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Becker, George C. / Fishes of Wisconsin

Bullhead catfish family - ictaluridae,   pp. 693-732 PDF (19.6 MB)

Page 729

Flathead Catfish  729 
  Pylodictis olivaris            T 
ated by swirling currents. Cross (1967) found: "Many 
such pools now exist below concrete aprons of low 
dams, and adjacent to bridge-supports that trap 
driftwood. Such obstructions in the channel disrupt 
the streaming flow of the current, leaving deep 
pockets in the otherwise shallow beds ... " The flat- 
head catfish prefers tangled timber, piles of drift, or 
other cover. 
The spawning of the flathead catfish takes place in 
June and July in secluded shelters and dark places. 
Spawning occurs at water temperatures of 22.2-23.9°C 
(72-75°F). A large nest is built. Cross (1967) reported 
finding a bank nest that had been dug into a steep 
clay bank with an entrance about 355 mm (14 in) diam, 
which widened to 813 mm (32 in) inside the nest 
chamber. The bottom of the nest was silt free, and 
there was a ridge of clean gravel at the entrance. 
  Nest construction was observed at the Shedd 
Aquarium, Chicago (W Chute in Breder and Rosen 
                  Range of the flathead catfish 
                  0 Specimens examined 
                  J  Wisconsin Fish Distribution Study (1974-75) 
                  o Literature and reports 
                  o Greene (1935) 
1966). Both male and female (about 1.2 m long) used 
their tails and mouths to make a hollow in the sand 
down to the bare gravel and rock in one corner of 
the tank; the completed nest was approximately 1.5 
m diam. 
  Spawning was witnessed in the Dallas Aquarium 
(Fontaine 1944:50-51): 
  As breeding approached the male was often seen with 
the female, swimming over and beside her, gently rubbing 
his belly on her back and sides. His barbels apparently had 
some effect as they were brought into play almost con- 
stantly as he rubbed her. There was no apparent change in 
color during spawning, such as has been observed in many 
other species of fish. Presently the male came to rest on 
the bottom with his caudal peduncle and caudal fin encir- 
cling the head of the female. There was then a strong quiv- 
ering movement on the part of the male. This was re- 
peated from time to time and was observed at irregular 
intervals for almost two weeks. When the female was ready 
to spawn she began to deposit her eggs in a depression in 
the gravel that she and the male had prepared, behind an 
old tree stump on the ledge to the rear of the tank. The 
female expelled the eggs in masses of 30 to 50 which were 

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