SMELT. 
873 
indicates at least no lack of agility. But out of the 
water it soon dies, no more tenacious of life than the 
Herring. It is a migratory fish like the Salmons, though 
not in so high a degree, roving at the spawning-season 
from salt water to fresh, or, in the lakes, from deep 
water to the shallows. As the spawning-season ap- 
proaches, it assembles in large and dense shoals; but at 
other times it leads a more solitary life, being fre- 
quently taken in the Herring-nets used in the Baltic, 
but not in any great number. It feeds principally on 
fish, small or large — at least up to half of its own 
size — and especially on Herring-fry and the young of 
its own species. Other kinds of food, however, such 
as crustaceans (shrimps and Gammaroids), worms, and 
larva?, do not come amiss. 
According to Yarrell the marine Smelt of the 
English coasts repairs to fresh or brackish water, and 
remains there from August to May. In the Norrstrom 
off Stockholm a female 196 mm. long and a male 188 
mm. long, both quite ready to spawn, were taken on 
the 4th of November, 1892; but as a rule the Smelt 
does not muster in Sweden for its breeding expeditions 
until the end of March or even later. From the island- 
belt of Sodermanland Ekstrom wrote, “In March or 
April, according to the earlier or later breaking up of 
the ice, the Smelt ascends to rivers, straits, or shores 
where there is some current, always choosing, however, 
water of some depth with a clean, sandy bottom. It 
generally -rises' towards evening and continues its jour- 
ney the whole night, but at daybreak again retires for 
the most part to deep water. A remarkable circum- 
stance is that, whereas all other fishes prefer to spawn 
in fine weather, in the Smelt the case is just the re- 
verse. In squally and snowy weather it is most eager 
in its ascent, the violent gusts of wind and snow that 
occur during the said months being hence known as 
nors-il (Smelt squalls). Males and females swim in 
company during the spawning, and are so densely 
massed that they seem merely to rub their bodies to- 
gether in order to rid themselves of the roe, which is 
deposited on the bottom beneath.” The young start 
first, but do not ascend so far up the rivers as the 
older fish, and often spawn in the lakes on shallow 
shores. Each shoal completes its spawning operations 
iii a few days; but one shoal follows in the wake of 
another, and thus the spawning continues as a rule 
from the latter part of March to the first weeks of May. 
The greater part of the shoal is composed of females, 
and after the spawning the shore and the bottom are 
strewn with numbers of dead Smelts which have strug- 
gled in vain to disburden themselves of the roe". The 
ova are light yellow; their diameter was estimated by 
Benecke at 0'6 — 0'8 mm., and their number in a fe- 
male 18 — 20 cm. long by Norback at 50,000, by Olsen 
at about 36,000. They attach themselves in a singular 
manner to the objects on which they fall after impreg- 
nation. According to Cunningham b , the outer membrane 
of the ovum, the so-called zona radiata , “is differen- 
tiated into two layers, the outer of which is somewhat 
thinner than the internal. In the zona radiata externa 
the pores are larger and farther apart than in the in- 
terna. But the important fact, which I believe no one 
has previously observed, is that the external zona sepa- 
rates very readily from the internal, and, rupturing at 
one portion of the ovum, peels off, becoming turned 
inside out in the process, and, remaining attached over 
a small circular area., forms the suspensory membrane”, 
by means of which the ovum is attached to any ex- 
ternal object. 
The eggs are hatched, according to Blanchere, in 
8 — 10 days, according to Feddersen in 12 days, and 
according to Sundevall in 18 days, a discrepancy of 
observation which in all probability depends on the dif- 
ferent temperature of the water during the period of 
incubation. On their first exclusion the fry are elongated, 
according to Sundevall 5 mm. long, and perfectly trans- 
parent; they are characterized by the unusually back- 
ward position of the vitelline sac, the distance between 
it and the insertion of the pectoral fins being more than 
half of that between these fins and the tip of the snout. 
Ehrenbaum 0 gives some personal observations on the 
growth of the larval Smelts. In the first month after 
the hatching, according to him, they grew to a length 
of 14 — 18 mm.; in the second he found them to be 
27 — 34 mm. long, in the third 32 — 37 nun., in the 
fourth 35 — 44 mm., in the fifth 44 — 60 mm. Still, 
in August, according to Yarrell, they already measure 
as much as about 7 1 / 2 cm. The Smelt attains maturity 
in the following spring, or, according to Norback, 
even at a length of 43 — 60 mm. 
a Faith in Krdyer (1. c.) and Feddersen in the Tidslcr. f. Fiskeri, vol. IV (1870), p. 102. 
b Proc. Zool. Soc. Lond. 1 886, p. 292, tab. XXX. 
c Sonderbeil. Mittheil. Sekt. Kiist., Hochs. Fisch., Jalirg. 1892, p. 12. 
