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Estimating the Annual Spawning Run Size and Population Size of the Southern Distinct Population Segment of Green Sturgeon
Author(s) -
Mora Ethan A.,
Battleson Ryan D.,
Lindley Steven T.,
Thomas Michael J.,
Bellmer Russ,
Zarri Liam J.,
Klimley A. Peter
Publication year - 2018
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1002/tafs.10009
Subject(s) - fishery , population size , endangered species , threatened species , acipenser , population , abundance (ecology) , bycatch , geography , biology , sturgeon , ecology , environmental science , habitat , fish <actinopterygii> , demography , sociology
The Southern Distinct Population Segment of Green Sturgeon Acipenser medirostris spawns in the Sacramento River, California, and is listed as a threatened species under the U.S. Endangered Species Act. We estimated the spawning run size and population size in 2010–2015 by using dual‐frequency identification sonar ( DIDSON ) sampling, underwater video camera species identification, and acoustic tag detections. Spawning run size varied from 336 to 1,236 individuals. We estimated the total population size to be 17,548 individuals (95% confidence interval [ CI ] = 12,614–22,482). The estimated number of adults was 2,106 (95% CI = 1,246–2,966), the estimated number of juveniles was 4,387 (95% CI = 2,595–6,179), and the estimated number of subadults was 11,055 (95% CI = 6,540–15,571). This study provides the first estimate of Sacramento River Green Sturgeon run size and initiates a time series of abundance that can inform Endangered Species Act recovery processes. Furthermore, these absolute abundance estimates provide a context for evaluating the significance of impacts, such as bycatch in coastal fisheries or entrainment in water diversions, where the number of impacted individuals is known.