Quantifying status and trends from monitoring surveys: application to Pygmy Whitefish (Prosopium coulterii) in Lake Superior

• Main Authors: van der Lee, Adam S., Vinson, Mark R., Koops, Marten A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: University of Toronto 2021
• Subjects: Canada; Laplace; Pygmy whitefish
• Online Access: http://hdl.handle.net/1807/110260; http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2021-0155

Population assessments of fish species often rely on data from surveys with different objectives such as measuring biodiversity or community dynamics. These surveys often contain spatial-temporal dependencies that can greatly influence conclusions drawn from analyses. Pygmy whitefish (PWF, Prosopium coulterii) populations in Lake Superior were recently assessed as Threatened by the Committee on the Status of Endangered Species in Canada which motivated a thorough analysis of available data to improve our understanding of its population status. The U.S. Geological Survey conducts annual bottom trawl surveys in Lake Superior that commonly captures PWF. We used these data (1989-2018) to model temporal trends in PWF biomass-density and make lake-wide population projections. We used a Bayesian approach, Integrated Nested Laplace Approximation (INLA), and compared the impact of including different random structures on model fit. Inclusion of spatial structure improved model fit and conclusions differed from models omitting random effects. PWF populations have experienced periodic fluctuations in biomass-density since 1989, though 2018 may represent the lowest density in the 30-year time series. Lake-wide biomass was estimated to be 71.5t. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.