Comparison of Sower Cpiii abundance estimates For Humpback Whales in area Iv with Jarpa abundance estimates

• Main Author: Branch, Trevor A
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Whaling Commission 2006
• Subjects: Butterworth; Prydz Bay
• Online Access: http://hdl.handle.net/11427/21461; https://open.uct.ac.za/bitstream/11427/21461/1/Branch_Comparison_Sower_Cpiii_2006.pdf

Estimates of abundance for humpback whales from IDCR/SOWER surveys have been provided up to and including the 1997/98 survey (Branch and Butterworth, 2001). These surveys did not cover the majority of Area IV. Data on humpback whales in Area IV were extracted from DESS for the IDCR/SOWER surveys in CPIII. Two surveys were conducted in parts of this Area: 1994/95 from 40-80°E overlapping the 70-80°E section, and the 1998/99 survey from 80-130°E covering the remainder of Area IV. Estimates were obtained separately for these two surveys. In the 1994/95 survey, the EN and ES strata covered 60- 80°E, overlapping with Area IV from 70-80°E. The Prydz Bay stratum was entirely within Area IV. There were no humpback sightings in Prydz Bay. There were only four sightings in the eastern overlapping strata. Abundance estimates for EN and ES were 53 (CV=1.01) and 84 (CV=0.53) respectively. Assuming half of the abundance was in Area IV, the total abundance in Area IV would be 68 (CV=0.51).