The Centre for Environment, Fisheries and Aquaculture Science (Cefas) has collaborated with marine robotics specialist Liquid Robotics to successfully trial an innovative technique for counting schools of fish. The trial formed part of the UK NERC/Defra funded AlterEco project which seeks to develop an innovative framework for assessing marine ecosystem functioning in continental shelf seas.
The partnership saw the firms deploy, test and recover a remotely piloted wave glider (WG) – a wave-powered mobile data-gathering platform – which was adapted to allow scientists to collect high quality fisheries acoustics data. The WG was deployed in the central North Sea and spent 41 days at sea covering a 64km area, collecting high resolution acoustic data on organisms within its range. Scientists are now using this information to learn more about zooplankton and fish populations around the UK. Preliminary results suggest evidence has been captured which will reveal more about the day-night vertical migrations of schools of fish and zooplankton.
The WG also gathered data on the physical properties of the sea surface including salinity, temperature, oxygen, fluorescence, turbidity and solar irradiance data at five-minute intervals. These data will be used to study the oceanographic features of the area.
A second AlterEco mission is planned to start in mid-August with engineers investigating the potential of adding an echo-sounder to the WG, enabling it to transmit summary data over a satellite communications link.
David Pearce, Cefas head of profession, marine observations systems, and in command of this mission, said: "These autonomous vehicles could eventually take over elements of ship-based monitoring of the fish and zooplankton community by being able to identify these components of the food chain from the acoustic data alone and thus saving money by reducing the durations of ship-intensive surveys."