APPLICATION: ADCP’s for Fisheries

APPLICATION: ADCP’s for Fisheries

Teledyne RDI’s Workhorse ADCP assists in supporting Canada’s Fisheries Act.

Field photo provided by Canada’s Department of
Fisheries and Oceans

Canada’s Department of Fisheries and Oceans (Institute of Ocean Sciences, Sidney BC) is responsible for the enforcement of the Fisheries Act, which is an Act of Parliament passed in 1985. Section 35 of the Act prohibits any activity that results in the “harmful alteration, disruption or destruction of fish habitat.” As such, the Department of Fisheries and Oceans monitors sites to ensure that fish farming activities are having no significant impact on the benthic environment.

Recently, the Department of Fisheries and Oceans began a study to investigate the impact of solid wastes from net pens used in local Salmon farming. Wastes in this instance, apply to fish fecal matter, and residual food pellets that fall to the seafloor.

The scientists deployed Teledyne RDI’s 600 kHz Workhorse ADCP near an active salmon fish farm to profile the currents over time. In turn, this info was incorporated into a analytical model to predict the “foot print”, or the horizontal extent and amount of waste deposited underneath and near the net pens. The goal is to determine the flux of solid waste, which may negatively impact the benthic environment.

The ADCP was deployed in approximately 60 m of water on a mooring placed near the seafloor. The ADCP was oriented upwards, collecting profiles from near bottom to a depth that was equivalent to the base of the fish pen. The deployment cycle is typically longer than 28 days in order to quantify the currents over at least one full lunar tidal cycle.

Teledyne RDI’s ADCP is the ideal tool for this application, as Teledyne RDI’s ADCPs incorporate an “error” velocity measurement that is used to assure the quality of the data and automatically reject measurements that are biased by fish, mooring lines or falling waste. Error velocity measurements are only possible using a four-beam ADCP.