Life history traits' scoring to calculate a trawl disturbance indicator on mega- epibenthic fauna
|Author(s)||Foveau Aurélie1, Llapasset Margaux2, Desroy Nicolas3, Vaz Sandrine2|
|Affiliation(s)||1 : Université de Caen Basse-Normandie, Laboratoire Morphodynamique Continentale et Côtière, CNRS, UMR M2C 6143, 24, rue des Tilleuls, F-14000 Caen, France
2 : Ifremer, UMR MARBEC, Avenue Jean Monnet, CS 30171, F-34203 Sète Cedex, France
3 : Ifremer, Laboratoire Environnement et Ressources Bretagne Nord, 38 rue du Port Blanc, BP 70 134, F-35801 Dinard Cedex, France
|Keyword(s)||benthic fauna, disturbance, sensitivity, indicator, life history traits|
Particularly suited to the purpose of measuring the sensitivity of benthic communities to trawling, a trawl disturbance indicator (de Juan and Demestre, 2012, de Juan et al. 2009) was proposed based on benthic species life history traits to evaluate the sensibility of mega- and epifaunal community to fishing pressure known to have a physical impact on the seafloor (such as dredging and bottom trawling). The selected biological traits were chosen as they determine vulnerability to trawling: mobility, fragility, position on substrata, average size and feeding mode that can easily be related to the fragility, recoverability and vulnerability ecological concepts. Life history traits of species have been defined from the BIOTIC database (MARLIN, 2014) and from information given by Le Pape et al. (2007), Brindamour et al. (2009) and Garcia (2010). For missing life history traits, additional information from literature has been considered.
The five categories retained are life history functional traits that were selected based on the knowledge of the response of benthic taxa to trawling disturbance (de Juan and Demestre, 2012). They reflect respectively the possibility to avoid direct gear impact, to benefit from trawling for feeding, to escape gear, to get caught by the net and to resist trawling/dredging action, each of these characteristics being either advantageous or sensitive to trawling. Then, to allow quantitative analysis, a score was assigned to each category: from low vulnerability (0) to high vulnerability (3). The five categories scores were then summed for each taxon (the highly vulnerable taxon could reach the maximum score is 15) and this value may be considered as a species index of sensitivity to trawling disturbance.
The scores of 773 taxa commonly found in bottom trawl by-catch in the southern North Sea, English Channel and north-western Mediterranean were described.
|Acknowledgments||This study was partly supported by the INTERREG IV A project CHARM III (CHannel integrated Approach for marine Resource Management), the French research agency (ANR), through the project COMANCHE (Ecosystem interactions and anthropogenic impacts on great scallop populations in the English Channel) - ANR-2010-STRA-010 and France Filière Pêche (FFP), through the Galion project. The authors are grateful to all scientists and crew members who participated to the surveys and helped collecting and identify the benthic fauna.|