Morphologic and Morphometric Analysis and Growth Rings Identification of Otoliths: Sagitta, Asteriscus and Lapillus of Yellowfin Tuna Thunnus albacares (Bonaterre, 1788) (Pisces: Scombridae) in the Eastern Pacific

摘要

A morphologic and morphometric analysis was conducted on three types of otoliths of yellowfin tuna Thunnus albacares (Bonaterre, 1788), as well as the identification of the growth rings in the sagittae and asterisci. The relationship among length, width and weight of the sagittae is expressed by the following equations: y = 0.706x0.989 (rostrum-antirostrum), y = 0.444x0.828 (rostrum-width) and y = 0.00007x2.696 (rostrum-weight). In the case of the asterisci: y = 0.860x0.694 (length-width) and y = 0.0004x1.023 (length-weight). For the lapilli y = 1.038x0.488 (length-width) and y = 0.0004x1.077 (length-weight). The growth of these otoliths was related to the length of the fish. The average length was calculated for each of the six growth rings identified in the sagittae and the asterisci; the results are: 1 = 64.00 cm, 2 = 102.60 cm, 3 = 128.50 cm, 4 = 160.00 cm, 5 = 167.00 cm and 6 = 173.00 cm. Also the average length at each age was compared with those of yellowfin tuna of the tropical Atlantic and Pacific Oceans.