SEAWARD MIGRATION OF CHINOOK SALMON. 



21 



Table 15. — Young Chinooks from Under the Cannery, Ilwaco, Wash., Sept. 17, 1914. 

 seven specimens \\athout intermediate growth. 



TWENTY-EIGHT SPECIMENS WITH INTERMEDIATE GROWTH. 



Length. 



Number, 



Scale record. 



Number of rings — 



To inter- 

 mediate 

 growth. 



Length of anterior 

 radius — 



To inter- 

 mediate 

 growth. 



Total. 



Average 

 estimated 

 length of 



fish at 

 beginning 

 of inter- 

 mediate 

 growth. 



i^i to 

 146 to 

 I41 to 



136 to 



131 to 

 126 to 



i;i to 

 116 to 

 III to 

 106 to 

 10 1 to 



155 mm. 

 150 mm. 

 145 mm. 

 140 mm. 

 13s mm. 

 130 mm . 

 115 mm 

 120 mm . 

 115 mm. 

 no mm . 

 105 mm. 



Av. 123.5 mm . 



17.0 



53- o 



88.0 



98.0 



17-0 



25- o 

 30- O 



17- o 



18.6 

 16.6 



i6. 3 



24.5 



30.0 

 23-0 



20 ■ 3 

 19-6 



55- o 

 53- o 

 53-0 

 48-0 

 50.0 

 47- o 

 45- o 



75- o 

 78.0 

 s8-o 

 6i.o 

 6o- o 

 59- o 

 SS-o 



205*0 



98-0 

 iiS-o 

 100. o 

 105. o 

 95- o 

 89-0 



40.0 



6o.o 



48-1 



70.0 

 96-8 



Seven specimens were collected from the Clackamas River near the hatchery on 

 October 13, 191 5. These were obtained by hook and line fishing, and the collection is 

 too small and too variable to deser\"e detailed attention. The average length is 118 mm., 

 and the average total number of rings on the scales, 21. Several show the primary 

 check, and one at least had apparently started a new period of vigorous growth. This 

 is indicated on the scales by a marginal band of five slightly wider rings. The scales of 

 all of the other specimens terminate in rings of the winter type. 



October 16, 1915, a collection consisting of 119 young chinooks was made at Point 

 Ellice, Wash. The total average length is 11 2.7 mm. Sixty-one males average 112.2 

 mm. and 58 females 11 3.3 mm. Twenty-nine specimens (24 per cent) have a distinct 

 intermediate band at the margins of the scales. The scales of the remaining 90 speci- 

 mens terminate uniformly in narrow winter rings. The scales of a considerable pro- 

 portion show the primary check about 9 or 10 rings from the center. The following 

 table (16) presents the data. 



