Polychaetes as indicators of marine fish farm organic enrichment
In: Aquaculture International. Springer: London. ISSN 0967-6120; e-ISSN 1573-143X, more Also appears in:Focardi, S.; Saroglia, M. (Ed.) (2005). Animal welfare, human health and interactions with the environment. Aquaculture International, 13(1-2). Springer: Dordrecht. 173 pp., more |  |
| Keywords | Aquaculture > Marine aquaculture
Cultures > Fish culture
Environmental effects > Culture effects
Environmental impact
Fertilizers > Organic fertilizers
Organic matter > Biogenic deposits > Organic sediments
Marine/Coastal | | Author keywords | fish farm; marine sediment disturbance; organic enrichment; polychaetesassemblages |
| Authors | | Top | - Tomassetti, P.
- Porrello, S.
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| Abstract | Marine fish farms cause environmental disturbance of sediment due to uneaten food and fish faeces that accumulate on the sea bottom. These products give rise to organic enrichment followed by degradation processes; reduction of level of dissolved oxygen in the bottom water; generation of high levels of sulfides; changes of benthic assemblages and even azoic conditions. The soft bottom benthic communities and, above all, the polychaetes are considered good indicators of environmental perturbations considering their relatively fast changes in diversity and abundance and because their trophic flexibility and life-history traits are considered a pre-adaptation to the condition of disturbed habitats. The aim of the present study is to evaluate the polychaete population changes as a result of organic enrichment produced by a marine fish farm. The study was carried out on a fish farm located in the coastal water of Porto Ercole (Tyrrhenian Sea) with two submersible sea cages and a year production of 180 tonnes. The macrobenthos samples were collected during four campaigns (July and December 2001, May and October 2002). The results showed: 1) a rapid change of the assemblage located beneath the cages related to the fish biomass reared and a high dominance of the opportunistic Capitella spp.; 2) limited sediment disturbance close to cages (20-50 m); 3) no effect in the area 50 m beyond the cages. Two months after the fish harvest and thus reduction of organic enrichment, perturbated assemblages showed signals of recovery like species richness increase and reduction of opportunistic species. |
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