Eyes on the size: accuracy of visual length estimates of white sharks, Carcharodon carcharias.

ABSTRACT: Visual estimates have been used extensively to determine the length of large organisms that are logistically challenging to measure. However, there has been little effort to quantify the accuracy or validity of this technique despite inaccurate size estimates leading to incorrect population assessments and misinformed management strategies. Here, we compared visually estimated total length measurements of white sharks, Carcharodon carcharias, during cage-diving operations with measurements obtained from stereo-video cameras and assessed the accuracy of those estimates in relation to suspected biases (shark size, and observer experience and gender) using generalized linear mixed-models and linear regressions. Observer experience on board cage-diving vessels had the greatest effect on

SUBMITTER: May C 

PROVIDER: S-EPMC6549950 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature