title: Structured additive distributional regression for analysing landings per unit effort in fisheries research.
abstract: We analysed the landings per unit effort (LPUE) from the Barcelona trawl fleet targeting the red shrimp (Aristeus antennatus) using novel Bayesian structured additive distributional regression to gain a better understanding of the dynamics and determinants of variation in LPUE. The data set, covering a time span of 17 years, includes fleet-dependent variables (e.g. the number of trips performed by vessels), temporal variables (inter- and intra-annual variability) and environmental variables (the North Atlantic Oscillation index). Based on structured additive distributional regression, we evaluate (i) the gain in replacing purely linear predictors by additive predictors including nonlinear effects of continuous covariates, (ii) the inclusion of vessel-specific effects based on either fixed or random effects, (iii) different types of distributions for the response, and (iv) the potential gain in not only modelling the location but also the scale/shape parameter of these distributions. Our findings support that flexible model variants are indeed able to improve the fit considerably and that additional insights can be gained. Tools to select within several model specifications and assumptions are discussed in detail as well.
authors.affiliation: Institut de Ciències del Mar (ICM-CSIC), Psg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain. Electronic address: mamouridis@icm.csic.es.
authors.forename: Valeria
authors.initials: V
authors.lastname: Mamouridis
authors.affiliation: Georg-August-Universität Gättingen, 37073 Gättingen, Germany.
authors.forename: Nadja
authors.initials: N
authors.lastname: Klein
authors.affiliation: Georg-August-Universität Gättingen, 37073 Gättingen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kneib
authors.affiliation: Department of Biostatistics, School of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Cadarso Suarez
authors.affiliation: Institut de Ciències del Mar (ICM-CSIC), Psg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Maynou
mesh_terms: D000818:Animals; D033364:Decapoda; D005398:Fisheries; D008962:Models, Theoretical
keywords: Generalised additive models for location; Landings per unit effort; Markov chain Monte Carlo simulation; Mixed models; North Atlantic Oscillation; North-Western Mediterranean; Red shrimp fishery; Scale and shape