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Becker, George C. / Fishes of Wisconsin
(1983)

Perch family - percidae,   pp. 869-954 PDF (42.5 MB)


Page 954

 
954   Perch Family-Percidae 
Age     No. of 
Class   Fish 
    TL 
    (Mm) 
Avg  Range 
Calculated TL 
at Annulus 
   (mm) 
 1      2 
I        38         35.00 28-41        31.21 
II        1         38.00              30.00 38.00 
Avg (weighted)                         31.18 38.00 
first spawning. Of the museum    specimens exam- 
ined, only three had reached age II. They were 35-38 
mm long, and the second annulus was at the margin 
of the scale. The length-weight relationship for least 
darters, based on 252 fish, was Log W = - 11.7308 
+ 2.9805 Log L (Lutterbie 1976), where W is weight 
in grams and L is total length in millimeters. 
  The least darter reaches sexual maturity at a length 
of 27 mm at age I (Lagler et al. 1977). All age-I least 
darters are mature. It is the smallest of Wisconsin 
fishes in length, and among the earliest to mature. A 
large least darter (UWSP 3816) is an age-I specimen, 
41 mm (1.6 in) TL, and 0.5 g. It was taken from the 
Crystal River (Waupaca County) in 1971. Trautman 
(1957) reported a specimen 46 mm (1.8 in) long. 
  The least darter feeds on all sorts of minute aquatic 
animal life. The stomachs of least darters taken from 
a pond adjacent to the Plover River (Portage County) 
contained large quantities of copepods and cladocer- 
ans (V. Starostka, pers. comm.). All food was of ani- 
mal origin; no vegetation or sand appeared in any of 
the digestive tracts examined. In another sample 
from the same locale, the stomachs contained clado- 
cerans, Diptera larvae, and unidentified plant seeds 
(A. Kossel, pers. comm.). Starostka noted that fall 
specimens had fat deposits on the viscera; the fat was 
absent in spring specimens, suggesting that fat was 
used for winter survival. In southeastern Wisconsin, 
the least darter's food consisted of about equal 
amounts of insect larvae, nymphs, and entomostra- 
cans (Cahn 1927). 
  The least darter is an inhabitant of cool to warm 
waters. In Canada, it was associated with the rock 
bass and smallmouth bass at an average summer 
water temperature of 21'C (70*F); it avoided the 16- 
17'C (60-62°F) temperature range inhabited by the 
brook trout and the mottled sculpin (Hallam 1959). 
  After the spawning period, the least darter moves 
back into deeper waters. In Whitmore Lake, Michi- 
gan, this species was found in the thick organic de- 
bris and plant zone in 1.2 m of water (Winn 1958). In 
the shallow periphery of a large pool below the Crystal 
tal River Dam (Waupaca County) I found numbers of 
least darters in cavities hollowed out under large 
stones, which provide a natural form of cover in the 
absence of vegetation. 
  In the Allenton Flowage (Washington County), 10 
least darters were collected with the common carp (1), 
creek chub (13), northern redbelly dace (1), black 
bullhead (2), tadpole madtom (3), green sunfish (2), 
pumpkinseed (1), rock bass (1), and central mud- 
minnow (+). 
  In an Illinois study (Burr and Page 1979) the great- 
est density was 33.09 least darters/m2 collected in 
mid-October; the least density, 0.84 darters/M2 in late 
March. During winter months the density decreased, 
and few individuals in the 1 + year class survived. 
  In an Ohio study of stream dessication, Tramer 
(1977) found that the least darter survived periods of 
drought by burrowing into the substrate. When rain 
refilled dry pools in the creek, the least darter reap- 
peared. 
IMPORTANCE AND MANAGEMENT 
Little is known about the significance of the least 
darter in the food chain of other fishes. The black 
crappie and largemouth bass have fed on it to some 
extent (Cahn 1927). Petravicz (1936) indicated that 
supernumerary least darter males may devour eggs 
fertilized by rival males. Its close association with 
dense vegetation undoubtedly affords it considerable 
protection from predators, and perpetuates its secre- 
tive habits. 


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