8 FISHES OF PENNSYLVANIA. 
Reproduction.—Spawning takes place in the Delaware during May. 
The eggs are deposited in depths of one to five fathoms on hard bottom 
in brackish or nearly fresh water. Prof. Ryder states that the eggs are 
extruded by rubbing the belly either against hard places on the river bed 
or against the rough bodies of the males, two or more of which accom- 
pany each female. The gravid roe fish are larger than the males. 
Prof. Ryder found the ova more or less adhesive immediately after their 
removal from the abdomen, but the sticky mucus covering is soluble in 
water. The period of hatching varies from four to six days. 
Focd.—Up to the third month of its life the young sturgeon has min- 
ute conical teeth in its jaws and at this age itis believed to subsist upon 
“rhizopods, unicellular algze, infusoria, minute larve of insects and 
worms, crustaceans, ete.” Stili following the observations of Prof. Ryder, 
we learn that the sturgeon, when it has reached alength of one inch to 
one and a half inches, has minute teeth on the floor of the pharynx and 
feeds upon small water fleas, and probably algze, worms, embryo fishes, 
insects and fresh water copepods. Later in life the fish seeks larger 
crustaceans and the adults occasionally contain fragments of mussel 
shells. The young fish have been caught under the ice in midwinter 
and are known to pass most of the year in fresh water. 
8. Acipenser rubicundus Lez Svevr. 
The Lake Sturgeon. (Figure 20.) 
The body of the lake sturgeon is rather slenderer than that of the common stur- 
geon. Thesnout is somewhat blunt; inthe younglongandslender. The shields of 
the body are large, about fourteen on the back, thirty or more on the side, and eight or 
nine along the abdomea, between pectoral and ventral fins. Each shield is sur- 
mounted by a strong hooked spine. The head is contained three and one-third 
times in the length without tail. Barbels four, rather long. Eye small. Dorsal 
and anal fins small, placed far back asin the pike. D. 35; A. 26. 
This is known as the lake sturgeon, Ohio river sturgeon, rock stur- 
geon, bony sturgeon, red sturgeon and ruddy sturgeon. Itinhabits the 
Mississippi and Ohio rivers and the Great Lakes, and is abundant in the 
Allegheny. From the lakes it ascends the streams in spring for the 
purpose of spawning. Dr. Richardson states the northern limit of the 
sturgeon in North America to be about the fifty-fifth parallel of latitude. 
Size.—The lake sturgeon is smaller than the common marine stur- 
geon, the average adult being less than five feet in length. The average 
weight of 14,000 mature sturgeon taken at Sandusky, Ohio, was about 
fifty pounds. It frequently reaches a length of six feet. 
In the lakes the species, according to observations of James W. Mil- 
ner, inhabits comparatively shoal waters. 
The food of this sturgeon is made up chiefly of shell-fish, including 
the genera Limnea, Melantho, Physa, Planorbis and Valvata. LKggs of 
fishes are also to be found in their stomachs. 
