Potential SLAs for West Greenland fin whales testing against the agreed evaluation trials.
This paper presents four potential SLAs for West Greenlandic fin whales. The proposed SLAs are based on a weighted-average interim SLA which uses all abundance estimates, but earlier abundance estimates are down-weighted compared to more recent ones. An adjustment to the multiplier of the abundance...
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| Format: | Report |
| Language: | English |
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Faculty of Science
2018
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| Online Access: | http://hdl.handle.net/11427/30707 https://open.uct.ac.za/bitstream/11427/30707/1/SC_67B_AWMP_15.pdf |
| Summary: | This paper presents four potential SLAs for West Greenlandic fin whales. The proposed SLAs are based on a weighted-average interim SLA which uses all abundance estimates, but earlier abundance estimates are down-weighted compared to more recent ones. An adjustment to the multiplier of the abundance estimate in the interim SLA is applied which depends on the trend of the abundance indices. Three candidate SLAs are tuned to achieve 1.0, 0.9 and 0.8 for the conservation statistic (D10) at the lower 5 percentile for the Influx hypothesis trial GF34-1B with a MSYR1+ of 1% and the middle need envelope (B). The fourth SLA attempts to provide near complete satisfaction of the conservation performance criterion and meet need satisfaction for all evaluation trials excluding the Influx hypothesis trials. To achieve a lower 5 percentile of the D10 statistic of one for the GF34-1B trial, the lower 5 percentile of need satisfaction (N9 over 20 and 100 years) is never met (SLA1.0). Dropping the D10 statistic to 0.8 for this trial improves need satisfaction by all other trials without sacrificing conservation performance (except for Influx hypothesis trials at MSYR1+= 1%). |
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