Distribution and relative abundance of fishes in Wisconsin

A statewide study of the inland waters of Wisconsin was initiated in 1974 by the Bureau of Research, Wisconsin Department of Natural Resources (DNR) to establish a comprehensive data base on the distribution and relative abundance of all fish species. Records composing this data base came mainly from a survey between 197 4 and 1986 of current statewide fish distribution. Numerous historical records (from 1900-72) were also included in the data base. Surveys to determine current distribution were primarily conducted in eastern, southern, west central, and northwestern Wisconsin. Sampling of basins in these areas during 197 4-86 was accomplished at 5,396 stations by Fish Distribution Study personnel, at 4,174 stations by other DNR personnel, and at 271 stations by non-DNR personnel. These stations covered approximately 50% of the state. During this period, 143 species were collected. Of these 143 species, 140 are believed to have reproducing populations in the inland waters ofWisconsin. According to the Department’s lists of endangered, threatened, and ”watch” species, the fishes collected during the fish distribution survey between 197 4 and 1986 included all 8 of the state’s endangered species, all6 of~ threatened species, and 16 ofthe 21 species on the Department’s watch list. These status designations were based on official listings of endangered and threatened species (per a 1982 Wisconsin Administrative Code) and an unofficial list (from 1985) of watch species for which a population problem was suspected but not known.
Data from the 197 4-86 period for Wisconsin were compared to those from the 1900-72 period. The early period records consisted of 2,179 non-DNR collections and 1,456 DNR collections. Two species that had not been previously reported from the state were collected in the later period. Three species have apparently been extirpated from the state. This report includes numerous tables, distribution maps of the species, and discussion on many aspects offish distribution in Wisconsin. It also sets out a sampling plan for completing the state survey. The data base generated to date has been shown to be of great value for the preparation of environmental impact assessments, development of master plans for the aquatic resource, and preparation of research proposals on nongame species, fish communities, and ecosystems. Use and value ofthis data base would undoubtedly increase ifthe sampling of the state were to be completed. It is, therefore, recommended that completion of this study be considered in the near future. Other recommendations are to update the data base with information from historical fish surveys, to continue the systematic recording of fish collected during routine DNR surveys, and to protect the habitat of endangered and threatened fish species.