FISHERY BULLETIN: VOL. 71, NO. 2 



geneous variances in most instances could be 

 attributed to disparities between the ranges 

 of the independent variables of the regressions. 

 Elimination of high or low independent values 

 from one or both regressions usually resulted 

 in homogeneity. When the variances were 

 heterogeneous and the ranges of independent 

 variables were about the same in both regres- 

 sions, heterogeneity was attributed to intrinsic 

 properties within the samples and they were 

 considered significantly different. If the var- 

 iances of the regressions were homogeneous, 

 the analysis of covariance was continued and 

 the slopes were tested. The adjusted means 

 were tested if the slopes were not significantly 

 different at the 1% level. 



Analyses of covariance were performed be- 

 tween males and females in each sample before 

 interarea comparisons were attempted. No 

 sexual dimorphism was found. 



Bigelow and Schroeder (1953:222) contended 

 that the position of the rear of the upper jaw, 

 relative to the position of the eye, was a 

 dependable character for separating U. chuss 

 from U. tenuis. This character may not be 

 reliable because the position of the rear edge 

 of the maxillary depends on the extent to which 

 the mouth of the fish is open. A more accurate 

 method of quantifying the character was used 

 in this study. The distance from the snout to 

 the posterior margin of the maxillary (upper 

 jaw length) was compared to the distance from 

 the snout to the posterior margin of the orbit. 

 A second morphometric character used by many 

 authors to distinguish between U. chuss and 

 U. tenuis is the length of the ventral fin relative 

 to the position of the anus. However, Bigelow 

 and Schroeder (1953), Goode and Bean (1895), 

 and others have pointed out that this character 

 may not be dependable. An analysis was made 

 of the regression of ventral fin length on the 

 distance from the origin of the ventral fin to 

 the anus. 



Subjective observations suggest that U. tenuis 

 has a larger head and forebody than U. chuss. 

 Therefore, regression analyses were made of 

 the preanal length and head length on standard 

 length. Hubbs and Lagler (1958:25) advocate 

 measuring head length from the tip of the 

 snout to the "most distant point of the oper- 



cular membrane," which may vary, depending 

 on whether the fish's operculum is expanded 

 or closed tightly against the head. Head length 

 is defined here as the distance from the tip of 

 the snout to the upper, inner angle of the 

 opercular opening. Preanal length is defined 

 here as the distance from the tip of the snout 

 to the anus. 



RESULTS 



Meristic Analysis 



Number of Rays in Second Dorsal and Anal 

 Fins and of Abdominal Vertebrae (Figures 4-6) 



The statistical analyses for these three char- 

 acters yielded the same results for all com- 

 parisons. The analysis of variance showed 

 heterogeneity at the 1% level, and the Duncan's 

 test separated all samples of U. teituis from 

 U. chuss. There were no significant differences 

 among the samples of U. tenuis. 



Total Number of Vertebrae (Figure 7) 



Heterogeneity of variance was shown at the 

 1% level. Duncan's test showed significant dif- 

 ferences between U. chuss and both U. tenuis 

 N.E. and U. tenuis P.E.I. However, there were 

 no significant differences between U. chuss 

 and U. tenuis N.S., nor among the samples of 

 U. tenuis. 



U tenuis N E 

 JJ tenuis N S 

 U tenuis PE I 



50 52 54 56 56 60 62 64 



NUMBER OF SECOND DORSAL FIN RAYS 



Figure 4. — Comparison of the number of rays in the 

 second dorsal fin among three samples of Urophycis 

 tenuis and one of U. chuss. Range — horizontal line. Mean 

 (^) — small narrow triangle. Two standard errors of the 

 mean on either side of x — blackened part of each bar. 

 One standard deviation on either side of x — one-half of 

 each black bar, plus the white bar at either end. 



482 



