218 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



30 



40 



50 60 70 80 



% SLOPE OF TRANSFORMATION 



90 



100 



Figure 8. — Regression of transformation values calculated for individual pilchard of 1939-class caught at the 6-ring 

 stage, asymptotic length (/„) on rate of deceleration of growth (A-). Dots represent individuals taken in Canada, 

 circles San Pedro, symbol x San Francisco, symbol Q Monterey. 



from false rings in opercula of perch, and appears 

 a satisfactory means of photographing pilchard 

 scales. 



Hessle (1925) gives illustrations of scale types 

 which show differing growth patterns in various 

 races of Baltic herring. The autumn-spawning 

 herring which spawn in coastal waters (never inside 

 archipelagoes) show rapid growth (hiring the first 

 •'! years and subsequent rapid falling off in growth 

 increments. This is likewise the growth pattern 

 of the somewhat smaller, spring-spawning sea her- 

 ring of the Baltic in the same region. (The pat- 

 tern corresponds to pilchard growth with a low k 

 value, or rapid rate of deceleration in growth.) 

 The fjord herring, on the other hand, also spring 

 spawners, are sometimes quite isolated and show 



great variability in size with some dwarf ami some 

 giant forms. Ilessle notes (p. 37) that "these two 

 herring forms [dwarf and giant] show a striking 

 similarity as regards actual mode of growth." lie 

 figures (p. 40) the "even growth" typical of all 

 the fjord herrings as contrasted with the "stagnant 

 growth" (pp. 17, 33) of sea herring of the Baltic. 

 He also found (p. 45) ice herring in the Gulf of 

 Bothnia with a growth pattern and spawning 

 habits similar to the fjord herring. He concludes 

 thai - 



mode and rate of growth seems ... to be very like that 

 of the most rapid-growing fjord-herrings of the Middle 

 Baltic. It is therefore natural to suppose thai these 

 spring-spawners of the Gulf . . . are closely related to 

 the fjord-herring of the Middle Baltic. 



