Silver carp (Hypophthalmichthys molitrix) have invaded most of the Mississippi River and its tributaries. Although fish age is routinely used to inform management decisions, aging structures for bighead and silver carp have not been validated against known-age fish to ensure accuracy and utility. We used known-age fish reared in Chinese aquaculture and collected from the LaGrange Reach of the Illinois River (tracked annually from a strong 2014-year class) to validate aging structures from silver carp. We removed vertebrae, lapillus otoliths, pectoral spines, and postcleithra from each individual. Each structure was sectioned and prepared accordingly. Annuli were counted and each annulus measured from the focus using Leica Chronic Wasting Disease was discovered in one county in northern Illinois in 2002 and is now in 17 counties in the state with 685 known cases. A mail survey was sent to 3,000 Illinois deer hunters in CWD counties (response rate = 58%) and 8,000 hunters outside of the CWD zone (response rate = 56%). The questionnaire examined trust in the Illinois Department of Natural Resources (IDNR) CWD management and information, and perceived risk to both humans and the deer herd. Four hypotheses were advanced. Hunters in CWD counties will differ from hunters in non-CWD counties in terms of their trust in IDNR CWD information (H1), trust in IDNR CWD management (H2), perceived risk to human health (H3), and perceived risk to deer herd health (H4). Trust in information was measured using five variables (Cronbach’s a = .94) and trust in management with three variables (a = .93); both sets of variables coded on 7-point bipolar scales. Perceived risk to human health was measured using one 4-point unipolar variable and three 7-point bipolar variables (a = .83). Perceived risk to deer herd health was measured using one 4-point unipolar variable and four 7-point bipolar variables (a = .92). Based on independent samples t-tests, all four hypotheses were supported. Trust in INDR management and information was greater among non-CWD county hunters than CWD county hunters. Perceived risks to both humans and the deer herd were greater among CWD county hunters than non-CWD county hunters. In all cases, however, effect sizes were minimal. Discussion highlights the influence of proximity of CWD on perceptions of the disease and management.
|Published - 2018
|2018 Midwest Fish and Wildlife Conference - Milwaukee, United States
Duration: Jan 28 2018 → Jan 31 2018
Conference number: 78
|2018 Midwest Fish and Wildlife Conference
|1/28/18 → 1/31/18