SHELL GROWTH CHECKS AND GROWTH OF THE OMANI ABALONE HALIOTIS-MARIAE

Settlement of the Omani abalone Haliotis mariae Wood on the Dhofari co ast in 1992 occurred from January until April. Growth was measured by analysis of modal progressions of cohorts in length-frequency data, ma rk-recapture data and frequency of primary growth checks. The annual i ncrease in shell length was about 43 mm in the first year and 20-25 mm in the second and third years. Primary and secondary growth checks in the shell were caused by spawning and seasonal factors. Parameters of fitted von Bertalanffy growth curves were K = 0.27-0.43 per year and L(infinity) = 139 to 149 mm according to site. Examination of the rate of deposition of rings in the spire indicated that four rings per yea r were laid down, but that one ring per year was lost through erosion of the shell.