Pearson and Shaw: Age determination errors for Anop/opoma fimbria 



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Figure 4 



Images of four otolith morphological types. (A) Otolith is a wide type, (B ) otolith is a wide, 

 wedge subtype. (C) otolith is a thick type, and (D) otolith is a thick, wedge subtype. 



To determine if age determination difficulties were relat- 

 ed to sex, size, area of capture, depth of capture, or otolith 

 morphological type; Fisher exact tests were performed. In 

 each test, the variables were compared to whether the fish 

 had been correctly aged, over aged, or under aged. 



Results 



Recoveries 



A total of 2575 fish were tagged at the nine sites, and 368 

 tagged fish were recaptured. Of the recaptured fish, 284 

 had been injected with OTC. Of the 284 injected fish, usable 



otoliths were recovered from 191 fish; for the remaining 

 fish, otoliths either were not recovered or were too badly 

 damaged during removal to be used. 



Otolith morphological types 



After examination of all the otoliths, "wide" and "thick" 

 morphological types were identified, and each type had a 

 "wedge" subtype ( Fig. 4 ). Each otolith in the study was then 

 classified according to this scheme. 



The wide type (Fig. 4A) is characterized by new growth 

 that steadily increases cross sectional width along 

 the dorsal and ventral surfaces. In the wedge subtype 

 (Fig. 4B), initial growth increases the width, but the most 



