| The age and growth of Bigeye tuna from the western Indian Ocean was investigated using both otolith and first dorsal spine. Microincrements, considered as daily depositions , were observed on transverse section of sagittal otoliths of 154 bigeye tuna (Thunnus obesus); they were counted to determine age and establish growth curve. The von Bertalanffy growth curve is FL = 303.9 (1 – e-0.000397 ( t+167.15)), where FL is fork length in cm and t in days. The fish reaches 58 cm at 1 year, 91 cm at 2 years and 120 cm at 3 years of age. We also studied growth by analysing marks on the first dorsal spine of 140 fish. For fish which are 1 and 2 years old, the results obtained with spine and otoliths are comparable, but they are different for older fish . 'Research... |
