SEAWARD MIGRATION OF CHINOOK SALMON. 



17 



Table ii. — Fry from Point Ellice, Wash., Aug. 12 and 26, 1916 — Contd. 



THIRTY-SEVEN SPECIMENS WITH INTERMEDIATE GROWTH. 



Lensth. 



lai to 

 116 to 

 III to 

 106 to 

 lOI to 



96 to 

 91 to 

 86 to 

 81 to 

 76 to 



las mm. 

 1 30 mm. 

 J15 mm. 

 110 mm. 

 105 mm. 

 100 nun . 



9S mm. 



90 mm. 



85 mm . 



80 mm. 



, Av. 98.5 mm. 



Number. 



Scale record. 



Number of rings — 



To inter- 

 mediate 

 growth. 



13- o 

 13-5 

 13-0 

 9.0 

 9.1 

 9- a 



6-2 



7-5 

 6.0 

 6.0 



8-S 



In inter- 

 mediate 

 growth. 



7.0 

 8.0 

 7-5 

 9.0 

 7.3 

 8.2 

 9-3 

 8.0 

 S.8 

 6.0 



Total. 



20. O 



al-S 

 20.5 

 j8.o 

 i6. 4 



17-4 

 15-5 

 »5-5 

 II. 8 

 12.0 



16. 1 



Length oS anterior 

 radius — 



To inter- 

 mediate 

 growth. 



38.0 

 45-3 

 38.0 

 29.6 

 29.6 

 30.5 

 23-3 

 24.4 

 23.0 

 23.0 



28.2 



Total. 



63.0 

 68.0 

 SS-S 

 58.0 

 54.2 

 56.7 

 SI-3 

 43.0 

 38.0 

 43.0 



S'-i 



Average 

 estimated 

 length of 



fish at 

 beginning 

 of inter- 

 mediate 

 growth. 



73- o 

 80.5 

 73- o 



65-5 

 58.0 

 54. a 

 44.1 

 it-S 

 SI.3 

 48.0 



M-S 



Three specimens of young chinook salmon were caught August 23, 191 6, by hook 

 and line from the wharf of P. J. McGowan & Sons at Ilwaco, Wash. These young 

 fish were under the cannery and were feeding voraciously on the offal resulting from 

 the cleaning of the adult salmon. Their stomachs were quite filled with eggs and 

 small pieces of kidney, flesh, etc. There was very little evidence that they had been 

 feeding on insects or crustaceans. Several other collections were made under this can- 

 nery and one other in Astoria, and in every case the young fish were found to have 

 eaten heavily of the offal. These three specimens are all females averaging 118 mm. 

 in length. The scales of one specimen show a distinct intermediate band of eight rings. 

 The average number of rings on the scales is 21.3. The length of the anterior radius 

 averages 61.3. 



Ten specimens of young chinooks were collected in the Clackamas River, August 

 30 and 31, 1916. (See Table 12.) The collection was made by hook and line near the 

 Clackamas hatchery, about 2 miles above where the Clackamas River flows into the 

 Willamette. Five of these are males averaging 1 13.8 mm. in length. The five females 

 average 112 mm. Four of the males were approaching maturity, as was indicated by 

 the enlarged and white testes. The average length of these four is 118. 2 mm. The 

 scales of these precocious males are in every respect similar to the scales of the other 

 individuals. Such precociously matured males have been previously described by 

 Rutter (1903). The scales of these fish indicate unmistakably that they were fry, less 

 than I year old. The scales of 8 out of the 10 individuals show a distinct narrowing 

 of the marginal rings corresponding to the slower growth of the fall and winter. Since 

 the number of specimens is so small, no attempt is made to segregate the specimens 

 showing different types of scale growth. 



