Changes in benthic sediment conditions under an Atlantic salmon farm at a deep, well-flushed coastal site

Abstract

Along the Norwegian coastline, it is predicted that salmonid aquaculture will rapidly expand in the coming years, exceeding current production levels of 1.3 million t in 2012. This will result in increased interactions with both local and regional environments, thus more knowledge is urgently needed to better risk-manage a rapid expansion. We investigated changes in the benthic sediment condition in association with an Atlantic salmon farm sited at a deep, well-flushed coastal site in western Norway. Benthic fluxes of O 2 , total carbon dioxide (TCO 2 ) and NH 4 + intensified over the production cycle, when farming activity and the sedimentation of carbon and nitrogen was at its maximum. During the sampling campaign, benthic fluxes of O 2 , TCO 2 and NH 4 + at the farming location were higher than those measured at a nearby reference location. Stimulation of benthic fluxes over the production cycle at the farming location were most likely driven by changes in benthic faunal community structure, abundance and biomass. High abundances of opportunistic species (i.e. Capitella capitata, Heteromastus filiformis, Paramphinome jeffreysii, Abra nitida and Thyasira sarsii) dominated the farming location, whilst the sediment biogeochemistry was stable throughout the study period at both locations. However, despite differences in benthic fluxes and fauna structure over the production cycle, the input of organic carbon and nitrogen did not exceed the mineralisation capacity of a deep, well-flushed, fish farming location.

Spatiotemporal Dispersal and Deposition of Fish Farm Wastes: A Model Study from Central Norway

“…One of the main limiting factors for further growth of the mariculture sector is the availability of good locations (Hersoug, 2013). In Norway the number of concessions has decreased in recent years (Gullestad et al, 2011;Bannister et al, 2014). It is therefore likely that with the present cultivation technology the average production at each location will further increase, with an ensuing increase in the local release of particulate and dissolved organic matter leading to a potentially higher impact on the pelagic and benthic (Mazzola et al, 2000;Carroll et al, 2003;Kalantzi and Karakassis, 2006).…”

Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges

“…Organic waste produced in fish farms negatively impacts aquatic ecosystems by modifying water biochemistry and ecological interactions (Troell et al 2014). Particulate organic matter and dissolved inorganic nutrients, especially nitrogen (N) and phosphorus (P) forms, can promote water eutrophication and dramatically change sediment chemistry and associated benthic biodiversity (Sanz-Lázaro et al 2011, Sarà et al 2011, Valdemarsen et al 2012, Bannister et al 2014. In this way, new integrative, non-linear production methods are necessary to reduce the ecological impact of fish farms.…”

Potential environmental risks associated with biofouling management in salmon aquaculture

“…, or 350 to 400 t farm −1 an nually (Taranger et al 2013, Bannister et al 2014. Depending on currents, particulate feed and faecal matter arising from fish farms can be de posited over distances of up to ~1 km and may interfere with natural biogeochemical and trophic processes (Kutti et al 2007, Valdemarsen et al 2012, Callier et al 2013.…”