SCALE OBSERVATIONS OF THE SQUETEAGUE AND PIGFISH. 



321 



The method of determining the probable length of life and spawning time of the 

 pigfish was the same as that pursued for the squeteague. The survival of the great 

 majority of pigfish through two years, followed by a sudden and great diminution in 

 number, suggests the conclusion arrived at by Gilbert (191 3) for the Pacific coast salmon, 

 i. e., that this is the age of sexual maturity and that as a general rule they perish after 

 this time. A glance at text figure 6 shows that out of 167 fish observed, only one reached 

 the fourth year; 17 reached the third year, while 75 and 74 reached the ages of i and 



20 

 19 

 18 

 17 

 16 

 15 

 14 

 13 

 ^ 12 



s 



.1 11 



I 10 



I « 

 I 7 



8 9 10 11 12 13 14 15 16 17 13 19 20 21 22 23 24 25 25 27 28 



Length in cm. 



Fig. 7.— Occurrence of pigfish of one, two. and three years old. OA, fishes one year old; PB, two 

 years; NC, three years. The 8 cm. class consists of specimens 8 to 9 cm. long, etc. 



2 years, respectively. At all events, if the pigfish ever lives over four years it is 

 extremely exceptional, since out of the total of 337 fish examined only one was found 

 of that age, and none exceeded it. (Text figure 8.) Reasoning then from the small num- 

 ber of fish upon which perpetuation of the species would depend if spawning did not 

 take place before the fourth or third year, we are forced to the assumption that the 

 pigfish spawns in the second year if not in the first. There is no evidence on the scales 

 to indicate whether or not spawning occurs in the first year, unless we regard the almost 

 universal survival through the second year and the unripe condition of the ovaries and 

 testes in July in i -year-old fish as evidence that spawning does not occur the first year. 



