Assessing trace-element indicators of benthic organic enrichment associated with aquaculture activities
Aquaculture wastes, such as faeces or uneaten food, can accumulate beneath and near farm sites. In the near-field, this accumulation is predictable using depositional modelling tools such as DEPOMOD, and the organic enrichment effects associated with this deposition are well known and managed to ensure environmental sustainability. However, the far-field effects that may be associated with the release of aquaculture waste material are poorly understood, partly because it is difficult to accurately predict where wastes will be dispersed. Additionally, once wastes are moved from the immediate vicinity of a farm site it is difficult to distinguish between deposits coming from farm activities, other industrial sources and naturally occurring materials.
To monitor, and if necessary, regulate, the far-field effects of aquaculture wastes, it is necessary to be able to identify where wastes are transported and what material originates from farm sources. A limited number of sensitive detection tools (sediment free sulfides and geonormalized trace-metals) are currently available to environmental monitoring programs for making such identifications. Research to date, focused on trace-metal assessments at a variety of aquaculture sites, has shown that aquaculture waste material (fish feed and faeces) has a trace-metal signature that can be distinguished from that of naturally-occurring trace-metals. It is proposed that the geonormalization of trace-elements may identify depositional "hot spots" and track transport pathways to determine the fate of farm waste material. This approach could help to identify areas where wastes would accumulate in the far-field and ultimately, inform aquaculture management in the spatial design of monitoring programs.
As a first step towards conducting a robust regional impact assessment (longer-term research goal), this PARR project will focus on obtaining, formatting, and running a preliminary analysis on archived benthic data sets previously collected by the British Columbia Ministry of the Environment and Fisheries and Oceans Canada. These datasets will support a region-wide assessment of aquaculture-derived trace-metal signature under various oceanographic, bathymetric and operational settings. This geonormalization approach may be adopted to assess the fate of aquaculture wastes in the far-field and across a range of environmental settings.
2012 - 2014
Pacific: Vancouver Island West Coast
Research Scientist, Fisheries and Oceans Canada (FOC), DFO-UBC Centre for Aquaculture and Environmental Research (CAER)
4160 Marine Drive, West Vancouver, B.C., Canada V7V 1N6
Tel.: (604) 666-8537
Fax: (604) 666-3497
Bernie Taekema, DFO-Pacific Region
Kerra Hoyseth, DFO-Pacific Region
March Klaver, DFO-Pacific
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