LIFE HISTORY OF LAKE HERRING OP LAKE HURON 309 



The author conchides that body and scale growth are closely correlated, the 

 discrepancies being due to the fact that the measurements of the live cod arc subject 

 to "considerable inaccuracy." 



Storrow (191G) brought into the laboratory a young Ballan wrasse (Labrns 

 bergylta), 2 to 3 centimeters long, taken from a rock pool at Cullercoats m August, 1914. 

 On May 24, 1916, the fish had attained a length of 8 centimeters and completed two 

 summers' growth. According to calculations from its scales, the specimen had 

 attained a length of 3.7 centimeters at the end of the first year. This measurement 

 agrees fairly well with the observed length when it is remembered that the latter 

 value represented an incomplete growth year. On May 24 no new growth increment 

 had yet appeared on the scales nor had any body growth taken place since the previous 

 January. 



In April and May, 1915, several carloads of hatchery reared chmook-saimon fry 

 were planted in a small artificial lake near Seufert, Oreg. Rich (1920) measured a 

 small series of these fiy at the time of planting. The average length was 44.6 

 millimeters. On September 2, 1915, 55 of these salmon were recaptured. Their 

 average length had increased to 80.9 millimeters. Rich found that the sudden 

 change in their growth rate left a primary check on the scales. This enabled him 

 to compute from the scales the length of the fry at the time of the plant. His average 

 estimated length of 47.9 millimeters corresponded very closely with the actual 

 observed length at the time of planting. 



Snyder (1923) computed the lengths fi'om the scales of eight salmon marked 

 and liberated as fry and recaptured in their fourth year of life. The calculated 

 lengths indicated that the fish averaged 7.9 centimeters in length at the time of their 

 liberation and 55 centimeters at the end of their third year of life. These estimated 

 lengths compare favorably with the actual, which were found to be 8.5 centimeters for 

 100 fry and 55 centimeters for 50 marked fish recaptured in their third year of life. 



H. Thompson (1926) found that haddock formed a sharp "false ring" when 

 transferred from the sea to the aquarium. By means of this accessory check he was 

 able to compute, from the scales, the length of the fish when introduced into the tanks. 

 Employing scales of 1-year fish he estimated that these haddock averaged 13.7 

 centimeters in length at the time of transference, which value was 0.2 centimeters too 

 high and thus involved an error of less than 2 per cent. Thompson also presented 

 direct evidence that the first zone of haddock scales did not compress when additional 

 material was laid down. Lengths calculated back to the end of the first year varied 

 as follows: 10 fish gave accurate results, 2 gave results that were slightly too low, 

 and 12 gave values that were from 0.5 to 3 centimeters too high. The author ex- 

 plained the high values on the assumption that some of the haddock were so poor 

 at the end of each year that their scales were absorbed slightly. The experiments 

 showed that for the first three years, at least, the size of haddock scales increased 

 on the average in proportion to that of the fish. 



Creaser (1926) gives a table showing, for one blue gill {Heliox>erca incisor), the 

 actual increase in length of scales taken from various parts of the body during an 

 increase of 10 millimeters in the length of a 57 millimeter yearling fish. He concludes 

 that "there is little deviation from the direct proportion (between body and scale 

 growth) during the short scale increment of about 0.2 millimeter." The increments 



