AGE AND GROWTH OF THE CISCO 
213 
the water. This factor was considered to be a fair index of the general productive 
capacity of the various waters. Size and form of basin were also taken into account 
in the selection of the lakes. Trout Lake is the second largest and the deepest lake 
of the region. In comparison with the surrounding bodies its water is relatively 
hard. Muskellunge is a lake intermediate as to size and as to the amount of fixed 
C0 2 . Silver Lake is a small lake with intermediate conditions with respect to fixed 
C0 2 . Clear Lake has an area approximately equal to that of Muskellunge Lake. Its 
water contains an unusually small amount of fixed C0 2 . 
Table 1 gives for each lake the details of location, area, depth, and also data 
relative to the physical and chemical nature of the waters. The two lakes, Allequash 
and Tomahawk, from which small samples of scales were obtained for growth study, 
are included in the table. 
Table 1 . — Description of the 6 lakes of which cisco populations were studied 
[The characteristics, color, pH, conductivity, fixed CO 2 , and organic content of plankton refer to average surface conditions. These 
data were furnished by the Wisconsin Geological and Natural History Survey] 
Lake 
Location 
Length in kilo* 
meters 
Width in kilo- 
meters 
Surface area (hec- 
tares) 
Maximum depth 
(meters) 
Volume in 1,000 
cubic meters 
Secchi disk trans- 
parency (meters) 
Color platinum 
cobalt scale 
M 
a 
Conductivity in 
reciprocal meg- 
ohms 
Bound CO 2 in 
milligrams per 
litre 
Organic matter of 
plankton in mil- 
ligrams per litre |. 
Town 39N, range VI IE 
2. 10 
1. 83 
373 
26.5 
6.3 
0 
6.6 
17 
2. 2 
0. 84 
Muskellunge 
Town 41E, range VIIE 
3. 30 
1. 18 
375 
19.3 
26, 172 
9, 884 
4.0 
4 
7.3 
40 
10.0 
1. 16 
Silver I 
Trout: 
Town 41N, range VIE 
1. 69 
.64 
87.3 
19.5 
5.5 
4 
7.5 
62 
15.0 
.85 
North basin 
/Town 41 and 42N, range VI 
\ and VIIE. 
/ 3. f>0 
\ 4.51 
2. 10 
532 
29.0 
69,017 
5.0 
6 
7.8 
73 
18.5 
.66 
South basin 
3. 86 
1,051 
35.5 
149, 020 
4. 5 
3 
7.6 
77 
18.7 
.92 
Allequash___ 
Town 41N, range VIIE 
2. 41 
1. 41 
142 
7. 5 
1. 5 
30 
7. 9 
67 
16. 9 
1. 48 
Tomahawk 
Town 38 and 39N, range VI 
and VIIE. 
7.24 
3.00 
1, 476 
22.5 
4.2 
8 
7.6 
69 
16.7 
.78 
'All ciscoes collected from Trout Lake were taken in the south basin. 
Juday and Birge (1930) published a general description of the northeastern 
highland lake district. Thwaites (1929) described the glacial geology of a part of 
Vilas County in which all but two (Clear Lake and Tomahawk Lake) of these lakes 
are located. Chemical, physical, and biological data concerning the various lakes 
have appeared from time to time in the publications of the limnological laboratory 
of the survey. 
From time to time in the following discussion different species of fish will be 
mentioned by their common names. Because of the considerable local variation in 
the common names of fishes it is thought well to list the scientific names of the various 
species mentioned, along with their common names: 
Bluegill, Helioperca incisor (Cuvier and Valen- 
ciennes). 
Burbot, Lota maculosa Le Sueur. 
Ciscoes or chubs, Leucichtliys spp. 
Cisco, lake herring, Leucichtliys artedi (Le Sueur). 
Lake trout, Cristivomer namaycush (Walbaum). 
Largemouth black bass, Aplites salmoides (La- 
c6pede). 
Perch, yellow perch, Perea flavescens Mitchill. 
Pike-perch, Stizostedion vilreum (Mitchill). 
Rock bass, Ambloplites rupeslris Rafinesque. 
Sauger, Stizostedion canadense (Smith). 
Smallmouth black bass, Micropterus dolomieu 
Lac6p£de. 
Sucker, Catostomus commersonnii (Lacepede). 
Whitefish. Coregonus clupeaformis (Mitchill). 
