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The effects of trawling and primary production on size-structured food webs in seabed ecosystems


Howarth, LM and Somerfield, PJ and Blanchard, JL and Waggitt, JJ and Allender, S and Hiddink, JG, The effects of trawling and primary production on size-structured food webs in seabed ecosystems, Canadian Journal of Fisheries and Aquatic Sciences, 77, (10) pp. 1659-1665. ISSN 0706-652X (2020) [Refereed Article]

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DOI: doi:10.1139/cjfas-2020-0025


Understanding how different drivers shape relationships between abundance and body mass (size spectra) is important for understanding trophic and competitive interactions in food webs and for predicting the effects of human pressures. Here, we sample seabed communities from small polychaetes (<0.001 g) to large fish (>1 kg) in the Celtic Sea and the western English Channel to examine how bottom trawling and primary production affect their size spectra and to compare these with predictions from a model that couples predator and detritivore communities. Size spectra were not well approximated by linear fits because of truncation of the size spectra of detritivores. Low primary production resulted in lower abundance of benthic fauna. Bottom trawling reduced the abundance of predators and large detritivores but allowed small detritivores to increase in abundance. These empirical size spectra were partly consistent with predictions from the size spectra model, showing that understanding the structuring of benthic communities requires a consideration of both size and functional group. The findings highlight the need for an ecosystem approach to understanding the effects of exploitation and climate change on marine ecosystems.

Item Details

Item Type:Refereed Article
Keywords:benthic size spectra, trawling, food-webs
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Assessment and management of benthic marine ecosystems
UTAS Author:Blanchard, JL (Professor Julia Blanchard)
ID Code:144018
Year Published:2020
Deposited By:Ecology and Biodiversity
Deposited On:2021-04-15
Last Modified:2021-05-19

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