The Cisco of the Deeper Water Lakes

of Northern Indiana.

BY WILLIAM I. LOWER, M. A.

The species treated in this review is a member of the great family, Salmonoda, which includes the Atlantic and Pacific Salmon, the whitefishes of the Great Lakes, and the Lake or Mackanaw trout. The cisco is of the genus Leucichthys, in which genus falls the Michigan herring (Leucichthys sisco huronius), common in Lake Huron and Lake Michigan.

DESCRIPTION.

The cisco is found in the deeper glacial lakes of northern Indiana and southern Wisconsin. These species are known to occur in Indiana in the following lakes: Lakes Tippecanoe, Barbee, Crooked, Shriner, Twin Lakes, James, Dallas, Royer, Long Lake, Lake of the Woods, and Little Balls Lake; and no doubt in several other lakes not herein reported.

Jordan, in 1875, applied to the cisco the name Argyrosomus sisco, but the current spelling "cisco" instead of "sisco" is now adopted, and the name Leucichthys is now applied instead of Argyrosomus.

The cisco is regular spindle shape in form, slightly elevated at the beginning of the dorsal fin. Lower jaw the longer. Mouth small. Scales thin but firm. Dorsals short, rather high. Adipose fin rather slender. Caudal deeply forked. The illustration herewith is from a photograph of a specimen weighing two pounds, taken from Lake of the Woods in Lagrange and Steuben counties. As a matter of fact each separate lake has it own variety, but after careful observations of types from several lakes, it must be concluded that no specific difference can be made out by which they can be separated.

The color is of a deep steel blue, becoming gradually paler below the lateral line where it changes to a silvery hue. The scales are dotted with black, with traces of lines along the rows of scales. The fins and the skin on the head are also punctate. A specimen taken from Royer Lake was green, shading to a rich golden hue on the sides. The shiner has frequently been mistaken for the cisco. The adipose fin and deep forked caudal easily distinguish the cisco from any other of our lake fishes, and there need be no confusion.

The following is a comparison of types which I have taken from three different lakes and of types reported by Jordan from Lake Tippecanoe :

Comparison of specimens of Leucichthys cisco, including average for five specimens from each of the first three lakes, and the description recorded by Jordan and Evermann of types from Lake Tippecanoe are as follows:

Specimens taken from Lake of the Woods ranged from 8 oz. to 15 oz., from McKlish Lake, 1 lb. 10 oz. to 2 lbs. 5 oz., from: Royer Lake 15 oz. to 1 lb. 1 oz.

There is no noticeable difference between the male and female except as the maturity of the eggs effect the depth of the female. There is, however, quite a variation in individuals in size, shape and color, regardless of sex. See illustrations.

LIFE HISTORY AND HABITS.

Various traditional ideas have existed in regard to the life and habits of the cisco. Formerly they were thought to spend most of their time in the Great Lakes, working through some underground

Showing Variation in Form of Ciscoes Taken from Lake of the Woods. Weight 12 Ounces Each.

channel to the deeper inland lakes for spawning, and then returning to the place from whence they came.

From observations and study during the years of 1909 to 1912, inclusive, we conclude that the cisco remain in the deep part of the lake, coming out to shallow water to spawn. The spawning time lasts for about two weeks, and falls in the last days of November and first days of December. At this time they come to the surface and make for shore, splashing as they go. During this season called the run, they generally move in shoals. At least one female and one male move side by side, depositing eggs and milt promiscuously as they go.

The eggs are slightly heavier than water and sink gently to the bottom. They are 2.5 mm. in diameter when laid and swell to 3 mm. soon after they are spawned. It is probable that the impregnated eggs begin to develop directly after fecundation, and continue through the winter months, and when the ice goes out in the spring the embryos hatch and the fry comes forth, as is the case of the whitefish of the Great Lakes. The cisco are very prolific. A specimen weighing 12 oz. contained approximately 23,000 eggs.

ADAPTATION TO ENVIRONMENT.

The cisco has adapted itself to the place in which it lives, according to the changes undergone since postglacial times. It is seemingly a delicate fish, although, if kept in a cool temperature, is capable of great endurance. It has been kept alive for hours, in the month of July, in a tub of melting ice water. A temperature of 60 degrees, Fahrenheit, or higher is fatal. The temperature of the water beneath a certain depth (which reaches about twenty feet in summer and is known as the Thermocline) remains almost constant, from 2 to 4 degrees, Centigrade, this being the temperature to which the cisco is best adapted. Its spindle shape makes it easy for this fish to dart about in the water in capturing food or in avoiding its enemies. The blue black causes it to be almost invisible from above, and the silvery sides and white ventral portion make it practically invisible from a side or lower view.

The cisco is able to occupy all parts of the lake during the