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.

Item Type:	Refereed Article
Keywords:	cod, haddock, seals, whiting, ecopath with ecosim, shelf ecosystem model
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Marine and Estuarine Ecology (incl. Marine Ichthyology)
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - Wild Caught
Objective Field:	Wild Caught Fin Fish (excl. Tuna)
UTAS Author:	Alexander, KA (Dr Karen Alexander)
ID Code:	107753
Year Published:	2015
Web of Science® Times Cited:	14
Deposited By:	IMAS Research and Education Centre
Deposited On:	2016-03-23
Last Modified:	2017-11-02
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