Abstract
The European Union-funded ECASA project (Ecosystem Approach for Sustainable Aquaculture) studied the impacts from aquaculture on ecosystems from northern Norway to Greece. The objectives of this investigation were to identify quantitative indicators of the effects of aquaculture on marine communities, and to assess their applicability over a range of ecosystems and aquaculture production systems. The study included 6 Mediterranean and 4 Atlantic sites, 7 of which produced finfish (seabream, seabass, tuna, salmon and cod), and 2 bivalve molluscs (oysters, mussels, and clams); one site produced both fish and bivalves. Cultivation methods included finfish cages, long-lines and trestles. Similar sampling methodologies were employed at the 10 study sites, obtaining sediment, hydrodynamic, and benthic faunal data. The horizontal impact from organic enrichment extended 50 m from the farms, with contradictory responses in several indicators (individual abundance, biomass) and a more consistent response of the Infaunal Trophic Index (ITI) and AZTI's Marine Biotic Index (AMBI). By means of Partial Redundancy Analysis, it was demonstrated that the environmental variables explained 53.2% of the variability in the macrofaunal variables (individual abundance, species richness, diversity, AMBI and ITI), whilst the explained variance was partialled out within three groups of variables: (i) 'hydrography' (depth, distance to farm, average current speed), which explained 11.5% of the variance; (ii) 'sediment' (Eh and percentages of silt and total organic matter), which explained 5.4%; and (iii) 'cages' (years of production and annual production), which explained 15.2%. The shared variance explained by interactions among these groups was 21.1%. These results, together with multiple regression analysis, provide an accurate assessment of the degree of impact from aquaculture. In conclusion, the use of several benthic indicators, in assessing farm impacts, together with the investigation of dynamics of the studied location, water depth, years of farm activity, and total annual production, must be included when interpreting the response of benthic communities to organic enrichment from aquaculture.
Original language | English |
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Pages (from-to) | 231-240 |
Number of pages | 10 |
Journal | Aquaculture |
Volume | 293 |
Issue number | 3-4 |
DOIs | |
State | Published - 16 Aug 2009 |
Bibliographical note
Funding Information:This investigation was supported by the European 6th Framework Programme (ECASA project, Project no. 006540), and co-funded by different institutions with each of the partners. J.G. Rodríguez was supported by the programme Torres Quevedo (Ministerio de Educación y Ciencia and Fondo Social Europeo) during the final writing of the manuscript. We want to acknowledge those people and institutions, within ECASA project, providing data for this study: José Carlos Macías (Junta de Andalucía, Spain) and Ángel Fernández (Naturepesca, Spain). This is contribution number 455 from AZTI-Tecnalia (Marine Research Division).
Keywords
- Atlantic
- Benthic indicators
- Cages
- Environmental impact
- Europe
- Fishes
- Hydrodynamics
- Marine aquaculture
- Mediterranean
- Molluscs
ASJC Scopus subject areas
- Aquatic Science