Spatio-Temporal Dynamics of Exploited Groundfish Species Assemblages Faced to Environmental and Fishing Forcings: Insights from the Mauritanian Exclusive Economic Zone

Type Article
Date 2015-10
Language English
Author(s) Kide Saikou Oumar1, 2, Mante Claude2, Dubroca Laurent3, Demarcq Herve4, Merigot Bastien5
Affiliation(s) 1 : Inst Mauritanien Rech Oceanog & Peches, Lab Biol & Ecol Organismes Aquat, Nouadhibou, Mauritania.
2 : Aix Marseille Univ, Mediterranean Inst Oceanog, Marseille, France.
3 : IFREMER, F-14520 Port En Bessin Huppain, France.
4 : IRD, UMR MARBEC 9190, Ctr Rech Halieut Mediterraneenne, Sete, France.
5 : Univ Montpellier, UMR MARBEC 9190, Ctr Rech Halieut Mediterraneenne, Sete, France.
Source Plos One (1932-6203) (Public Library Science), 2015-10 , Vol. 10 , N. 10 , P. -
DOI 10.1371/journal.pone.0141566
WOS© Times Cited 7
Abstract Environmental changes and human activities can have strong impacts on biodiversity and ecosystem functioning. This study investigates how, from a quantitative point of view, simultaneously both environmental and anthropogenic factors affect species composition and abundance of exploited groundfish assemblages (i.e. target and non-target species) at large spatio-temporal scales. We aim to investigate (1) the spatial and annual stability of groundfish assemblages, (2) relationships between these assemblages and structuring factors in order to better explain the dynamic of the assemblages’ structure. The Mauritanian Exclusive Economic Zone (MEEZ) is of particular interest as it embeds a productive ecosystem due to upwelling, producing abundant and diverse resources which constitute an attractive socio-economic development. We applied the multi-variate and multi-table STATICO method on a data set consisting of 854 hauls collected during 14-years (1997–2010) from scientific trawl surveys (species abundance), logbooks of industrial fishery (fishing effort), sea surface temperature and chlorophyll a concentration as environmental variables. Our results showed that abiotic factors drove four main persistent fish assemblages. Overall, chlorophyll a concentration and sea surface temperature mainly influenced the structure of assemblages of coastal soft bottoms and those of the offshore near rocky bottoms where upwellings held. While highest levels of fishing effort were located in the northern permanent upwelling zone, effects of this variable on species composition and abundances of assemblages were relatively low, even if not negligible in some years and areas. The temporal trajectories between environmental and fishing conditions and assemblages did not match for all the entire time series analyzed in the MEEZ, but interestingly for some specific years and areas. The quantitative approach used in this work may provide to stakeholders, scientists and fishers a useful assessment for the spatio-temporal dynamics of exploited assemblages under stable or changing conditions in fishing and environment.
Full Text
File Pages Size Access
Publisher's official version 21 6 MB Open access
R script and data files. 42 KB Open access
Description of the STATICO method following Thioulouse et al. (2004). 21 KB Open access
Fish assemblages, with species list, identified by mean of average linkage classification (UPGMA, see methods section), with their sedimentary types and depth stratum. 26 KB Open access
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