot environment that requires parental cooperation, although adaptation to island-dwelling and corresponding changes in life-history traits cannot be ruled out.

Mass occurrence and toxicity of the cyanobacterium Lyngbya majuscula under phosphorus-limited conditions in the Red Sea

Large mass of Lyngbya majuscula has occurred on the surface of coral reefs in Farasan island in the Red Sea, Saudi Arabia. It was also observed that dermatitis symptoms appeared on people bathing and swimming in this area. The present study describes the toxicity of field samples and batch cultures of L. majuscula to Artemia salina and mice, and investigates effects of inorganic and organic phosphates on the growth and toxicity of this cyanobacterium during batch experiments. The extract of field samples of L. majuscula, was highly toxic to A. salina with LC50 value of 2.8mg cm−3. This extract also showed a moderate toxic effect to intraperitoneally injected mice (LD50=425mg kg−1), and highly dermatotoxic effect including skin redness and inflammation within 24 hours upon application to shaved back of mice (LC100=88mg dm−3). In addition, the study revealed that the growth of L. majuscula increased by increasing inorganic and organic phosphate concentrations. In contrast, the highest toxicity of this cyanobacterium was obtained in phosphorus -depleted cultures, and decreased by increasing phosphate concentration in the medium. The results of phosphatase activity assay revealed a high enzyme activity (8.6μmol pNP mg−1 dry wt h−1) of the field samples of L. majuscula. The activity increased by increasing organic phosphate concentrations, but decreased with high inorganic phosphate concentrations during batch experiments. The present study suggests that L. majuscula mats could be the causative agent in dermatitis developed in swimmers and bathers in Farasan Island waters, and that formation of these mats would be enhanced by organic phosphate resulting from human activities and rotted seaweeds.

Unique Annual Aggregation of Longnose Parrotfish (Hipposcarus harid) at Farasan Island (Saudi Arabia, Red Sea)

Unique Annual Aggregation of Longnose Parrotfish (Hipposcarus harid) at Farasan Island (Saudi Arabia, Red Sea)

Sickle cell gene in the population of Saudi Arabia.

A comprehensive screening program was initiated in Saudi Arabia in 1982 to determine the frequency of the sickle cell (Hb S) gene in the different regions of Saudi Arabia. Over a period of 10 years 30,055 samples were collected from 36 areas in the five provinces of Saudi Arabia; these were screened using electrophoretic techniques in alkaline and acid pH for the presence of Hb S in heterozygous and homozygous states. The overall prevalence of Hb AS was 7.36% and Hb SS was 1.06%, giving an Hb S gene frequency of 0.047. The results from the different regions were separated and the prevalence of Hb AS and Hb SS and Hb S gene frequencies were calculated in each province and each region. The prevalence of Hb AS and Hb SS cases ranged from O to 25.88% and O to 5.27%, respectively. No case of Hb AS or Hb SS were identified in certain areas of the central province (Al-Russ, Al-Unaiza, Al-Mesnab and Bkaria) and northern province (Qurayat and Al-Jouf). In the southern province both Hb S homozygotes and heterozygotes were encountered in all regions except Farasan Island. In all other regions the Hb S gene was encountered, but at a variable frequency. Applying Hardy-Weinberg equilibrium it was observed that in the majority of the regions the observed Hb S homozygotes were significantly higher compared to the number expected (p < 0.0001). This was believed to be due to bias as the samples were collected in the hospital. The Hb S gene frequency in the different regions ranged from 0 to 0.17 when the frequency was calculated on the basis of both Hb AS and Hb. SS cases, and 0 to 0.13 if the gene frequency was calculated after eliminating the Hb SS cases. A close correlation was observed between the Hb S gene frequency and malaria endemicity. This study shows that the Hb S gene occurs frequently in several regions of Saudi Arabia and there is an urgent need to implement control and prevention programs to reduce the number of Hb S homozygous cases.