Assessment of long term change in sediment condition after organic enrichment: defining recovery

• Published in: Marine pollution bulletin Vol. 49; no. 1; pp. 79 - 88
• Main Authors: Macleod, Catriona K., Crawford, Christine M., Moltschaniwskyj, Natalie A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2004; Elsevier
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Aquaculture; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Environmental assessment; Environmental Monitoring; Fundamental and applied biological sciences. Psychology; General aspects; Geologic Sediments - chemistry; Invertebrates; Marine; Monitoring; Organic enrichment; Population Dynamics; Salmo salar; Sediment recovery; Video; Water Pollutants - analysis; Australia; Tasmania; Oceania; Australia, Tasmania; PSE, Australia, Tasmania; Environmental assessment; Organic enrichment; Sediment recovery; Video; Monitoring; Aquaculture; Salmonidae; Organic matter; Salmo salar; Sediments; Long term; Time variation; Medium enrichment; Vertebrata; Restoration; Pisces; Pisciculture
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2004.01.010

Sediment condition at an Atlantic salmon (
Salmo salar) culture site in S.E. Tasmania, Australia was evaluated to determine the rate and extent of recovery after removal of farmed fish. By local standards the cage sediment at the start of this survey was markedly degraded but comparison with results from impact studies in Scotland, Canada and Norway suggests that the sediments were considerably less impacted than in northern temperate areas. The impact at the cages diminished rapidly with both time and distance; after only 2 months conditions were markedly improved. The macrobenthos indicated a slower recovery than chemical measures, after 36 months the benthic faunal community structure under the cages still differed from reference conditions even though other sediment measures had recovered. This study highlighted two other key issues in relation to monitoring and management of sediment recovery. First, techniques used to determine impact may not be appropriate for evaluation of recovery. Second, establishment of local baseline standards is extremely important to ensure appropriate evaluation of both impact and recovery.