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A trait-based metric sheds new light on the nature of the body size-depth relationship in the deep sea


Mindel, BL and Webb, TJ and Neat, FC and Blanchard, JL, A trait-based metric sheds new light on the nature of the body size-depth relationship in the deep sea, Journal of Animal Ecology, 85, (2) pp. 427-436. ISSN 0021-8790 (2016) [Refereed Article]

Copyright Statement

Copyright 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society

DOI: doi:10.1111/1365-2656.12471


1.  Variation within species is an often-overlooked aspect of community ecology, despite the fact that the ontogenetic structure of populations influences processes right up to the ecosystem level. Accounting for traits at the individual level is an important advance in the implementation of trait-based approaches in understanding community structure and function.

2.  We incorporate individual- and species-level traits into one succinct assemblage structure metric, fractional size, which is calculated as the length of an individual divided by its potential maximum length. We test the implementation of fractional size in demersal fish assemblages along a depth gradient in the deep sea. We use data from an extensive trawl survey at depths of 300–2030 m on the continental slope of the Rockall Trough, Northeast Atlantic, to compare changes in fractional size structure along an environmental gradient to those seen using traditional taxonomic and trait-based approaches.

3.  The relationship between fractional size and depth was particularly strong, with the overall pattern being an increase with depth, implying that individuals move deeper as they grow. Body size increased with depth at the intraspecific and assemblage levels. Fractional size, size structure and species composition all varied among assemblages, and this variation could be explained by the depth that the assemblage occupied.

4.  The inclusion of individual-level traits and population fractional size structure adds to our understanding at the assemblage level. Fractional size, or where an individual is in its growth trajectory, appears to be an especially important driver of assemblage change with depth. This has implications for understanding fisheries impacts in the deep sea and how these impacts may propagate across depths.

Item Details

Item Type:Refereed Article
Keywords:deep sea, trait-based ecology, fish community, bathymetry, deepwater fish, FishBase, functional role, Lmax, ontogeny, redundancy analysis, trait-based analysis
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Community ecology (excl. invasive species ecology)
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Assessment and management of Antarctic and Southern Ocean ecosystems
UTAS Author:Blanchard, JL (Professor Julia Blanchard)
ID Code:106279
Year Published:2016
Web of Science® Times Cited:28
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2016-02-04
Last Modified:2017-11-06

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