Aquaculture Site Monitoring

Hughes Clarke, Wildish (DFO) and Tlusty(NEA)

(Funded through CFI, Prov. NB and Simrad)

A joint research project between DFO science and the OMG has followed up on earlier OMG results in deploying high frequency multibeam sonars immediately adjacent to active salmon mariculture sites. The original surveys in Bay D’Espoir, NF indicated that the build up and redistribution of organic-rich salmon farm waste (excess food and excrement) could be accurately monitored using the backscatter and bathymetric imaging capability of a Simrad EM3000S.

Most recent results (October 2000) in the Letang and Bliss Harbour areas of New Brunswick (see EM3000 backscatter image to the left), indicate that the build of the material is strongly influenced by the site location with respect to the tidal current activity in the area. Whilst the most favoured sites are in sheltered bays (for hardware preservation reasons) it is clearly these sites in which the most negative impact is observed on the bottom benthos.

A multi year repeat monitoring program is now planned to assess the temporal variability of the acoustic signature of the salmon farming. By observing both active and abandoned sites, the long-term effect of this critically important industry can be observed.