294 



Fishery Bulletin 89(2). 1991 



Figure 4 



Means and individual 95% confidence intervals based 

 on pooled standard deviations for morphometric 

 characters adjusted for total length, for five yellowfin 

 tuna sample areas in the Pacific Ocean, and the order 

 in which they entered the stepwise discriminant anal- 

 ysis. Character acronyms are defined in Figure 2. 



Discussion 



The results of these analyses of morpho- 

 metric characters and gill-raker counts 

 suggest that each of the areas included 

 in this investigation is inhabited by a 

 discrete group of yellowfin tuna. 



Yellowfin tuna from the eastern Pacific 

 are morphologically more similar to one 

 another than are fish from the central 

 and western Pacific, as shown by the 

 amount of overlap in the samples from 

 Mexico and Ecuador relative to those of 

 Australia, Japan, and Hawaii (Fig. 3). 

 The overlap of samples from the eastern 

 Pacific may be due to a greater degree 



