Obtaining a standardised CPUE series for toothfish (Dissostichus eleginoides) in the Prince Edward Islands EEZ calibrated to incorporate both longline and trotline data over the period 1997-2012
The previous GLMM standardisation approach for PEI toothfish (Spanish) longline CPUE data is extended to include data for the 2011-2012 seasons and the same approach is applied to trotline CPUE data for the 2008–2012 period. CPUE data from a research program carried out in 2012 in which longline and...
| Main Authors: | , |
|---|---|
| Format: | Report |
| Language: | English |
| Published: |
University of Cape Town
2012
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/11427/19690 https://open.uct.ac.za/bitstream/11427/19690/1/Brand%c3%a3o_Obtaining_a_standardised_2012.pdf |
| Summary: | The previous GLMM standardisation approach for PEI toothfish (Spanish) longline CPUE data is extended to include data for the 2011-2012 seasons and the same approach is applied to trotline CPUE data for the 2008–2012 period. CPUE data from a research program carried out in 2012 in which longline and trotline sets were paired to within three nautical miles and a period of two weeks is analysed to obtain a calibration factor for longlines and trotlines. A model is then fitted to combine the two individual standardised CPUE series and the calibration factor to obtain a “calibrated” longline CPUE series (incorporating both longline and trotline information) and an estimate of the calibration factor. This indicates a drop of about 44% in standardised CPUE in 2012 compared to the immediately preceding years; however it must be noted that the data in 2012 is available only until August. |
|---|