SEAWARD MIGRATION OF CHINOOK SALMON. 



15 



One hundred and sixty-six specimens of migrating fry were captured at Point 

 Ellice, July 19, 1916. (See Table 10.) The average length is 92.1 mm., ranging from 

 60 to 1 28 mm., with the mode at 93 mm. It will be noted that here and in the subsequent 

 tables there is very little skewing of the curve of length toward the lower end. This 

 indicates, undoubtedly, that no more of the smallest fry are being added from the upper 

 waters. This is proved by the fact that no fry less than 60 mm. in length were taken. 

 Such fry as are entering the estuary from above must be more nearly the same size as 

 the fish already in the estuary. 



The scales of these fish show an average of 12.9 rings. One hundred and sixteen 

 have started a more rapid intermediate growth, which is indicated on the scales by a 

 marginal band of wider rings. There is an average of 7.6 rings within the intermediate 

 band, the band itself comprising 5.3 rings. Seventy-six of the specimens are males, 

 averaging 90.1 mm. in length. Ninety females average 93.6 mm. 



Table 10. — Fry from Point Ellicb, Columbia Estuary, July 19, 1916. 

 fifty specimens without intermediate growth. 



L^'ngth. 



XII to 

 106 to 



101 to 



96 to 

 91 to 

 86 to 

 81 to 

 76 to 

 . 71 to 

 66 to 

 61 to 

 56 to 



115 mm. 

 no mm. 

 105 mm. 

 100 mm. 



95 mm. 



go mm. 



85 mm. 



80 mm. 



75 mm. 



70 mm. 



65 mm. 



60 mm. 



Av. 89.9 mm. 



Number. 



Scale record. 



Average 



number cf 

 rings. 



14-3 



II. o 



iS-o 

 13-2 

 12.6 

 10.6 

 10.5 

 II- 4 

 10. o 

 10. o 

 9.0 

 9.0 



11-9 



Average 

 length of 

 anterior 

 radius. 



66.3 

 48.0 

 56-7 

 5=-8 

 48.0 

 43- o 

 40-.'; 

 40.0 

 33-0 

 33-0- 

 33-0 

 =S.o 



46.4 



ONE HUNDRED AND SIXTEEN SPECIMENS WITH INTERMEDIATE GROWTH. 



Length. 



Number- 



Scale record. 



Number of rings — 



To inter- 

 mediate 

 growth. 



In inter- 

 mediate 

 growth- 



Total. 



Length of anterior 

 radius — 



To inter- 

 mediate 

 growth. 



Total. 



Average 

 estimated 

 length of 



fish at 

 beginning 

 of inter- 

 mediate 

 growth. 



126 to 



l::l to 



116 to 

 itr to 

 106 to 



lOI to 



96 to 

 91 to 

 86 to 

 81 to 

 76 to 

 71 to 

 66 to 

 61 to 



130 mm- 

 125 mm. 

 120 mm. 

 115 mm. 

 no mm. 

 105 mm. 

 100 mm. 



95 mm. 



90 mm. 



85 mm. 



So nun. 



75 mm. 



70 mm. 



65 mm. 



Av. 93.1 mm. 



9.6 

 9.2 

 7-7 

 8.4 

 8.0 

 7.3 

 7-3 

 7-2 

 6.9 

 6.1 

 S-o 

 6-5 



7.6 



7-1 

 7-3 

 7.0 

 6.9 

 5-4 

 5-6 

 4.9 

 4.2 

 4-7 

 4.0 

 5.0 

 S-o 



28.0 



16.7 

 16.5 

 14.7 

 IS- 3 

 13-4 

 12.8 



12. 2 

 II. 4 



II.6 



II. 2 

 10. o 

 II- 5 



13- 1 



37- o 

 30- S 

 30-8 

 31-3 

 30.2 

 28.5 

 27-1 

 27. 2 

 24-4 

 31. 



13-0 

 93.0 



28.3 



78.0 



63-0 

 60.8 

 57- o 

 56. 5 

 5I-0 

 48.3 

 44-9 

 41-3 

 39- S 

 36-4 

 28-0 

 35- S 



49-8 



43- o 



76- S 



60. s 

 54- S 

 58.0 

 60- s 

 54- S 

 55- S 

 52-5 

 47-3 

 43-0 

 38-0 

 50-5 



