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Becker, George C. / Fishes of Wisconsin

Sucker family - catostomidae,   pp. 607-691 ff. PDF (39.5 MB)

Page 685

White Sucker   685 
completed by 25.0 mm, when the young are about 
40 days old. 
  Approximately 1 month elapses between the first 
appearance of white sucker spawners and the down- 
stream migration of the fry (Geen et al. 1966). The 
young remain in the gravel at the spawning grounds 
for 1-2 weeks after hatching, before they emerge to 
move downstream. These fry, 12-14 mm TL, move 
downstream almost entirely at night. According to 
Clifford (1972), as the fry become larger, many more 
move downstream near the surface of the water than 
near the stream's substrate. 
  In Erickson and John lakes (Vilas County) white 
sucker larvae were first collected in late May and in 
June (Faber 1967). Large numbers of larval white 
suckers were observed schooling in very shallow 
water (2-5 cm) near shore, and were regularly caught 
in the limnetic region after dark. 
  Larval white suckers (12-25 mm long) have oblique 
mouths and short intestines (Cross 1967). They feed 
near the surface on protozoans, diatoms, small crus- 
taceans, and bloodworms brought by currents into 
areas occupied by the schools of fry. As the young 
grow, the mouth becomes ventral, the intestine elon- 
gates, and the fish seek food mainly on the bottoms 
of streams or lakes. 
  Young white suckers are typically gregarious, and, 
during the first year of life, may form schools of a few 
fish to several hundred fish. They usually spread out 
side by side, facing the shore (Schneberger 1972c); 
when alarmed they hide in deep water, but usually 
return to shallow water in a few minutes. In lakes, 
white suckers under 51 mm (2 in) long usually feed 
in water 15-20 cm (6-8 in) deep along the shore. 
  The growth of young-of-year white suckers in 
northern Wisconsin reached 29 (24-33) mm on 4 July 
in the Wolf River (Forest County), and 44 mm by 20 
September in the Jump River (Price County). In cen- 
tral Wisconsin, they reached 33 (28-38) mm on 25 
June in the Little Eau Claire River (Portage County), 
and 66 (60-78) mm on 16 September in the Plover 
River (Portage County). In southern Wisconsin, young- 
of-year attained 30 (23-34) mm on 30 June in the 
Pecatonica River (Iowa County). 
  White suckers for age-groups I through VIII ap- 
pear in the table below. No 6- or 7-year-old males were 
taken from Lake Winnebago. Priegel determined that 
the average age at maturity was 2 for both males and 
females. All fish were mature at 3 years or older. 
  From sections of the pectoral fins, Vondracek back 
calculated total lengths (mm) at the annuli for white 
suckers from the Pensaukee River, a tributary to 
Green Bay: 1-males 175 (females 180); 2-292 (301); 
3-357 (374); 4-389 (415); 5-406 (438); 6-403 (445); 
7-414 (460); 8-421 (463); 9-429 (461); and 10-438 
(471). In white suckers from Green Bay and Lake 
Michigan, a small number of males mature at age II, 
and some females mature at age III. Most white suck- 
ers are mature at age IV. Data presented by Vondra- 
cek indicate that white suckers in Green Bay grow at 
a faster rate than they do in Lake Michigan. 
  In Spauldings Pond (Rock County), white suckers 
384-398 mm (15.1-15.7 in) TL were 3 years old 
(Threinen and Helm 1952). A 525-mm fish, collected 
from Roberts Lake (Forest County) on 8 July 1966, was 
estimated to be 11 years old; age was calculated by 
analysis of pectoral fin-ray sections (R. Puckett, pers. 
comm.). Beamish and Harvey (1969) found that, for 
some populations of white suckers, the scale method 
for calculating age is inaccurate after the fish have 
reached 5 years of age. 
  The largest known Wisconsin white sucker, which 
weighed 2.50 kg (5.5 lb), was taken from Lake Men- 
dota (Dane County) on 11 March 1976. 
  The condition (KTL) of white suckers, collected from 
the Biron Flowage of the Wisconsin River (Wood 
County) on 24 April, averaged 1.14 (0.85-1.36). All 
fish were in postspawning condition. 
  Both adult and juvenile white suckers feed 
throughout the day and night, but they feed more 
actively at night than in broad daylight. Observations 
at night have indicated that after dark adults move 
into shallower water to feed (Moyle 1969). This spe- 
cies has diversified feeding habits, taking any food 
                               Age and Growth (TL in mm) of the White Sucker
in Wisconsin 
Location                     I      II     III    IV      V      VI     VII
   VIII          Source 
Muskellunge L. (Vilas Co.)a 71     117    163     203    231    262     290
   310         Spoor (1938) 
L. Winnebago 
Males                       163    320    401     427    442            
                  Priegel (1976) 
Females                     163    330    411     452    448    498     523
L. Michigan, Green Bay 
Males                              324    355     388    410    417     427
   424         Vondracek (1977) 
Females                            311    369     414    439    442     466
aData converted by Vondracek (1977) from SL or FL, using conversion factors
presented in Carlander (1969). 

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