An interim harvest strategy for Taiga Bean geese

Fred A. Johnson; Mikko Alhainen; Anthony D. Fox; Jesper Madsen

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USGS · 70198133

An interim harvest strategy for Taiga Bean geese

Fred A. Johnson·Mikko Alhainen·Anthony D. Fox·Jesper Madsen

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Abstract

In 2016 the AEWA European Goose Management International Working Group (EGM IWG) adopted document AEWA/EGM IWG 1.8 (Johnson et al. 2016), which contained initial elements of an Adaptive Harvest Management programme for Taiga Bean Geese. This report addresses a number of limitations with the population model presented in that document, and provides up-to-date population projections for the Central Management Unit under a range of constant harvest rates. Based on simulations for the 2017-2025 timeframe, median population size was near the median goal of 70,000 in 2019, 2020, and 2021 for harvest rates of birds aged one year or more of 0.00, 0.02, and 0.04, respectively. Simulated population sizes generally increased over the timeframe, albeit with a lot of variation and with the degree of uncertainty increasing over time. With a harvest rate of 0.02, harvests averaged 1,848 (95% CI: 1,403 – 2,492) over the timeframe; a harvest rate of 0.04 produced an average harvest of 3,484 (95% CI: 2,617 – 4,884). Future work for the Central Management Unit will involve development of a dynamic harvest strategy by employing a Markov decision process, in which multiple, possibly competing, management objectives can be addressed.

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Fred A. Johnson, Mikko Alhainen, Anthony D. Fox, Jesper Madsen. 2018. An interim harvest strategy for Taiga Bean geese. https://pubs.usgs.gov/publication/70198133

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