Access Type

Open Access Thesis

Date of Award

1-1-2014

Degree Type

Thesis

Degree Name

M.S.

Department

Biological Sciences

First Advisor

Donna R. Kashian

Abstract

Efficient monitoring programs are essential for the early detection of invasive species. The Ohio Department of Natural Resources (ODNR) monitoring program encompassing 21 years of fish survey data from western Lake Erie was evaluated using Chao biodiversity analysis to determine the efficiency and precision of collection strategies of trawl and gillnet sampling, at detecting rare or non-native species. Overall, ODNR sampling annually accounted for ~80% of extant fish species, leaving gaps in coverage where rare and invasive species may be overlooked and proliferate.Obtaining 90% efficiency would require an estimated doubling of previous sampling effort. Computer simulations calculating different proportions of trawl and gillnet sampling effort indicate an advantage to mixing collection strategies by reducing effort, and reveals a range of effective proportions concerning the two collection techniques. In addition, population trends for several species were evaluated to better elucidate strengths and weakness of current monitoring programs. These results enable an analysis of maximized sampling efficiency to provide earlier detection of future introductions, reduce total costs, and facilitate an improved understanding of native community dynamics. Understanding variations in fish community structure across a lake system can improve efficiency of monitoring programs and better prepares responders to invasive species introductions. Analysis of historic fish data to help designate new areas of concern and sites of future sampling interest were developed by utilizing Chao biodiversity statistics to calculate the odds of sampling new species at these ODNR sampling locations across the western basin. Through comparison of offshore ODNR trawl and gillnet samples, and near shore electrofishing surveys conducted by the University of Toledo both in the 2011 season provide proof that differences in sampling equipment and habitat types lead to variations in sampling efficiency and fish community distribution. Through analysis of spatial trends in species incidence, monitoring programs can selectively target individual species and areas for further study to combat invasive species encroachment into native ecosystems.

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