Browsing Brage IMR by Author "Aldrin, Magne Tommy"
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Caveats with estimating natural mortality rates in stock assessment models using age aggregated catch data and abundance indices
Aldrin, Magne Tommy; Aanes, Fredrik L; Tvete, Ingunn Fride; Aanes, Sondre; Subbey, Samuel (Peer reviewed; Journal article, 2021)We consider the challenge in estimating the natural mortality, M, in a standard statistical fish stock assessment model based on time series of catch- and abundance-at-age data. Though anecdotal evidence and empirical ... -
Detecting significant retrospective patterns in state space fish stock assessment
Breivik, Olav Nikolai; Aldrin, Magne Tommy; Fuglebakk, Edvin; Nielsen, Anders (Peer reviewed; Journal article, 2023)Retrospective patterns are commonly investigated to validate fish stock assessment models. A widely applied measure for retrospective bias is Mohn’s ρ and corresponding retrospective plots. However, retrospective patterns ... -
Final report for the REDUS project - Reduced Uncertainty in Stock Assessment
Olsen, Erik Joel Steinar; Aanes, Sondre; Aldrin, Magne Tommy; Breivik, Olav Nikolai; Fuglebakk, Edvin; Goto, Daisuke; Handegard, Nils Olav; Hansen, Cecilie; Holmin, Arne Johannes; Howell, Daniel; Johnsen, Espen; Jourdain, Natoya; Korsbrekke, Knut; Ono, Kotaro; Otterå, Håkon Magne; Perryman, Holly Ann; Subbey, Samuel; Søvik, Guldborg; Umar, Ibrahim; Vatnehol, Sindre; Vølstad, Jon Helge (Rapport fra havforskningen;2021 - 16, Research report, 2021)The REDUS project (2016-2020) has been a strategic project at the Institute of Marine Research (IMR) aimed at quantifying and reducing the uncertainty in data-rich and age-structured stock assessments (e.g., cod, herring, ... -
The specification of the data model part in the SAM model matters
Aldrin, Magne Tommy; Tvete, Ingunn Fride; Aanes, Sondre; Subbey, Samuel (Peer reviewed; Journal article, 2020)This paper considers a general state-space stock assessment modeling framework that integrates a population model for a fish stock and a data model. This way observed data are linked to unobserved quantities in the population ...