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TOTAL LENGTH IN MILLIMETERS 



(BY 2 MM LENCTM GROUPS) 



100 



90 



O 80 



70 



60 



40 



30 



20- 



10 



LARVAL LAMPREYS 



TAKEN FROM BEDS AT 



STATION 2 



OCQUEOC RIVER 



AUGUST, 1947 



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I ixTTSi I ] ] I 



I I I I I J-^' I I I I I I I I I I I 1 1 







ooioo — — — c\jc\jf^nrn^ 



. ^ iD Oi n . 



't iT) lO If) »o <^ 



TOTAL LENGTH IN MILLIMETERS 



{BY 2 MM. LENGTH GROUPS) 



Figtire 53. — Distribution of the sizes of larvae taken from two beds 

 of differing characteristics in the Ocqueoc River: 



Upper histogram . — Larvae taken from a silted and .muck-bottoraed 

 channel. The stream bed here is relatively s table from year to 

 year. Young-of-the-year larvae were equally abundant at this sta- 

 tion as in the following but were not deliberately collected and 

 measured, A few are represented to show the size range of this age 

 group. 



Lower histogram . — Larvae taken from a bed of mixed silt and 

 sand situated on the inside of a bend in the river and just above 

 the station for which data is presented in the upper histogram. 

 This bed is unstable in character, changing its conformity each year 

 with flood conditions. The young-of-the-year, represented by the 

 most left-hand distribution, were twice as numerous as indicated; the 

 scale of their occurrence was halved to render the diagrams more com- 

 pact. 



- lUU - 



