Underwater robots provide similar fish biodiversity assessments as divers on coral reefs

Type Article
Acceptance Date 2021 IN PRESS
Language English
Author(s) Maslin MathildeORCID1, Louis Silvain2, Godary Dejean KarenORCID3, Lapierre Lionel3, Villéger SébastienORCID4, Claverie ThomasORCID4, 5, Pettorelli Nathalie, Lecours Vincent
Affiliation(s) 1 : Univ. Polynesie Francaise IFREMER, ILM, IRD, EIO UMR 241 Tahiti ,Polynésie française
2 : Interactive Autonomous Dynamic Systems (IADYS) ,280 Avenue des Templiers Aubagne 13400, France
3 : Laboratory of Informatics, Robotics and Microelectronics of Montpellier (LIRMM) CNRS University of Montpellier 161 Rue Ada Montpellier 34095, France
4 : MARBEC,University of MontpellierCNRSIfremerIRD Montpellier, France
5 : Centre Universitaire de Formation et de Recherche (CUFR) de Mayotte, BP53 Dembeni, Mayotte
Source Remote Sensing in Ecology and Conservation (2056-3485) (Wiley) In Press
DOI 10.1002/rse2.209
Keyword(s) Coral reef ecosystems, fish biometrics, marine robotics, stereovision, transect surveys
Abstract

Coral reefs are under increasing threat, and the loss of reef-associated fishes providing valuable ecosystem services is accelerating. The monitoring of such rapid changes has become a challenge for ecologists and ecosystems managers using traditional approaches like scuba divers performing underwater visual censuses (UVC) or diver operated video recording (DOV). However, the use of small, low-cost robots could help tackle the challenge of such monitoring, provided that they perform at least as well as diver-based methods. To address this question, tropical fish assemblages from 13 fringing reefs around Mayotte Island (Indian Ocean) were monitored along 50 m-long transects using stereo videos recorded by a semi-autonomous underwater vehicle (SAUV) and by a scuba diver (Diver Operated stereo Video system, DOV). Differences between the methods were tested for complementary fish assemblage metrics (species richness, total biomass, total density, Shannon diversity and Pielou evenness) and for the number and size of nine targeted species. SAUV recorded on average 35% higher biomass than DOV which in turn recorded on average 12% higher species richness. Biomass differences were found to be due to SAUV monitoring larger fishes than DOV, a potential marker of human-related fish avoidance behaviour. This study demonstrates that SAUV provides accurate metrics of coral reef fish biodiversity compared to diver-based procedures. Given their ability to conduct video transects at high frequency, 100 m depth range and at a moderate cost, SAUV is a promising tool for monitoring fish assemblages in coral reef ecosystems.

Full Text
File Pages Size Access
Publisher's official version IN PRESS 12 2 MB Open access
Data S1. List of species with corresponding familly measured in that study 3 175 KB Open access
Data S2. Comparison of five diversity indices computed based on fishes recorded using DOV (diver operated video) or SAUV (semi-autonomous underwater vehicle). 1 111 KB Open access
Data S3. How altitude could have affected measurements? 3 228 KB Open access
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How to cite 

Maslin Mathilde, Louis Silvain, Godary Dejean Karen, Lapierre Lionel, Villéger Sébastien, Claverie Thomas, Pettorelli Nathalie, Lecours Vincent Underwater robots provide similar fish biodiversity assessments as divers on coral reefs. Remote Sensing in Ecology and Conservation IN PRESS. Publisher's official version : https://doi.org/10.1002/rse2.209 , Open Access version : https://archimer.ifremer.fr/doc/00697/80933/