TY - JOUR
T1 - Looking in the rear-view mirror
T2 - Bias and retrospective patterns in integrated, age-structured stock assessment models
AU - Hurtado-Ferro, Felipe
AU - Szuwalski, Cody S.
AU - Valero, Juan L.
AU - Anderson, Sean C.
AU - Cunningham, Curry J.
AU - Johnson, Kelli F.
AU - Licandeo, Roberto
AU - McGilliard, Carey R.
AU - Monnahan, Cole C.
AU - Muradian, Melissa L.
AU - Ono, Kotaro
AU - Vert-Pre, Katyana A.
AU - Whitten, Athol R.
AU - Punt, André E.
N1 - Publisher Copyright:
© 2014 © International Council for the Exploration of the Sea 2014. All rights reserved.
PY - 2014/11/4
Y1 - 2014/11/4
N2 - Retrospective patterns are systematic changes in estimates of population size, or other assessment model-derived quantities, that occur as additional years of data are added to, or removed from, a stock assessment. These patterns are an insidious problem, and can lead to severe errors when providing management advice. Here, we use a simulation framework to show that temporal changes in selectivity, natural mortality, and growth can induce retrospective patterns in integrated, age-structured models. We explore the potential effects on retrospective patterns of catch history patterns, as well as model misspecification due to not accounting for time-varying biological parameters and selectivity. We show that non-zero values for Mohn's ρ (a common measure for retrospective patterns) can be generated even where there is no model misspecification, but the magnitude of Mohn's ρ tends to be lower when the model is not misspecified. The magnitude and sign of Mohn's ρ differed among life histories, with different life histories reacting differently from each type of temporal change. The value of Mohn's ρ is not related to either the sign or magnitude of bias in the estimate of terminal year biomass. We propose a rule of thumb for values of Mohn's ρ which can be used to determine whether a stock assessment shows a retrospective pattern.
AB - Retrospective patterns are systematic changes in estimates of population size, or other assessment model-derived quantities, that occur as additional years of data are added to, or removed from, a stock assessment. These patterns are an insidious problem, and can lead to severe errors when providing management advice. Here, we use a simulation framework to show that temporal changes in selectivity, natural mortality, and growth can induce retrospective patterns in integrated, age-structured models. We explore the potential effects on retrospective patterns of catch history patterns, as well as model misspecification due to not accounting for time-varying biological parameters and selectivity. We show that non-zero values for Mohn's ρ (a common measure for retrospective patterns) can be generated even where there is no model misspecification, but the magnitude of Mohn's ρ tends to be lower when the model is not misspecified. The magnitude and sign of Mohn's ρ differed among life histories, with different life histories reacting differently from each type of temporal change. The value of Mohn's ρ is not related to either the sign or magnitude of bias in the estimate of terminal year biomass. We propose a rule of thumb for values of Mohn's ρ which can be used to determine whether a stock assessment shows a retrospective pattern.
KW - bias
KW - fisheries stock assessment
KW - integrated analysis
KW - retrospective patterns
KW - simulation
KW - statistical age-structured models
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U2 - 10.1093/icesjms/fsu198
DO - 10.1093/icesjms/fsu198
M3 - Article
AN - SCOPUS:84922466792
SN - 1054-3139
VL - 72
SP - 99
EP - 110
JO - ICES Journal of Marine Science
JF - ICES Journal of Marine Science
IS - 1
ER -