Measuring congruence between electronic monitoring and logbook data in Australian Commonwealth longline and gillnet fisheries

EM Info Admin

Published March 22, 2019
  • Timothy J. Emery, Rocio Noriega, Ashley J. Williams and James Larcombe

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    Abstract

    Electronic monitoring (EM) has the capacity to collect fisheries-dependent data to support 
fisheries management decision-making. Following successful pilot studies, EM was 
introduced into several Australian Commonwealth fisheries in 2015, including the Eastern 
Tuna and Billfish Fishery (ETBF) and the Gillnet, Hook and Trap (GHAT) sector of the 
Southern and Eastern Scalefish and Shark Fishery (SESSF).

    We compared two years of EM 
analyst and fisher-reported logbook data from the ETBF and GHAT sector to examine the 
level of congruence in reporting of both retained and discarded catch and protected species 
interactions. In general, congruence between EM analyst and fisher-reported logbook data 
in both the ETBF and GHAT sector was higher for retained than for discarded catch, and 
the ETBF had a higher level of data equivalency than the GHAT sector. Fishery-wide 
estimates of congruence, however, concealed a large amount of variation among individual 
and groups of species. EM analyst and fisher-reported logbook data were highly congruent 
for some species (e.g. tunas, swordfish and gummy shark), but for others there were clear 
taxonomic (e.g. escolar and rudderfish), identification (e.g. sharks, marlins) and reporting 
(e.g. draughtboard shark and elephantfish) issues, which reduced overall congruence.

    There 
was evidence of increased congruence through time, particularly for discarded bycatch 
species in the GHAT sector, due presumably to increased manager feedback and 
communication with fishers on their logbook reporting. While EM analyst and fisher-reported logbook interactions with protected species in the GHAT sector were equivalent, 
this was not the case for species other than seabirds in the ETBF. In the ETBF, a greater 
number of interactions were reported by fishers in their logbooks, suggesting a need to 
modify existing or install additional EM technology to improve on-board vision for the EM 
analyst. It is important to review the performance of any integrated EM system through time 
to ensure it is fulfilling the data requirements for the fishery and meeting the overall 
objectives of the program. 


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