Estimation of time-varying selectivity in stock assessments using state-space models
Time-varying selectivity is one of the main challenges in single species age-based
assessment models. In classical deterministic VPA-type models the fishing mortality rates …
assessment models. In classical deterministic VPA-type models the fishing mortality rates …
Accounting for variable recruitment and fishing mortality in length-based stock assessments for data-limited fisheries
In fisheries with limited capacity for monitoring, it is often easier to collect length
measurements from fishery catch than quantify total catch. Conventional stock assessment …
measurements from fishery catch than quantify total catch. Conventional stock assessment …
Develo** spatio-temporal models using multiple data types for evaluating population trends and habitat usage
Spatio-temporal models have become key tools for evaluating population trends and habitat
usage. We developed a spatio-temporal modelling framework employing a combination of …
usage. We developed a spatio-temporal modelling framework employing a combination of …
Three problems with the conventional delta-model for biomass sampling data, and a computationally efficient alternative
JT Thorson - Canadian Journal of Fisheries and Aquatic …, 2018 - cdnsciencepub.com
Ecologists often analyse biomass sampling data that result in many zeros, where remaining
samples can take any positive real number. Samples are often analysed using a “delta …
samples can take any positive real number. Samples are often analysed using a “delta …
Evaluation of the impacts of different treatments of spatio-temporal variation in catch-per-unit-effort standardization models
Many stock assessments heavily rely on indices of relative abundance derived from fisheries-
dependent catch-per-unit-effort (CPUE) data. Therefore, it is critical to evaluate different …
dependent catch-per-unit-effort (CPUE) data. Therefore, it is critical to evaluate different …
Accounting for correlated observations in an age-based state-space stock assessment model
Fish stock assessment models often rely on size-or age-specific observations that are
assumed to be statistically independent of each other. In reality, these observations are not …
assumed to be statistically independent of each other. In reality, these observations are not …
The surprising sensitivity of index scale to delta-model assumptions: recommendations for model-based index standardization
Delta-models (aka hurdle models) are widely used to fit biomass samples that include zeros
and a skewed response for positive catches, and spatio-temporal extensions of these …
and a skewed response for positive catches, and spatio-temporal extensions of these …
Predicting abundance indices in areas without coverage with a latent spatio-temporal Gaussian model
ON Breivik, F Aanes, G Søvik, A Aglen… - ICES Journal of …, 2021 - academic.oup.com
A general spatio-temporal abundance index model is introduced and applied on a case
study for North East Arctic cod in the Barents Sea. We demonstrate that the model can …
study for North East Arctic cod in the Barents Sea. We demonstrate that the model can …
Spatiotemporal analysis of compositional data: increased precision and improved workflow using model-based inputs to stock assessment
Stock assessment models are fitted to abundance-index, fishery catch, and age–length–sex
composition data that are estimated from survey and fishery records. Research has …
composition data that are estimated from survey and fishery records. Research has …
Exploring the limits of spatiotemporal and design-based index standardization under reduced survey coverage
Indices of abundance derived from fisheries-independent surveys play a crucial role in
sustainable fisheries management. While design-based methods provide unbiased indices …
sustainable fisheries management. While design-based methods provide unbiased indices …