An update of the catchability calibration factor between the Africana with the old and the new gear, with an attempt to estimate its length-dependence

The 2004 analysis providing a catchability ratio for the Africana with the new compared to the old gear is refined and extended given additional data. The results of 1.18 (SE 0.10) for this ratio for M. paradoxus and 0.72 (SE 0.05) for M. capensis are both somewhat higher than obtained previously, primarily as a result of the additional data now available. An attempt is made at estimating the length dependence of these calibration factors, but the data are found to have insufficient information content to justify this.