"To Hit et al.: A method to improve size estimates of Theragra chakogramma and Pleurogrammus monopterygius 



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Figure 2 



Photographs showing the changes in morphological features in seven cranial structures of Atka mack- 

 erel (Pleurogrammus monopterygius) resulting from digestion. Within each section of the figure three 

 condition categories (good, fair, and poor) are represented from left to right for (A) interhyal (INTE), 

 (B) hypobranchial 3 (HYPO), (C) angular (ANGU), (D) quadrate (QUAD), (E) dentary (DENT) and 

 (F) sagittal otolith (OTO). Key features used in classification are labeled (see Table 1 for details) and 

 measurements taken to calculate fish length (solid line between dashed lines). 



(Figs. 1 and 2). The morphological features used to as- 

 sess level of digestion showed no differences in relative 

 shape, structure, or in proportion across the size range 



of fresh fish examined. We then devised a criteria-based 

 method to assign a condition category to each structure 

 depending on the degree of digestion. These criteria 



