8 THE AGE AND GKOWTH OF SALMON AND TEOUT. 



corresponded exactly with the known life of the fish. Those recaptured 

 as grilse in 1906 had two summer-zones and one winter-band formed subse- 

 quently to migration, whereas the scales from fish recaught in 1907 had 

 two summer-zones and two winter-bands when caught in the spring, and 

 an additional summer-zone when caught later on in the year. 



I have found identical summer-zones and winter-bands on the scales of 

 Norwegian salmon, and I have also discovered that according to the size of 

 the fish they may show from one to four winter-bands subsequent to 

 migration. 



It was therefore of great interest to investigate the scales of the small 

 grilse which are frequently caught in the mackerel nets in the Skagerack. 

 These fish varied in size in May and June from 36 cm. to about 45 cm., and 

 the scales show that all these fish have spent one summer, one winter, and 

 part of a second summer in salt water. 



It was even of greater interest to discover salmon in a less advanced 

 stage of growth in the Sandeid Fjord in Eyfylke, and which were sent me 

 by Herr Landmark, the inspector of fisheries. The examples sent consisted 

 of nineteen individuals, varying in length between 22 cm. and 27 cm., and 

 were caught between July 28 and August 28 in 1908. Their scales showed 

 markings similar to the one illustrated in Fig. 8 (Plate I.), which was photo- 

 graphed from the scale of a fish 26 cm. in length. In the centre is clearly 

 shown the poor growth made in the river prior to migration, but 

 surrounding this we find a zone of wide and well-marked rings, without any 

 branching or contraction in their formation. 



If, however, we compare Fig. 9 (Plate II.), which represents the scale of 

 an ordinary grilse 57 cm. long and weighing 1*9 kilos, we find that it has 

 two summer zones and one winter band subsequent to migration. Further, 

 if we compare Fig. 10 (Plate III.), which is similarly reproduced from the 

 scale of a salmon 76 cm. in length and 4*3 kilos, in weight, we find two 

 winter-bands and three summer-zones after migration. Fig. 11 (Plate IV.) 

 represents the scale of a salmon of 10'5 kilos, and 96 cm. long, and here 

 we find after migration three summer-zones, three winter-bands and the 

 commencement of a fourth summer-zone at the edge of the scale. Finally, 

 in Fig. 12 (Plate I.), which depicts the scale of one of the largest salmon I 

 have been able to get hold of, we find surrounding the central portion of the 

 scale, which indicates the life of the fish up to the smolt stage, four, and 

 possibly five, winter-bands with the corresponding summer-zones. Now if 

 we compare Figs. 9, 10, and 11 we easily perceive that in 9, which was 

 caught on July 8, in the Topdalsfjord, the winter-band is some distance 

 from the edge of the scale, whereas in 10, which was caught in the same 

 place, but on May 27, the last winter-band lies much closer to the edge. 

 In 11, which was caught on June 9 in Finmarken, where summer begins 



