STURGEON. 
1061 
and the suspicion readily suggests itself that the Ame- 
rican fresh-water Sturgeon is a landlocked form of the 
common Sturgeon, and stands in the same relation to 
the latter as Salmo trutta to S. salar. 
Of the life and habits of the Sturgeon we possess 
but scanty information. Most of its existence is passed 
at the bottom, where it is beyond the reach of all cu- 
riosity. To judge by its behaviour in aquaria, it is a 
sluggish, though petulant creature; and it usually glides 
at a gentle pace over the bottom, shooting out and 
drawing in its mouth; but of a sudden, awaking, as it 
were, from its drowsy laziness, it darts through the 
water with the speed of an arrow. It is extremely 
tenacious of life, and in a cool place may be kept alive 
out of the water for twenty-four hours or even longer. 
“It seems a spiritless fish”, says Pennant®, “making 
no manner of resistance when entangled, but is drawn 
out of the water like a lifeless lump”. By the asser- 
tion of its great muscular strength, however, it some- 
times gives formidable proof that it is by no means 
insensible to danger and sufferings, and a blow dealt 
by the tail of a large Sturgeon is enough to fracture 
an arm or a leg. Besides it is far from always so in- 
different to its fate as to abandon itself to the toils 
without more ado. The fishermen frequently complain 
that it breaks loose from their nets. When the Stur- 
geons are found in rivers Avhich they have ascended in 
order to spawn, and when they are distressed by the 
pressure of the tumid generative organs, they are slug- 
gish from natural causes; but “in the sea, where they 
are sometimes stated to be sterile, they are evidently 
not ripe for the time being, being in a certain sense 
virgin, and consequently far more active. Herr Dec- 
ker lias communicated a proverb current among the 
Sturgeon-fishermen of the North Sea, which runs, Leap- 
ing Sturgeons and dancing girls are hard to hold fast" 1 '. 
The Sturgeon also resembles the Salmons in its habit, 
when migrating, of now and then flinging itself entirely 
out of the water. 
The Sturgeon feeds in the manner just described 
on the worms of the bottom, crustaceans ( Amphipoda ), 
and mollusks, but also, like several Cyprinoids, on the 
decomposing animal substances to be found in the mud. 
The stomach of a male which was taken at Dalaro on 
the 18th of July, 1890, and which is represented in 
our figure (Plate XL VI, fig. 1), was filled at the an- 
terior crook with a score or two of Isopods (. Idothea 
entomon). That the diet of the Sturgeon consists prin- 
cipally of Herring, Mackerel, Cod, and Salmon, the last 
of which it chases up the rivers, is a statement which 
originated with Lacepede c , and was dictated by his 
conception of the Sturgeon as distinctly a predatory 
fish, using its barbels as a lure to entice its prey. The 
Sturgeon, no doubt, does not disdain a fish or two, 
when it can procure a meal of this kind — its larger 
congener, the Hausen, is notorious for its pursuit of 
small fishes, especially a variety of Bleak, in the Rus- 
sian rivers — but so far as we know, it contents itself 
with victims of insignificant size, such as Sand-Eels, 
whose manner of life renders them a suitable prey. We 
also know** that it is sometimes taken on Haddock-lines 
or Cod-lines, the bait of which must thus have attrac- 
tions for it. From the last-mentioned circumstance we 
may also conclude that its haunts in the sea extend from 
the littoral zone down to a depth of some twenty-five 
fathoms; but how deep it can descend, is unknown to us. 
The spawning-season of the Sturgeon occurs in 
spring and early summer, from April to the end of 
July. Like the Salmons, it then repairs to running 
water, preferring rivers with wide mouths, deltaic 
streams, or estuaries where the salinity of the water 
gradually diminishes up the channel. That it spawns in 
Sweden, admits of no question, though no special lo- 
cality where the operation takes place is known. In 
the middle of July we once received from Lulea a ripe 
male, the internal organs of which are described above, 
and at the same time of year we obtained a spent male 
from Dalaro. In the island-belt of Soderuianland Ek- 
strom secured fry 3 — 4 dm. long, “during autumn, in 
the deeper watercourses”. Under ordinary circumstances 
the Sturgeon does not ascend so far up the' rivers as 
the Salmon. Its timidity too probably leads it to avoid 
the Swedish rivers where timber is rafted. That it 
should spawn at the mouths of the Swedish rivers or 
even in the Gulf of Bothnia, on the shores of the island- 
belt, is by no means incredible. Milner describes how 
its nearly related congener, if not a member of the 
same species, the fresh-water Sturgeon of . America, 
" Brit. Zool. (1776), vol. Ill, p. 110. 
b Henking, Deutsch. Fisch. Ver., Mitth. Sect. Kiist., Hochseefisch., 1893, p. 21. 
c Hist. Nat. Poiss., (1798), tome I, p. 418. 
d Krgyer, 1. c., p. 775. 
