8 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 3. — Extent of regeneration of the pectoral fins,, expressed as number of rays, on lake trout marked in 1945 and 1946 



Locality of recovery and mark; year of planting 



offish 



Number of rays regenerated 



>8 



Unknown 



Areas 1-6: 



Eight pectoral (1945) 



Percenta?e ' -_ 



Left pectoral (1946) 



Percentage 



Ritiht and left pectorals 

 Percentage 



Area 8: 



Right pectoral (1945).,.. 



Percentage 



Left iiectora! (1946) 



Percentage 



Right and left pectorals. 

 Percentage 



271 

 i.348 



679 



65.0 



96 



36.8 



774 

 57.5 



91 



8.7 

 29 

 11.2 

 120 

 9.2 



46 



4.5 



9 



3.5 



55 

 4.2 



43 

 "69" 



"in2 



1 

 2.4 



1 

 1.4 



31 

 3.0 



10 

 3.9 



41 

 3.1 



1 

 3.0 



2.4 

 2 



2.7 



36 

 3.4 



10 

 3.9 



46 

 3.5 



48 

 4.6 



13 

 5.0 



61 

 4.7 



3 

 9.1 



3 



4.1 



30 

 2.9 



17 

 6.6 



47 

 3.6 



1 

 3.0 



2 

 4.9 



3 

 4.1 



25 

 2.4 



14 

 5.4 



39 

 3.0 



1 

 3.0 



1 

 1.4 



17 

 1.6 

 28 

 10.9 

 45 

 3.5 



2 

 6.1 



2 

 4.9 



4 

 5.4 



41 



3.9 



33 



12.8 

 74 

 5.7 



26 

 7.5.8 



35 

 85.4 



60 

 81.1 



I Fish with unknown number of fin rays not included in percentages. 



Table 4, — Extent of regeneration of the perioral fins, expressed {for most fish) as a fraction of the normal length of the fin, on 



lake trout marked in 194-5 and 1946 



Locality of reco\ery and mark; year of planting 



Number 

 of fish 



Extent of regeneration 



No 



regener- 

 ation 



Less 



than 



t/ij-inch 



long 



normal 

 length 



normal 

 length 



normal 

 length 



Full 

 normal 

 length 



No 



record of 



length 



Areas 1-6; 



Right pectoral (194.6) 



Percentage ' 



Left pectoral (1946) 



Percentage 



Right and left pectorals. 

 Percentage 



Area S: 



Right pectoral (1946)..-. 



Percentage 



Loft i)ectoral (1946) 



Percentage 



Right and left pectorals. 

 Percentage 



1.077 



27! 



V.iis 



679 



63.8 



95 



36. 



774 

 58.2 



43 

 "59' 

 162" 



1 

 2.0 



124 



11.6 



48 



18.2 



172 



12.9 



1 

 2.6 



2 

 3.9 



3 

 3.4 



18 

 1.7 



2,7 

 26 

 1.9 



1 

 2.6 



4 

 7.8 



6 

 5.6 



21 



2.0 



8 



3.0 



29 



2.2 



2 

 5.3 



1 

 2.0 



3 

 3.4 



128 



12.0 



60 



22.7 



188 

 14. 1 



15 

 39.5 



IS 

 35.3 



33 

 37.1 



0.8 

 2 



(1.8 



10 



U. S 



1 

 2.0 



1 

 1.0 



1 Fish with fins of unknown length not included in percentages. 



though this percentage was somowliat higher than 

 would be expected from an assumption of complete 

 iiulcpeiulcnce of age shown by abnormal fins and 

 by scale markings, it does indicate that if the 

 sample from area 8 contained any authentic 

 marked lake trout, their number was extremely 

 small. 

 GROWTH AS INDICATED BY ABNORMAL FINS 



Presentation here of details on length frequen- 

 cies and average sizes of various age groups of the 

 different year classes as established by abnormali- 

 ties of the fins and by the examination of the 

 scales would be little to the point as the situation 

 is described adequately by the data of table 5 

 which shows the mean lengths and ranges of 

 length for the several age groups (year classes 

 combined) as indicated by fins. If these lake 

 trout are taken as bona fide fin-clipped fish, we 

 must accept also tlie conclusion that the trout 

 were largest in the first and second years of life 

 (average lengths of age-groups I and II, 23.8 and 



17.1 inches, respectively), were smaller, and, for 

 the most part, without growth in later years 

 (range of 12.5 to 12.7 inches for average lengtlis 

 of age-groups III-VI, and only 13.7 inches for 

 age-group VII)." Despite the consiilerable range 

 of length for each age group of lake trout of known 



Tablk .5. — Average lengths and ranges in length iif age 

 groups as indicated by the occurrence of abnormal fins 

 '{assumed to be true marks) of lake trout from southern 

 Lake Michigan 



[See text discussion of the probability that few or none of these fisti c luld have 

 come from the various fin-elipping e.vperiments] 



'" According to Smith and Van Oosten (1940) lake trout tagged at Port 

 Washington, Wis., that averaged 12.8 inches long at tagging were 19.8 indies 

 long about 2 years later. 



