Biennial Report - January 1995 - December 1996 | Reports | Minnesota Cooperative Fish and Wildlife Research Unit

Minnesota Cooperative Fish and Wildlife Research Unit University of Minnesota Department of Fisheries, Wildlife, and Conservation Biology 1980 Folwell Avenue, 138 Hodson Hall St. Paul, MN 55108 phone: 612-624-3421 fax: 612-625-5299 [email protected] Activities 1995-1996 | Reports | Minnesota Cooperative Fish and Wildlif... http://fwcb.cfans.umn.edu/coop/reports/9695pubs.html 2 of 11 11/15/2012 11:55 AM Availability of spawning habitat and summer microhabitat for adult smallmouth bass Micropterus dolomieu appears to be limited in a 1.5 km section of the Cloquet River, a controlled river located in northern Minnesota, near the northern edge of the smallmouth bass range. This study included four objectives: (1) Identify sites used for spawning and determine availability of suitable spawning habitat, (2) Estimate the number of males capable of spawning, (3) Determine the availability and use of suitable summer microhabitat, and (4) Establish a relation between adult smallmouth bass and crayfish habitat use. Habitat availability was quantified by 20 transects (1021 point measurements) distributed throughout the study reach during low flow and high flow conditions. A total of nine nests were located and monitored during the 1993 and 1994 spawning seasons. All nests failed, presumably due to flooding. Physical characteristics at the nests included low mean water column velocity (<0.06m/s), intermediate depth (>0.4m), and close proximity to cover. The study reach contained <10% suitable spawning habitat at low flow and 3% at high flow. Ninety-one occupied microhabitat sites were surveyed during 1993 and 1994. At each microhabitat site, a total of eight variables were recorded. A combination of depth and mean water column velocity appeared to be important in the selection of summer microhabitat by adult smallmouth bass. Less than 7% of the study reach at low flow and 10% at high flow had suitable summer microhabitat. Crayfish were determined to be an important part of the adult smallmouth bass diet, 92% of the smallmouth bass that contained food, ingested at least one crayfish. Smallmouth bass used similar mean water column velocities and substrates as crayfish. McCarthy, William F. 1995. Direct and indirect effects of esfenvalerate on wetland biota. M.S. Thesis, University of Minnesota, St. Paul. 81pp.