Relating species and community dynamics in an heavily exploited marine fish community

Type Article
Date 2005-12
Language English
Author(s) Duplisea Daniel1, Blanchard FabianORCID2
Affiliation(s) 1 : Fisheries & Oceans Canada, Inst Maurice Lamontagne, Mont Joli, PQ G5H 3Z4, Canada.
2 : IFREMER, RH, F-29280 Plouzane, France.
Source Ecosystems (1432-9840) (Springer), 2005-12 , Vol. 8 , N. 8 , P. 899-910
DOI 10.1007/s10021-005-0011-z
WOS© Times Cited 24
Keyword(s) Diversity stability, Species replacement, Energy flow, Emergent property, Thermodynamics, Goal function
Abstract We examined the dynamics of fish species and how they relate to species assemblage coherence in the heavily exploited Georges Bank fish community. Coherence is defined as reduced temporal variability of total assemblage biomass. We assumed that a higher degree of compensation hence coherence occurs within competitively coupled species assemblages; therefore, fisheries may directly alter the dynamics of certain targeted species sizes but assemblage structure will be relatively more stable owing to compensatory interactions. Species-sizes were grouped, based on negative covariance coupling in biomass time series from survey data. Assemblages representing benthic feeders were clearly identified by this method; furthermore, the most heavily exploited species-sizes were decoupled from other species-sizes suggesting that fisheries have diminished their potential to compensate or to be compensated for by competitive interactions. Biomass of species-sizes within known trophic guilds strongly compensated other guild-member biomass fluctuations if the diet of guild members was more specialized. This is an indication that more competitive conditions (more specialization) foster greater compensatory responses between competitors biomass fluctuations.
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