The Little Sioux River basin in northwest Iowa is the largest and most fish species-rich of Iowa’s river basins in western and southern Iowa that drain to the Missouri River. Since the time of the earliest fish surveys in the 1890s, 64 species of fish from 19 families have been recorded for the lakes, rivers, and streams of the Little Sioux River basin. Fifty-four of these 64 fish species are known to occur, or may yet occur, in the Little Sioux River and its tributary streams. The basin's more diverse fish fauna is attributable to both geology and hydrology; the well-intentioned efforts of man also likely play a role. As is typical for all of Iowa’s river basins, the minnow family contributes the most fish species (20), although the sucker and catfish families each contribute six species, and the sunfish family, which includes Largemouth Bass and Smallmouth Bass as well as White and Black crappies, contributes eight species. Due to their declining populations or limited occurrence in the state, six fish species in the Little Sioux River and its tributaries have been identified by Iowa DNR as "species of greatest conservation need." Two of these six species are believed to be gone from the basin.
Speaker: John Olson is a native of Red Oak in southwest Iowa; he has lived in Ankeny since 1994. John retired in 2017 after a 30-year career with the Iowa DNR Water Quality Bureau in Des Moines. He has been involved with stream fish survey work in Iowa since attending Iowa State University, where he participated in a statewide survey of Iowa fishes from 1981-1984. He has a degree in Animal Ecology from Iowa State with an emphasis in fisheries biology. John assisted with stream fish surveys while at Iowa DNR, and he continues to pursue his interest in Iowa fishes, especially their distributions, in retirement. Over the last 45 years, he has conducted or participated in over 1,200 fish surveys on Iowa streams and rivers and has published several articles and reports on Iowa fishes.
John Olson
Source: Ben Fowler/PARKS360 | 2023