LIFE HISTORY OF LAKE HERRING OP LAKE HURON 289 



absohit sicheres Merkmal fiir das Alter cincs Aalindividinims an Jahrcn kSniicn also 

 die Zmvachszonen der Sch\ii)peji jiicht dienen, was in anbetraeht des sehr unreg:el- 

 massigcu EntAncldungsgangos * * * zii erwarten war." Hornyold (1922) con- 

 cludes, similarly, that in the eel, scales fb'st appear not at a definite age but at a definite 

 size (6 inches) of the fish; and further, that the difi^erence between the number of 

 zones of the otolith and the scale varies during the life of the eel according to the 

 faster or slower development of the various zones of the scale. The differences 

 varied from 4 to 10, in general the greater discrepancies occurring in the larger eels. 

 In the j'ellow eels of the Sarthe, however, the author (Hornyold, 1926) finds much 

 smaller discrepancies between the otoliths and scales (difference of 2 or 3 zones), 

 which discrepancies do not increase with the age of the fish. Wundseh's (1916) 

 tables show that the otoliths of liis eels generally form three more zones than do the 

 scales, although the difl'erence in the number of zones varies from 2 to 6. Ehren- 

 baum (1912) believed that mackerel scales form during the second year of life, while 

 Meek (1916) stated that as the marine herring spawii in August the first winter 

 is not registered on their scales. According to Molander (1918), the spring her- 

 ring (marine) hatched in the spring and the winter herring hatched in late summer 

 or early fall (September) form an annulus in the first ■winter of life, but the autumn 

 herring hatched in October-November do not form an annulus imtil the second winter 

 of life. It is pos.sible that indi\aduals among the winter herring that hatch late do 

 not form a ring the first vrinter, while those among the autunm herring that hatch 

 early do form a first winter's ring. At any rate, the following condition generally 

 obtains: A 2-year-old spring hening has its second annulus at the margin of the scale, 

 a 2-year-old' winter herring has its second anmdus witliin a nearly completed summer 

 growth zone, and a 2-year-old autumn herring has one annulus and a completed 

 summer growth zone at the margin. 



Arwidsson (1910) studied a series (148 fish) of young salmon {Salino salar) 2 to 

 26 months of age and found (6) that the first annulus was completed in September 

 in a 62-millimeter fish 6 months old. In December, at the age of 9 months, several 

 other individuals greater than 60 millimeters in length completed the first annulus. 

 In May, the fourteenth month, none of the fish under 61 millimeters in length had 

 completed the first annulus, but by July all fish showed on their scales seven or more 

 circuli outside the first year mark. In September (eighteenth month) two individ- 

 uals had already formed 5 to 6 circuli outside the second annulus, while none of the 

 21 or 26 months old individuals had completed this year ring. The author con- 

 cludes that the first anmdus does not appear at a definite time nor at a definite age 

 but at a definite length of the fish — namely, 60 millimeters. 



Rich's (1920) results parallel somewhat those of Arwidsson. If 1 imderstand the 

 former correctly, it is possible for the Pacific chinook salmon to show, in the second 

 spring* of life, one, two, or three checks on their scales. The yearling fish, migrating 

 in the spring, may show a "primary check" in addition to a winter ring. Migrating 

 fry taken in the estuaries after May may show a "primary" and a "migratory" 

 check. Presumably the early migrants of such fry would, in addition, have formed 

 a winter ring in the sea. The three kinds of checks can not always be distinguished, 

 while in some instances the migratory check is the winter band (Rich, p. 49). The pri- 

 paary check (presumably always the first to form) may occur any time early in life; the 



