Becker, George C. / Fishes of Wisconsin
Minnow and carp family - cyprinidae, pp. 415-605 ff. PDF (93.4 MB)
416 Minnow and Carp Family-Cyprinidae In most insectivorous minnows, the digestive tract is a simple S- shaped structure which, when extended, is generally less than the min- now's total length. The lining of the body cavity is silvery, and it may be lightly speckled with dark pigments. Vegetable-feeders, however, have elongated digestive tracts in which additional loops develop from the original S-shaped structure. As the intestine lengthens, the lining of the body cavity darkens to dusky or black. During the breeding season, the males of many minnow species sport bright, attractive colors and breeding tubercles in various shapes and numbers. These features have made our North American minnows at- tractive to European fish fanciers. Breeding tubercles have three func- tions: they aid in the construction of the nest, they are weapons of com- bat between fighting males, and they enable males to hold females during spawning (Reighard 1903). Between the swim bladder and the inner ear is the Weberian ossicle device, a chain of three bones derived from the anteriormost vertebrae. These increase the minnow's hearing sensitivity, and Winn and Stout (1960) suggested that perhaps this has been a reason for its success in the fresh waters of the world. Another successful feature in many minnow species is continuous spawning over a long season, commonly called fractional spawning. Ni- kolsky (1963) noted that fractional spawning decreases the chance that one or more entire generations will be lost to unfavorable environmental conditions, such as high water or flood stages. Many intra- and occasionally inter-generic hybrids occur. Minnow hy- bridization may result from drought conditions on small, spring-fed streams that support large populations of fishes (Cross and Minckley 1960). Unusual crowding of spawning fishes would increase the oppor- tunity for fertilization of the eggs of one species by sperm from another species, and, as noted by Hubbs (1955), hybridization of fishes seems most common in areas that have been subject to radical climatic change within the past 20,000 years, and in streams that have been altered re- cently by the activities of man. The use of and demand for bait minnows has led to the development of an important business in and around resort or fishing areas. In 1957, the Wisconsin Department of Natural Resources issued 853 bait dealer licenses. The dealers sold almost 23.5 million minnows with an estimated value of $783,000. The total volume of all minnows used was estimated at 36 million, with a market value of about $1.2 million (Niemuth 1959). Great demand and uncertain supply have caused many minnow deal- ers and people who handle live bait to propagate and rear minnows in natural or artificial ponds. Today some people supplement their incomes by raising minnows, while others live entirely off the profits derived from raising and selling minnows. Procedures and methods for raising minnows are discussed by Hasler et al. (1946), Dobie et al. (1956), and Hubbs and Cooper (1936). In recent years tank trucks have transported thousands of golden shiners from Arkansas to Wisconsin to help meet the demand. The minnow is one of the most important commercial food fishes in the state. In 1976 over 1.25 million kg (2.75 million lb) of carp worth
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