University of Tasmania

File(s) under permanent embargo

Investigating the recent decline in gadoid stocks in the west of Scotland shelf ecosystem using a foodweb model

journal contribution
posted on 2023-05-18, 18:14 authored by Karen AlexanderKaren Alexander, Heymans, JJ, Magill, S, Tomczak, MT, Holmes, SJ, Wilding, TA
Abundance and biomass of cod, haddock, and whiting in the waters off of the west coast of Scotland (wcoS) have undergone large changes in recent years, most notably a recent decline. These three species contribute a considerable part of Scottish demersal landings from this area and as such it is important to understand why these stocks are behaving the way they are. A number of explanations for the decline have been proposed, including: seal predation, pressure from Nephrops trawls, and fishing pressure more generally. We used an ecosystem model of the wcoS continental shelf (,200 m depth) to investigate whether these proposed explanations for declining gadoid stocks are feasible. Results suggest that the rise in the grey seal population over recent years has not led to the decline in gadoid stocks; there is insufficient bycatch by the Nephrops fleet to have a large impact on gadoid stocks; however, fishing, as a key driver of the west of Scotland shelf ecosystem, has impacted stocks and by decreasing fishing levels to maximum sustainable yield cod biomass may increase slightly though not returning to previous levels. Although this means we are little further forward in understanding the cause of recent gadoid declines in the area, the development of this model has enabled us to further our knowledge and understanding of aspects of trophic structure and the impacts of fishing on the wcoS.


Publication title

ICES Journal of Marine Science








Institute for Marine and Antarctic Studies


Academic Press Ltd Elsevier Science Ltd

Place of publication

24-28 Oval Rd, London, England, Nw1 7Dx

Rights statement

Copyright 2014 International Council for the Exploration of the Sea

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught fin fish (excl. tuna)

Usage metrics

    University Of Tasmania


    Ref. manager