{"pk":62835,"title":"Use of the SmeltCam as an Efficient Fish-Sampling Alternative Within the San Francisco Estuary","subtitle":null,"abstract":"Resource managers often rely on long-term monitoring surveys to detect trends in biological data. However, no survey gear is 100% efficient, and many sources of bias can be responsible for detecting or not detecting biological trends. The SmeltCam is an imaging apparatus developed as a potential sampling alternative to long-term trawling gear surveys within the San Francisco Estuary, California, to reduce handling stress on sensitive species like the Delta Smelt (\nHypomesus transpacificus\n). Although believed to be a reliable alternative to closed cod-end trawling surveys, no formal test of sampling efficiency has been implemented using the SmeltCam. We used a paired deployment of the SmeltCam and a conventional closed cod-end trawl within the Napa River and San Pablo Bay, a Bayesian binomial \nN\n-mixture model, and data simulations to determine the sampling efficiency of both deployed gear types to capture a Delta Smelt surrogate (Northern Anchovy, \nEngraulis mordax\n) and to test potential bias in our modeling framework. We found that retention efficiency—a component of detection efficiency that estimates the probability a fish is retained by the gear, conditional on gear contact—was slightly higher using the SmeltCam (mean = 0.58) than the conventional trawl (mean = 0.47, Probability SmeltCam retention efficiency > trawl retention efficiency = 94%). We also found turbidity did not affect the SmeltCam’s retention efficiency, although total fish density during an individual tow improved the trawl’s retention efficiency. Simulations also showed the binomial model was accurate when model assumptions were met. Collectively, our results suggest the SmeltCam to be a reliable alternative to sampling with conventional trawling gear, but future tests are needed to confirm whether the SmeltCam is as reliable when applied to taxa other than Northern Anchovy over a greater range of conditions.","language":"en","license":{"name":"Creative Commons Attribution 4.0","short_name":"CC BY 4.0","text":"Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.\n\nNo additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.","url":"https://creativecommons.org/licenses/by/4.0"},"keywords":[{"word":"Bayesian, gear retention efficiency, N-mixture model, Northern Anchovy, midwater trawl, Napa River, San Pablo Bay, Delta Smelt"}],"section":"Research Article","is_remote":true,"remote_url":"https://escholarship.org/uc/item/39k1772k","frozenauthors":[{"first_name":"Brock","middle_name":"M.","last_name":"Huntsman","name_suffix":"","institution":"US Geological Survey\nSacramento, CA 95819","department":""},{"first_name":"Fredrick","middle_name":"","last_name":"Feyrer","name_suffix":"","institution":"US Geological Survey\nSacramento, CA 95819","department":""},{"first_name":"Matthew","middle_name":"J.","last_name":"Young","name_suffix":"","institution":"US Geological Survey\nSacramento, CA 95819","department":""}],"date_submitted":"2021-06-02T05:49:39Z","date_accepted":"2021-06-02T05:49:39Z","date_published":"2021-06-10T07:00:00Z","render_galley":null,"galleys":[{"label":"","type":"pdf","path":"https://journalpub.escholarship.org/jmie_sfews/article/62835/galley/48516/download/"}]}