Comparison of specimen- and image-based morphometrics in Cisco

Journal of Fish and Wildlife Management
By: , and 

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Abstract

Morphometric data from fish are typically generated using one of two methods: direct measurements made on a specimen or extraction of distances from a digital picture. We compared data on 12 morphometrics collected with these two methods on the same collection of Cisco Coregonus artedi from Lake Ontario, North America, to assess the degree of bias in measurements made directly on a specimen- vs. an image-based method. We also assessed the degree of reproducibility within the image-based method by evaluating the amount of variation between different analysts for each morphometric method. Our results indicate specific morphometrics may be more prone to bias across the two methods and between analysts. Four of 12 morphometrics evaluated showed significant deviation from a 1:1 relationship that would be expected if the imaged-based method produced accurate specimen-based measurements. Pelvic fin length and pelvic–anal fin distance had the highest between-analyst variation for image-based landmarks, indicating low reproducibility for these metrics, compared with pectoral fin or total length, which had lower between-analyst variation. Although some morphometric measurements can be accurately obtained with either method, and therefore potentially used interchangeably in studies on Cisco morphology, our findings highlight the importance of considering method bias in morphometric studies that use data collected by different methods.

Publication type Article
Publication Subtype Journal Article
Title Comparison of specimen- and image-based morphometrics in Cisco
Series title Journal of Fish and Wildlife Management
DOI 10.3996/JFWM-20-029
Volume 12
Issue 1
Year Published 2021
Language English
Publisher U.S. Fish and Wildlife Service
Contributing office(s) Great Lakes Science Center
Description 8 p.
First page 208
Last page 215
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