Dr. Jayson Semmens and his colleagues at Tasmanian Aquaculture and Fisheries Institute (TAFI), University of Tasmania have been monitoring the movement and behaviour of two commercially important reef fish species in south eastern Tasmania. The project aims to determine the spatial and temporal extent of movement and interchange between deep and shallow water stocks and assess options for the spatial management of the fisheries. Over the past 2 years Jayson and his colleges have been following the movement of more than 60 fish tagged with acoustic transmitters and monitored their movement using a series of Vemco VR2 acoustic receivers. With each transmitter sending out up to 20 transmissions every hour the quantity of data collected over the duration of the study rapidly built up. With the aid of Eonfusion, Jayson has been able to view not only the movement and distribution of his tagged fish through time but their patterns of habitat utilization via the incorporation of bathymetry and habitat information.
Fig. 1 Spatial extent of VR2acoustic receivers (blue spheres) and their detection ranges (halos) within the study site on the east coast of Tasmania.
Fig. 2 The spatial and temporal extent of tagged fish tracks (coloured by ID).
Visualising detection frequency
With the use of the expression evaluator raw detection data can be sorted into user-defined time bins (6 hour) and cumulative frequencies calculated. The use of 4D halos around receiver locations allows the quantity of detections at each location to be visualized and the spatial distribution of tagged fish to be easily identified.
Fig. 3 Receiver locations with 4D halos (colour) indicating the quantity of detections in 6 hour time bins (size of halos represents the magnitude of detections).
Pre-constructed data flows save time with data integration and analysis tasks
With the introduction of Vemco's User Environment (VUE) software the collation of VR2 detection data is now straight forward and allows for a common output format. Pre-constructed Eonfusion dataflows allow users to visualize data outputted from the VUE software and perform a range of filtering and processing functions. Detection data can be sorted into user-defined time bins, given location offsets based on receiver detection range, filter out erroneous detections/ transmitters and construct tracks for individuals or groups of animals. For VR2W users the pre-constructed dataflow also accommodates the visualisation of receiver events logs to visualise detection efficiency, code rejection coefficients and noise quotients. Eonfusion's dataflow model allows the pre-constructed XMLs to be easily shared between Eonfusion users without the need for re-coding. The VR2 and VR2W visualization dataflows are freely available and can be obtained from our Eonfusion sales staff.
Fig. 4 Eonfusion dataflow which processes detection and event data exported from VUE. Users can easily adjust the width of time bins for visualization of detection frequency data and calculate noise quotients, detection efficiency and code rejection metrics.
Acknowledgements: Dr. Jayson Semmens and Edward Forbes -Tasmanian Aquaculture and Fisheries Institute (TAFI), University of Tasmania.
