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Tuesday, January 30 • 11:00am - 11:20am
SYMPOSIA-07: Validating the Use of Baited, Tandem Hoop Nets to Index Ohio Reservoir Channel Catfish Density

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AUTHORS. Stephen M. Tyszko, Jeremy J. Pritt, Joseph D. Conroy, Kevin S. Page, Richard R. Budnik - Ohio Department of Natural Resources, Division of Wildlife

ABSTRACT. The Ohio Department of Natural Resources, Division of Wildlife seeks to develop a standard method to index Channel Catfish Ictalurus punctatus density and size structure in reservoirs, and tandem hoop net sets most effectively catch Channel Catfish.  We estimated the catchability of Channel Catfish with tandem hoop net sets in Ohio reservoirs and compared statistical power to detect differences in density as well as false positive rate.  We estimated catchability and density during mark-recapture experiments that included two recapture events per week during May–July in Dillon Lake (2016) and Burr Oak Lake (2017).  Catchability (q) was greatest in June and July and was similar for our two study reservoir populations (Burr Oak Lake q, 95 % confidence limits [CL]: 0.041, 0.031–0.050; Dillon Lake: 0.035, 0.032–0.037).  Channel Catfish density estimates differed, however (Burr Oak Lake: 21 catfish/ha, 95% CL 20–22; Dillon Lake: 49 catfish/ha, 47–51).  When including data from the entire sampling period (May–July), the probability of detecting a difference in Channel Catfish density increased from 39% to 94% as sample size increased from 5 net sets to 20 net sets.  The probability of detecting differences in density increased, however, when including data only from a restricted June–July period.  At the reservoir with low Channel Catfish density, false positive rate (detecting a difference in density when one did not exist) was similar for data collected during the entire sampling period and during the restricted period.  At the reservoir with the high density population, false positive rate was greater when sampling during the entire period but decreased when sampling during a restricted period.  Results will be used to design a standard sampling program for Ohio reservoir Channel Catfish populations, sampling during a period that maximizes catchability and minimizes its variability.  

Tuesday January 30, 2018 11:00am - 11:20am CST