FISHERY BULLETIN: VOL. 87, NO. 4. 1989 



3 mm 



Figure 3. — Thin tranverse cross section of the 2nd anal spine from a 138.3 kg 

 female Pacific Makaira nigricans as viewed by a binocular dissecting microscope 

 at 63 X magnification with transmitted light. Arrows indicate translucent edges 

 of growth bands, F = focus; M = core matrix. 



ridges along the anterior rostrum edge (Fig. 5). 

 Between two and four ridges were counted along 

 the anterior edge of the rostrum. Ridges were 

 also visible along the ventral portion of the 

 medial plane of growth (Fig. 6). Most sagittae 

 had an excess of calcium carbonate which hin- 

 dered ridge quantification to varying degi-ees 

 (Fig. 6). Several sagittae were difficult to inter- 

 pret owing to the mottled appearance of the 

 rostrum face. 



Vertebrae contained numerous minute 

 (0.05-0.1 mm) concentric growth increments 

 which were topographical features on the 

 centrum face (Fig. 7). There were no prominent 

 3-dimensional features or changes in ring den- 

 sity which might be indicative of annular 

 events. 



Increment Counts and Hardpart Growth 



Statistical replacement of early missing anal 

 and dorsal spine bands in larger fish was accom- 

 plished by summarizing band radii statistics 

 from smaller fish in which these early incre- 

 ments were visible (Fig. 4). Twenty-one percent 

 of anal spines and 24% of dorsal spines had at 

 least the first and second assumed annulus visi- 

 ble. There was no significant difference (P < 



Figure 5. — Right sagitta from a 35.2 kg female Pacific 

 Makaira nigricans. Arrows indicate prominences quanti- 

 fied for estimation of early lateral rostrum growth. R = 

 rostrum; A = antirostrum; C = core region; p = posterior; a 

 = anterior. 



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