The effect of sample size on the observed length distribution of Antarctic krill

The appropriate sample size for krill length measurement was raised during the WG-SISO-17 and WG-EMM-17 meetings.In this paper, the question was investigated through a case study based on the length data collected by scientific observers onboard the Chinese krill fishing vessel Fu Rong Hai during the 2015/2016 fishing season. The variation of statistical property of krill length distribution with different sample size was evaluated using simplebootstrap resampling method. Four typical patterns of krill length distribution, including unimodal, bimodal, left-skewed and right-skewed unimodal, were investigated, respectively.Results indicated thatwhenthe sample size was higher than 100 individuals,the mean and coefficient of variance (CV) of the krill length distribution mightnot be very sensitive to the size of the samples.