Existence, growth and reproduction of pearl oyster Pinctada margaritifera in Hadhramout coast/Gulf of Aden

This study was conducted to confirm the existence, morphological and biological attributes; growth indicators and reproduction of pearl oyster, Pinctada margaritifera in Hadhramout coast. The samples were collected from around coral colony bases from the shore bays of the city of Mukalla, Broom and Bir Ali Islands through the period September 2009–November 2010. 213 specimens were collected from shallow habitat at intertidal zone, subtidal up to more than 15 m in some places. Its morphological characteristics were described. The results show a strong positive correlation (R2 = 0.9836) between the biometric parameters (ShH and ShL) of P. margaritifera, with an equation of: Shell Length = 0.992 × Shell height0.995. The maximum size of the recorded species was180 mm. Growth rates retreated with age from an average of 34.6 mm/2nd year to 3.7 mm/the 7th year. The dominant proportion of ripe mature specimens was recorded in December 2009–March 2010 in females and along two periods in males – January–March and August–October 2010. The data showed that mean gonadic index (GI) transition of males and females followed nearly the same pattern. The results revealed that the occurrence of both adults and juveniles individuals indicates that the Hadhramout coastal environment is suitable for the growth and reproduction of pearl oyster.