SEAWARD MIGRATION OF CHINOOK SALMON. 

 Table 29. — Chinook Fry from the Sacramento River. 



33 



Date. 



Locality. 



Scale record. 



Average 

 number 

 0/ rings. 



Average 

 length of 

 anterior 

 radius. 



1910. 

 Mar. 5 



1911. 



Mar. 8 



Apr. 3 



Apr. 13 



Apr. 19 



Apr. 39 



May 9 



May 15 



May 16 



May 27 



May 28 



June 8 



June 30 



July 9 



1913- 

 Jan. 4 



Brookdale hatcher>' 



Sisson hatchery 



do 



Sacramento River, 30 miles above Sacraxneato 



Cache Slough 



Prospect Sloueh 



Pond near Butte Slough 



Shag Slough 



Hass Slough 



Sausilito. CaUf 



Prospect Slough 



Pond near Butte Slough 



Ponds near Knights Landing. Calif 



Pond near Butte Slough 



Brookdale hatcherj- 



C«) 





4-4 

 6.0 

 7-S 

 9.2 

 9.9 

 9-5 

 10.9 

 7-S 

 13-3 

 16-4 

 14-8 



(«) 



CM 



23-6 

 38-2 

 27.6 



37- S 

 34- S 

 32-3 

 37- S 

 28.3 

 48-9 

 5»-4 



38.9 



« So scales formed. 



^ Only a few platelets present on the largest specimens. 



' Average of six of the largest, 



I* 15 specimens without new growth. Four specimens with new growth show: Average number 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, preser\^ed January 4, 1913, are 

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

 vnth the wild fish. 



Tablk 30. — Data for 19 Fry from Walnut Grove, Calif., Apr. 9, 191 1. 



Length. 



71 to 7s nmi 



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. 



Number. 



Scale record. 



Average 



number of 



rings. 



S 



7-3 



4-5 



3-5 

 3-0 



Average 



length of 

 anterior 

 radius. 



32.2 

 36. 5 



33-6 



33.6 

 14-9 

 14.9 



