Results of the feasibility study on biopsy sampling and satellite tagging of Antarctic minke whales under NEWREP-A
Genta Yasunaga, Kenji Konishi, Tatsuya Isoda, Tsutomu Tamura
International Whaling Commission
This paper presents the results of the feasibility studies of biopsy sampling and satellite tagging of Antarctic minke whales under the NEWREP-A, which were conducted between the 2015/16-2017/18 austral summer seasons. The feasibility studies were conducted considering the recommendations of the NEWREP-A review workshop. First the Success Proportions of biopsy and whale (lethal) sampling was estimated, then the efficiency between the two approaches were assessed using a Generalized Linear Model (GLM) considering the following response variables: sampling methods (biopsy and whale sampling), Beaufort scale, visibility and sampling area. The explanatory variable in the best fitted model included only ‘sampling method’, suggesting that environmental variables had not a significant effect. The estimated Success Proportions for biopsy sampling (0.434±0.050) were much lower than that for whale (lethal) sampling (0.967±0.006). Furthermore, the time spent on biopsy sampling was approximately three times longer than that spent on lethal sampling. Therefore the efficiency of biopsy sampling is much lower than that of lethal sampling for Antarctic minke whales in the NEWREP-A. At this stage biopsy sampling of Antarctic minke whales is not a feasible technique that could contribute to the NEWREP-A research objectives. Given these results, no additional experiments on biopsy sampling will be conducted in future NEWREP-A surveys. However additional biopsy samples could be collected opportunistically to increase the sample size and then consider other variables in the statistical analysis in the future. Satellite tagging can respond some specific questions with a moderate number of whales tagged, therefore additional tagging experiments will be conducted in the future focused on responding to such specific research questions.