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SC/69A/ASI/15/Rev1
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Resource ID
19949
Access
Open
Document Number
SC/69A/ASI/15/Rev1
Full Title
Addressing recommendations by the IWC Scientific Committee to improve estimates of abundance of the franciscana dolphin
Author
Federico Sucunza, Daniel Danilewicz and Alexandre N. Zerbini
Authors Summary
Estimates of abundance of the franciscana dolphin (Pontoporia blainvillei) have been under by the IWC Scientific Committee (SC) as part of the review of the status of the franciscana by the Committee following the process established by the working group on Abundance Estimates, Status of Stocks and International Cruises (ASI). As part of the review process, the SC provided several suggestions to improve correction factors (CFs) to estimate density of franciscana dolphins as well as to improve estimates of abundance of this species and agreed the following tasks should be performed before the review of the status of the franciscana is completed by the Committee. CF for visibility and group size bias was revised following the recommendations of the SC at 4.76 (CV=0.25). Estimates of abundance were reviewed for FMA Ia (N=1,183, CV=0.76) and Ib in 2011 (N=1,590, CV=0.53) and 2017 (N=1521, CV=0.47) and we propose they are endorsed as Category 1 by the Committee. The estimate for FMA II corrected for group size bias using the 1.36 (CV=0.11) factor is 9,284 (CV = 0.28). We propose this estimate be elevated to Category 1A. The revised estimate for FMA III corrected for visibility and group size bias is 9,437 (CV = 0.34).
Publisher
IWC
Publication Year
2023
Abstract
Estimates of abundance of the franciscana dolphin (Pontoporia blainvillei) have been under by the IWC Scientific Committee (SC) as part of the review of the status of the franciscana by the Committee following the process established by the working group on Abundance Estimates, Status of Stocks and International Cruises (ASI).