SCALE OBSERVATIONS OF THE SQUETEAGUE AND PIGKISH. 



315 



is constantly diminishing, indicating a more rapid growth of scales than of the body. 

 Hence, the proportionate distance apart of the several annuli does not represent the 

 correct proportion of growth of the fish. This is probably compensated for by the late 

 appearance of the scales (Vogt, 1845). The fish is from 3 to 4 cm. long before any scales 

 appear. That any error here is negligible is testified to by the close agreement of the 

 "calculated" and "measured" lengths. (Table 2.) After the fourth or fifth year, 

 growth probably takes place very slowly, although the writer's data on very old fish 

 ■ are too meager to afford definite conclusions. 



(3) Age at first spawning has been the subject of much conjecture. The opinion 

 seems to have prevailed generally, probably on account of the rapid growth during 



3 4 5 



Age in years 



Fig. 4. — Polygon showing the occ-urrencc of dmoscion regalis at different ages. 



the first year, that spawning takes place at the end of the first year. With the evidences 

 afforded by scales, the writer is not prepared to accept this conclusion, unless the annuli 

 represent spawnings and they occur every year of the life of the fish. There are two evi- 

 dences which lead to the conclusion that spawning takes place for the first time in the 

 third year : (o) The survival of 94.7 per cent of all fishes through three years. (See table 

 6.) As they increase in age and length after this point, their numbers decrease remark- 

 ably. (Text fig. 4.) (6) The relative activity, as indicated by the radii. (Tables.) 



