314 



BULLETIN OF THE BUREAU OF FISHERIES. 



60 



50 



40 



I 30 



LIFE HISTORY OF THE SQUETEAGUE (CYNOSCION REGALIS) AS INDICATED BY THE SCALES. 



Unlike the salmon, which spends a life of widely varying conditions, and which, 

 by its various markings, first attracted the attention of scale investigators to the possi- 

 bility of determining age by 

 this means, the squeteague 

 leaves only obscure evidences 

 of its life history on its scales. 

 .Since it spends its entire life 

 under fairly constant condi- 

 tions, the sculpturings on its 

 scales are rather uniform. 



Effort has been made to 

 determine: (i) The age of 

 the fish of average size; (2) 

 the rapidity of growth; (3) 

 the age at first spawning ; (4) 

 the maximum age and length ; 

 (5) winter habits. 



(i) The average length 

 of all the fish measured " is 

 32 cm.; of the 38 specimens 

 the age of which were com- 

 puted (see table 6 and text 

 fig. 4), 94.7 per cent survive 

 till the third year. 



(2) The rapidity of 

 growth during the first year of 

 the life of the fish is remark- 

 able. The average length of 

 the squeteague at the com- 

 pletion of its first year is 20 

 cm. It is very rare for a 

 fish to grow more during any 

 subsequent year than in the 

 first. (Text fig. 3.)'' How- 

 ever, there is here the possi- 

 bility of a slight error. In 

 fishes of 4 or 5 cm. in length 

 the scales do not overlap, but 

 must grew proportionately more rapidly than the body in order to do so. In addition 

 to this, it is also noted that the proportion of the exposed part to the unexposed part 



<i Including 382 fish measured by Hecht and Crozier and the 65 specimens represented in table 2, total of 447. It will be 

 noticed that there are very few one-year fish in the table. This accounts for the high average of total length, 38 cm., which 

 agrees well with the calculated length for the average age (4.1 yr.), which is in the fourth-year coliunn, 38.48. (Table i.) 



& Carl H. Eigenmann (Investigations into the histori' of the young squeteague: Bulletin, U. S. Fish Commission, vol. 

 XXI, 1901, p. 47) concludes from measurements that a fish may reach the adult length of 4cx> mm. in 7 months. It will be 

 noted that this is at wide variance with the conclusions in this paper based on e\ndences found on scales. It will also be noted 

 that some of Eigenmann 's measurements were made on young fish kept in an aquarium, while those of the larger fish were made 

 on fish taken at a later time, with apparently no means of determining age. 



20 



10 



12 3 4 5 6 7 



A^e in years 



Fig. 3. — Comparison of calculated and measured lengths. Continuous line, lengths 

 calculated from width bands on scales; broken line, length groups measured. 



Cynoscion regalis. (See table 3.) 



