CONTENTS 



Page 



Introduction 1 



Materials and methods 2 



Release of marked lake trout 2 



Recoveries 2 



Preparation and examination of scales 5 



Basis for rejection of samples from southern Lake Michigan 6 



Geographical distribution of recoveries 7 



Fins on recovered lake trout 7 



Discrepancies between ages read from scales and indicated by abnormal fins 7 



Growth as indicated by abnormal fins 8 



Validity of age determinations from scales 9 



Early growth of scales '■' 



Characteristics of the annulus 11 



Time of annulus formation I'.l 



Supernumerary or O mark 26 



Agreement between first and second readings 2!» 



Agreement between ages read from scales and ages fixed by deformed fins 30 



Factors of disagreement 31 



Errors of reading 31 



Inclusion of unmarked fish with abnormal fins 31 



Relation of disagreements to appearance of fin 31 



Relation of disagreements to year and locality of capture 32 



Relation of disagreements to size of fish 33 



Conclusions as to dependability of scale readings 35 



Growth of marked lake trout 36 



Length-weight relation 36 



Growth in length 3i) 



Lengths at capture 3(1 



Calculated lengths 40 



Factors of discrepancies in estimates of growth 42 



Growth in weight 48 



Weights at capture 49 



Calculated weights 49 



Progress of season's growth in length 50 



Summary 56 



Literature cited 58 



714::^ 



