SEAWARD MIGRATION OF CHINOOK SALMON. 

 Table 29. — Chinook Fry from the Sacramento River. 



33 



Locality. 



Number. 



Average 

 length 

 (mm.). 



Scale record. 



Average 

 number 

 of rings. 



Average 

 length of 

 anterior 

 radius. 



1910. 

 Mar. 5 



1911. 

 Mar. 8 

 Apr. 3 

 Apr. 13 

 Apr. 19 

 Apr. 29 

 May 9 

 May IS 

 May 16 

 May 27 

 May 28 

 June 8 

 June 30 

 July 9 



1913. 

 Jan. 4 



Brookdale hatchery 



Sisson hatchery 



do 



Sacramento River, 30 miles above Sacramento 



Cache Slough 



Prospect Slough 



Pond near Butte Slough '. 



Shag Slough 



Hass Slough 



Sausilito, Calif 



Prospect Slough 



Pond near Butte Slough 



Ponds near Knights Landing, Calif 



Pond near Butte Slough 



Brookdale hatchery 



36.3 



38.7 



41.2 



57- S 



67 



69 



81.5 



77 



75-2 



81 



63 



95-6 



C«) 



m 



(')2.0 



4.4 

 6.0 



7-S 

 9-2 

 9.9 

 9-S 

 10. 9 

 7-S 

 133 

 i6' 4 

 14-8 



(») 



) 



)I7 



23 -6 



28.2 



27.6 



37-5 



34- S 



32-2 



37-5 

 28.3 

 48.9 

 51-4 

 47-9 



33.9 



o No scales formed. 



^ Only a few platelets present on the largest specimens. 



c Average of six of the largest. 



li IS specimens without new growth. Four specimens with new growth show: Average nimaber of rings to new growth. 16.7; 

 of new growth, 3.7; average length of anterior radius to new growth, 37.4; total length of anterior radius, 44.9; and average esti- 

 mated length at time of beginning new growth, 92.9. 



The following tables (30, 31, and 32) contain the data for those collections of wild 

 fish which are large enough for separation into the various size groups to be of value: 

 It was not considered necessary to present in detail the data for the collections from the 

 Brookdale hatchery, although these are as large as many of the collections of wild 

 fish so considered. The fry preserved March 5, 1910, have no scales and present only 

 a slight variation in length. The series of yearlings, preserved January 4, 1913, are 

 so variable and the scale growth is so irregular that they can not be compared in detail 

 with the wild fish. 



TablK 30. — Data for 19 Fry from Walnut Grove, Calif., Apr. 9, 1911. 



Length. 



Scale record. 



Average 



number of 



rings. 



Average 

 length of 

 anterior 

 radius. 



71 to 75 mm. 

 66 to 70 mm , 

 61 to 65 mm. 

 56 to 60 mm., 

 51 to 55 mm., 

 46 to 50 mm., 

 41 to 45 mm.. 

 36 to 40 mm . , 

 31 to 35 mm. . 



Av. 49.0 mm. 



26. s 



