Manual of best practices for age determination of North Pacific Albacore Tuna /

Knowledge of the 3 location of the primordium is important for the correct interpretation of the banding pattern on an otolith. [...] The rostrum is the anterior section of the sagittal otolith, while the postrostrum is the posterior area (Fig. [...] The primordium, the initial part of the otolith where growth first begins, is a blob of dense material located in the central core of the otolith. [...] The first ray from the first dorsal fin of Mediterranean Albacore Tuna was studied by Megalofonou (2000), and the first and second dorsal spines of Atlantic Albacore Tuna were studied by Santiago and Arrizabalaga (2005) and it was reported in both studies that spines are harder to interpret with increasing age due to the occurrences of resorption and vascularization obscuring the spine core (Megal [...] First, the diameter of the spine just above the spine base, directly above the hollows is measured 6 and the cut axis is marked above the measuring line, at half the length of the measured diameter (Fig.