Updated assessment of the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity to include data from 1997 to 2018
The assessment of the Prince Edward Islands (PEI) toothfish (Dissostichus eleginoides) resource carried out by Brandão and Butterworth (2018) is updated to take further data now available for 2018 into account. This update also incorporates tag-recapture data and a new basis to estimate the extent o...
| Main Authors: | , |
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| Format: | Report |
| Language: | English |
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Faculty of Science
2019
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| Subjects: | |
| Online Access: | http://hdl.handle.net/11427/30761 https://open.uct.ac.za/bitstream/11427/30761/1/FISHERIES_2019_OCT_SWG-DEM_%2034%20Updated%20Toothfish%20assessment.pdf |
| Summary: | The assessment of the Prince Edward Islands (PEI) toothfish (Dissostichus eleginoides) resource carried out by Brandão and Butterworth (2018) is updated to take further data now available for 2018 into account. This update also incorporates tag-recapture data and a new basis to estimate the extent of cetacean depredation. For the new Base case and most of the assessment sensitivities, the resource is estimated to be at a depletion (in relation to its average pre-exploitation level in terms of spawning biomass) in the 36-40% range. If the model is forced to fit the trotline CPUE indices, the estimated average pre-exploitation level in terms of spawning biomass is 19%, but this requires an assumption of very high levels of tag loss and the last two tag-recapture data points are not fitted well. |
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