A Workshop assessing CPUE trends and techniques used by the IOTC was held in Taipei from 30 April to 2 May 2015. The meeting covered some key aspects as to why there were differences in some of the longline fleets and addressed the following objectives that were identified in the 1st CPUE Workshop (IOTC–2013–CPUEWS01–R):
“To assess why the CPUE’s may diverge, and to identify improved methods for developing and selecting appropriate indices of abundance for Yellowfin and Bigeye Tuna. The following issues will be addressed:
1) Conduct analyses to characterise the fisheries, including exploratory analyses of the data to develop understanding of factors likely to affect CPUE.
2) Assess filtering criteria used by the primary CPC’s to test whether differences arise due to different ways of filtering the data, and rerunning the analysis with similar criteria.
3) Use the approach demonstrated by Hoyle and Okamoto (2011) in WCPFC to assess fleet efficiency by decade and then calibrate the signal to assess if we have similar trends by area.
4) Use approaches to determine targeting and then filter the data and reanalyze with respect to directed species for analysis.
5) Use operational level data in analyses of data for each fleet, and also in a joint meeting across the CPC’s.”
