SHELL MORPHOMETRICS AND SOME BIOCHEMICAL ASPECTS OF THE PEARL OYSTER PINCTADA-RADIATA (LEACH 1814) IN RELATION TO DIFFERENT SALINITY LEVELSAROUND BAHRAIN

Shell morphology of the pearl oyster Pinctada radiata (Leach 1814) col lected from three different geographical areas on the north, east and west coast of Bahrain was analyzed. Muscle protein profiles and isozym es, using PAGE and SDS-PAGE, characteristics for these oysters were al so studied. Substantial variation in shell morphometry was obtained wi th predominance of large-sized individuals (65-66, 75-80 mm) at both t he north and the east coast, respectively, where the salinity levels w ere 40-42 parts per thousand. Consistently smaller pearl oysters (35-4 0 mm) prevailed on the west coast of Bahrain where salinity levels ran ged from 50 to 60 parts per thousand. Some variations were observed am ong the phenotypic groups, only when PAGE and isozyme analyses were ap plied. In general, both approaches gave initially identical results wi th regard to the phylogenetic relationship of pearl oysters living in areas of differing salinities. SDS-PAGE gave no detectable differences among oysters from different sites.