title: Can we measure beauty? Computational evaluation of coral reef aesthetics.
abstract: The natural beauty of coral reefs attracts millions of tourists worldwide resulting in substantial revenues for the adjoining economies. Although their visual appearance is a pivotal factor attracting humans to coral reefs current monitoring protocols exclusively target biogeochemical parameters, neglecting changes in their aesthetic appearance. Here we introduce a standardized computational approach to assess coral reef environments based on 109 visual features designed to evaluate the aesthetic appearance of art. The main feature groups include color intensity and diversity of the image, relative size, color, and distribution of discernable objects within the image, and texture. Specific coral reef aesthetic values combining all 109 features were calibrated against an established biogeochemical assessment (NCEAS) using machine learning algorithms. These values were generated for ∼2,100 random photographic images collected from 9 coral reef locations exposed to varying levels of anthropogenic influence across 2 ocean systems. Aesthetic values proved accurate predictors of the NCEAS scores (root mean square error < 5 for N ≥ 3) and significantly correlated to microbial abundance at each site. This shows that mathematical approaches designed to assess the aesthetic appearance of photographic images can be used as an inexpensive monitoring tool for coral reef ecosystems. It further suggests that human perception of aesthetics is not purely subjective but influenced by inherent reactions towards measurable visual cues. By quantifying aesthetic features of coral reef systems this method provides a cost efficient monitoring tool that targets one of the most important socioeconomic values of coral reefs directly tied to revenue for its local population.
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Haas
authors.affiliation: ENSTA-ParisTech, Université de Paris-Saclay , Palaiseau , France.
authors.forename: Marine
authors.initials: M
authors.lastname: Guibert
authors.affiliation: The Getty Research Institute, Getty Center , Los Angeles, CA , United States.
authors.forename: Anja
authors.initials: A
authors.lastname: Foerschner
authors.affiliation: Department of Mathematics and Statistics, San Diego State University , San Diego, CA , United States.
authors.forename: Tim
authors.initials: T
authors.lastname: Co
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Sandi
authors.initials: S
authors.lastname: Calhoun
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Emma
authors.initials: E
authors.lastname: George
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Hatay
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dinsdale
authors.affiliation: Scripps Institution of Oceanography, University of California San Diego , San Diego, CA , United States.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Sandin
authors.affiliation: Scripps Institution of Oceanography, University of California San Diego , San Diego, CA , United States.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Smith
authors.affiliation: Caribbean Research and Management of Biodiversity (CARMABI) , Willemstad , Curacao ; Aquatic Microbiology, University of Amsterdam , Amsterdam , Netherlands.
authors.forename: Mark J A
authors.initials: MJ
authors.lastname: Vermeij
authors.affiliation: Department of Mathematics and Statistics, San Diego State University , San Diego, CA , United States.
authors.forename: Ben
authors.initials: B
authors.lastname: Felts
authors.affiliation: Department of Biology, College of Charleston , Charleston, SC , United States.
authors.forename: Phillip
authors.initials: P
authors.lastname: Dustan
authors.affiliation: Department of Mathematics and Statistics, San Diego State University , San Diego, CA , United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Salamon
authors.affiliation: Department of Biology, San Diego State University , San Diego, CA , United States.
authors.forename: Forest
authors.initials: F
authors.lastname: Rohwer
keywords: Aesthetics; Coral reef; Image analysis; Machine learning; Reef degradation