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Linking size-based trophodynamics and morphological traits in marine fishes

Lookup NU author(s): Dr William ReidORCiD, Dr David Galvan



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley-Blackwell Publishing Ltd., 2019.

For re-use rights please refer to the publisher's terms and conditions.


The rule-of-thumb in marine trophodynamics indicates that the bigger an organism, the higher its trophic level (TROPH). This generalization leads to the assumption that fishes increase their TROPH with growth. However, a recent review showed that for many species TROPH does not increase with body size, suggesting that size-independent feeding is not rare in marine fishes. Here, we assessed some morphological traits of marine fishes that could potentially be used as indicators for the ability to vary TROPH with body size. Stable isotope values of nitrogen were used as a proxy TROPH. The specific objectives were: (1) to evaluate the relationship between the oral gape and the trophodynamic trend; and (2) to quantify the relevance of 11 external morphological traits in determining the size-based trophodynamics. We used random forest models to identify the morphological traits that would help predict which species would have the potential to increase TROPH with growth, and which would have not. The selected traits included the pelvic fin relative position, the dorsal fin shape, total length and relative mouth size. Our results also showed a marked relationship between the rate of increase of the oral gape and TROPH. The analyses presented here provide the first comprehensive and quantitative review aiming at linking the trophodynamics of marine fishes with external morphological traits.

Publication metadata

Author(s): Rios MF, Venerus LA, Karachle PK, Reid WDK, Erzini K, Stergiou KI, Galvan DE

Publication type: Article

Publication status: Published

Journal: Fish and Fisheries

Year: 2019

Volume: 20

Issue: 2

Pages: 355-367

Print publication date: 01/03/2019

Online publication date: 02/01/2019

Acceptance date: 29/11/2018

Date deposited: 19/12/2018

ISSN (print): 1467-2960

ISSN (electronic): 1467-2979

Publisher: Wiley-Blackwell Publishing Ltd.


DOI: 10.1111/faf.12347


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