POPULATION HETEROGENEITY IX PACIFIC PILCHARD 



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I Northern type from Canada (249-mm. female 



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(2) Northern type from .San Pedro (241-mm. female) 



Figure oa. — Growth types of Pacific pilchard at 4-ring stage as shown in scale patterns. These scales show the well- 

 defined annual rings of large fish caught commonly in the north, but also entering the southern fishery. They have 

 a proportionately small first-growth increment and a rapid rate of deceleration in growth. 



