Report on analyses of the 2016/2019 PNA FAD tracking programme

This paper presents analyses of the PNA’s fish aggregating device (FAD) tracking programme including: a description of the data processing required; a description of the spatio-temporal distribution of buoy deployments and number of FADs at sea; FAD densities including a correction procedure using ocean-current driven simulations; matching positions within FAD tracking and VMS data; and an analysis of the fate of FADs. As FADs drift in the ocean, the associated electronics can be replaced making it difficult to follow individual FADs, therefore for the purposes of this analysis we followed the satellite buoys, unless otherwise stated.
To better distinguish drifting buoys from those on board vessels, data were analysed using a Random Forest model to identify the drifting at-sea section of each buoy trajectory, and at the same time identify deployment positions. In addition, as for previous years, the data received by PNA are modified by fishing companies prior to submission, for example information outside PNA Exclusive Economic Zones (EEZs) may be removed (i.e., “geo-fenced”), which could introduce a bias to the analyses. After undertaking the correction procedure, the filtered dataset consisted of 21.9 million transmissions from 41,000 unique buoys and covered the period from 1st January 2016 to 30th May 2019...