dc.contributor.advisor | Shoup, Daniel E. | |
dc.contributor.author | Johnson, Garrett | |
dc.date.accessioned | 2018-06-25T16:31:20Z | |
dc.date.available | 2018-06-25T16:31:20Z | |
dc.date.issued | 2017-12-01 | |
dc.identifier.uri | https://hdl.handle.net/11244/300300 | |
dc.description.abstract | Gizzard Shad (Dorosoma cepedianum) are an important prey species that are commonly sampled with gill nets. However, horizontally-oriented methodologies have the potential to produce better Gizzard Shad data with less effort. Before horizontal beaming can be used as a sampling gear for Gizzard Shad, accuracy and precision need to be examined to determine if this approach provides reliable and consistent data. Further, Gizzard Shad-specific relationships between acoustic target strength (TS) and total length (TL) should be derived to ensure density estimates are accurate. I tested the accuracy and precision of horizontal beaming by sampling known populations of Gizzard Shad in a net pen (15-m long x 15-m wide x 4.5-m deep with 6.35-mm square mesh). I found horizontal beaming accurately detected changes in density (R2=0.63) with increased precision (mean CV of 6% among all trials) than other gears used to sample Gizzard Shad. Given that TS changes with fish orientation, I developed an orientation-based TS-TL equation to increase accuracy of hydroacoustic estimates. A catenary (U-Shape) function was best at representing the change in TS at different fish orientations (conditional R2 = 0.71 and marginal R2 = 0.67). I also compared echo integration results using six different TS-TL equations (2 from this paper and 4 from previous literature) using 23 fish aggregations imaged in the field. Equation choice had a significant effect on density estimates (P<0.01) indicating care should be taken when selecting TS-TL equations for use in hydroacoustic surveys. | |
dc.format | application/pdf | |
dc.language | en_US | |
dc.rights | Copyright is held by the author who has granted the Oklahoma State University Library the non-exclusive right to share this material in its institutional repository. Contact Digital Library Services at lib-dls@okstate.edu or 405-744-9161 for the permission policy on the use, reproduction or distribution of this material. | |
dc.title | Assessing Horizontally-oriented Acoustic Methods for Gizzard Shad Abundance Assessments: Accuracy, Precision and Target Orientation | |
dc.contributor.committeeMember | Shoup, Daniel E. | |
dc.contributor.committeeMember | Long, James M. | |
dc.contributor.committeeMember | Boswell, Kevin M. | |
osu.filename | Johnson_okstate_0664M_15543.pdf | |
osu.accesstype | Open Access | |
dc.description.department | Natural Resources and Ecology Management | |
dc.type.genre | Thesis | |
dc.type.material | text | |