doi abstract bibtex

Using an exploitation rate (not fishing mortality) based virtual population analysis (VPA) algorithm, which is itself a generalization of the Pope approximation to the original VPA equations, I show how to derive variance estimates for the key VPA outputs (recruitment, SSB, exploitation rates) given variance information on the key inputs (catch-at-age/terminal exploitation rates). Given the alternative VPA algorithm permits closed-form solutions for the outputs in terms of the inputs, the delta method is employed to obtain the variance estimates, removing the need for complex simulation techniques. Using North Sea herring data as an example, the methods utility is demonstrated by exploring the impact of aging error in the catch data and tuning error on the precision of estimates of SSB, recruitment and exploitation rates, and the parameters of the stock-recruit relationship.

@article{ ISI:000310599000002, Author = {Hillary, R. M.}, Title = {{ASSESSING COMPONENTS OF UNCERTAINTY IN VPA ABUNDANCE AND MORTALITY ESTIMATES USING AN ALTERNATIVE EXPLOITATION RATE-BASED ALGORITHM}}, Journal = {{NATURAL RESOURCE MODELING}}, Year = {{2012}}, Volume = {{25}}, Number = {{4}}, Pages = {{574-598}}, Month = {{NOV}}, Abstract = {{Using an exploitation rate (not fishing mortality) based virtual population analysis (VPA) algorithm, which is itself a generalization of the Pope approximation to the original VPA equations, I show how to derive variance estimates for the key VPA outputs (recruitment, SSB, exploitation rates) given variance information on the key inputs (catch-at-age/terminal exploitation rates). Given the alternative VPA algorithm permits closed-form solutions for the outputs in terms of the inputs, the delta method is employed to obtain the variance estimates, removing the need for complex simulation techniques. Using North Sea herring data as an example, the methods utility is demonstrated by exploring the impact of aging error in the catch data and tuning error on the precision of estimates of SSB, recruitment and exploitation rates, and the parameters of the stock-recruit relationship.}}, Publisher = {{WILEY-BLACKWELL}}, Address = {{111 RIVER ST, HOBOKEN 07030-5774, NJ USA}}, Type = {{Article}}, Language = {{English}}, Affiliation = {{Hillary, RM (Reprint Author), CSIRO Marine \& Atmospher Res, Wealth Oceans Natl Res Flagship, Castray Esplanade, Hobart, Tas 7001, Australia. CSIRO Marine \& Atmospher Res, Wealth Oceans Natl Res Flagship, Castray Esplanade, Hobart, Tas 7001, Australia.}}, DOI = {{10.1111/j.1939-7445.2011.00113.x}}, ISSN = {{0890-8575}}, EISSN = {{1939-7445}}, Keywords = {{Virtual population analysis; exploitation rate; catch-at-age; uncertainty}}, Keywords-Plus = {{VIRTUAL POPULATION ANALYSIS; FISHERIES STOCK ASSESSMENT; COHORT ANALYSIS; CATCH EQUATION; AGE DATA; ERRORS; RECRUITMENT; VARIANCE; MODELS; TIME}}, Research-Areas = {{Environmental Sciences \& Ecology; Mathematics}}, Web-of-Science-Categories = {{Environmental Sciences; Mathematics, Interdisciplinary Applications}}, Author-Email = {{rich.hillary@csiro.au}}, ResearcherID-Numbers = {{Hillary, Richard/L-3300-2013}}, Number-of-Cited-References = {{31}}, Times-Cited = {{0}}, Usage-Count-Last-180-days = {{0}}, Usage-Count-Since-2013 = {{4}}, Journal-ISO = {{Nat. Resour. Model.}}, Doc-Delivery-Number = {{030VU}}, Unique-ID = {{ISI:000310599000002}}, OA = {{No}}, DA = {{2017-08-17}}, }

Downloads: 0