Development of a Model for Predicting Large Scale Spatio-Temporal Variability in Juvenile Fish Abundance from Electrofishing Data : Scottish Marine and Freshwater Science Vol 6 No 6

• Main Author: Millar C P
• Format: Article in Journal/Newspaper
• Language: English
• Published: Marine Scotland Science 2015
• Subjects: Fish abundance in water bodies; Atlantic salmon
• Online Access: https://dx.doi.org/10.7489/1616-1; https://data.marine.gov.scot/dataset/development-model-predicting-large-scale-spatio-temporal-variability-juvenile-fish-abundance

Models of juvenile salmonid abundance are required to inform electrofishing based assessment approaches and potentially as an intermediate step in scaling conservation limits from data rich to data poor catchments. This report describes an approach for modelling large-scale spatio-temporal variability in fish densities using GIS derived covariates. The technical challenges, modelling approaches and software developed during the project are described. The utility of the approach was illustrated by fitting models to data on Atlantic salmon fry. : Multi-pass electrofishing data was collated from fisheries trusts, fisheries boards, SEPA and Marine Scotland. Covariates describing spatial, temporal and habitat variability were obtained for each sampling event. A two stage likelihood based modelling approach was developed. Firstly, capture probability was modelled in relation to covariates. Secondly, densities were modelled in relation to covariates, conditional on estimated capture probabilities. A software package was developed for the R statistical programming environment to perform the analysis.