Page 702

702   Bullhead Catfish Family-Ictaluridae 
Brown Bullhead 
Ictalurus nebulosus (Lesueur). Ictalurus-fish cat; neb- 
     ulosus-clouded, in reference to mottled color- 
     ing. 
Other common names: northern brown bullhead, 
     marbled bullhead, marble cat, speckled bull- 
     head, speckled cat, common bullhead, bull- 
     head, brown catfish, common catfish, small cat- 
     fish, catfish, mudcat, red cat, horned pout, 
     bullpout. 
Adult 275 mm, Half Moon L. (Eau Claire Co.), mid-Apr. 1978 
DESCRIPTION 
Body robust, rounded anteriorly, compressed poste- 
riorly Length 152-254 mm (6-10 in). TL = 1.20 SL. 
Depth into TL 3.8-5.7. Head length into TL 3.8-4.4. 
Snout bluntly pointed in lateral view, broadly rounded 
in dorsal view; elongated barbels of snout just ante- 
rior to posterior nostrils. Mouth short but wide, ter- 
minal and horizontal; upper jaw slightly longer than 
lower jaw, with very long barbel sweeping poste- 
riorly from the upper jaw at each corner of the 
mouth; 4 barbels (outer 2 much elongated, inner 2 
thinner and shorter) attached in a transverse line on 
the lower chin; numerous small, sharp teeth ar- 
ranged in several irregular rows on upper and lower 
jaws. Dorsal fin origin at about midpoint between 
pectoral and pelvic fins; dorsal fin with a stout spine 
and 6-7 soft rays; dorsal adipose fin free at posterior 
edge. Anal fin rays, including rudimentaries, 21-24; 
pelvic fin rays 8. Pectoral fin with an elongated spine 
barbed on posterior edge, near tip with barbs in- 
clined toward the base of spine, barbs becoming erect 
near middle, and barbs inclined toward the tip near 
base (see Key, p. 146). Caudal fin edge straight, oc- 
casionally slightly indented at middle. Scaleless. Lat- 
eral line complete. Digestive tract coiled, 1.1-1.4 TL. 
Chromosomes 2n = 60 (LeGrande 1978). 
  Dorsal region of head, back, and upper sides yel- 
lowish brown to almost black; lower sides mottled 
with lighter yellowish brown to gray; ventral region 
of head and belly pale yellow to white. Barbels dark 
brown to nearly black, except sometimes barbels on 
chin yellow to white. All fins dark colored, similar to 
body; interradial membranes slightly darker, but not 
black. 
  Hybrids: Brown bullhead x black bullhead from 
Lost Lake and Crawfish River (Dodge County) (Wis. 
Fish Distrib. Study 1974-75). Experimental brown 
bullhead x yellow bullhead, brown bullhead x blue 
catfish, brown bullhead x white catfish, brown bull- 
head x channel catfish (Dupree et al. 1966). 
SYSTEMATIC NOTES 
Two subspecies are recognized; Ictalurus n. nebulosus 
(Lesueur) is found in Canada, the Dakotas, Wiscon- 
sin, and the northern part of the Ohio Valley to Vir- 
ginia; this form has been extensively introduced into 
western North America. Ictalurus n. marmoratus ranges 
from southern Illinois and northeastern Oklahoma to 
the Carolinas and Florida. 
DISTRIBUTION, STATUS, AND HABITAT 
In Wisconsin, the brown bullhead occurs in the Mis- 
sissippi River, Lake Michigan, and Lake Superior 
drainage basins. Its major distribution is in the Rock 
and Fox-Wolf River systems of eastern Wisconsin, 
and the Chippewa River system of northwestern 
Wisconsin. It is present in the shallows of Lake Su- 
perior, Lake Michigan, and Green Bay, and in the 
lower courses of tributary streams. Although the 
brown bullhead has been reported frequently from a 
number of sources, some of these reports may be in 
error since this species is easily confused with other 
species of bullheads. I have plotted these reports on 
the distribution map when there was no opportunity 
to check them. As an example, I have not personally 
seen a specimen of the brown bullhead from the Wis- 
consin River basin, although it is commonly reported 
from that system. 
  According to McLain et al. (1965), the brown bull- 
head is widespread in the mouths of tributaries to 
Lake Superior; in these waters its numbers fluctuate 
widely from year to year, but the trend is toward in- 
creasing numbers. Priegel (1967) described the brown 
bullhead as abundant in Lake Winnebago. In gen- 
eral, its distribution over Wisconsin is sporadic and 
its numbers are low. It is the least common of the 
state's three species of bullheads, and its status has 
probably changed little since the 1920s. 
  The brown bullhead inhabits the weedy waters of 
warmwater lakes and sluggish streams. In the Mis- 
sissippi River it occurs in sloughs and backwaters. It