Becker, George C. / Fishes of Wisconsin
Sucker family - catostomidae, pp. 607-691 ff. PDF (39.5 MB)
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 311 369 414 439 442 466 472 aData converted by Vondracek (1977) from SL or FL, using conversion factors presented in Carlander (1969).
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