The Spatial Variation of Acoustic Water Column Data and Its Relationship with Reef-Associated Fish Recorded by Baited Remote Underwater Stereo-Videos off the Western Australia Coast

Marcela Montserrat Landero Figueroa,Iain M Parnum,Miles J G Parsons,Benjamin J Saunders

doi:10.3390/jmse10010052

Marcela Montserrat Landero Figueroa, Iain M Parnum + Show 2 more

Open Access

https://doi.org/10.3390/jmse10010052

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Abstract

Spatially explicit information on coral fish species abundance and distribution is required for effective management. Nonextractive techniques, including echosounders and video census, can be particularly useful in marine reserves where the use of extractive methods is restricted. This study aimed to investigate the possibility of combining echosounders and baited remote underwater stereo-videos (stereo-BRUVs) in providing more holistic information on the distribution of demersal and semidemersal reef-associated fish. The spatial distribution of fish biomass was assessed using both methods in two small areas, one in Cockburn Sound (CS), a temperate body of water, and the other in the tropical waters of the Ningaloo Marine Park (NMP). The results showed high correlations between the acoustic and stereo-BRUV data in CS, suggesting the potential use of both for a better estimation of biomass in the area. The results for the NMP showed weaker correlations between the two datasets and highlighted the high variability of the system. Further studies are required, but our initial findings suggest a potential benefit of combining both techniques in the reef-associated fish distribution assessment.

Highlights

Coral reefs are the most biodiverse ecosystems in the ocean, providers of a variety of environmental services, and home to a diverse number of species of fish [1,2,3]
This study aimed to investigate the possibility of combining stereo-BRUVs and echosounder data in providing more holistic information of the distribution of demersal and semidemersal fish with a general hypothesis: The spatial distribution of biomass captured by stereo-BRUVs is highly correlated with the spatial distribution of the acoustic biomass estimated based on the echosounder
A similar pattern was observed for the number of acoustic targets in the water column, while for the demersal layer, higher the number of acoustic targets in the water column, while for the demersal layer, higher values between 14 and 41 acoustic targets were found in the central part of the study values between 14 and 41 acoustic targets were found in the central part of the study site (Figure 3c)

Summary

Introduction

Coral reefs are the most biodiverse ecosystems in the ocean, providers of a variety of environmental services, and home to a diverse number of species of fish [1,2,3]. Coral reefs and their codependent species are increasingly threatened by anthropogenic impacts at both a local (e.g., overfishing) and global scale (e.g., global warming) [4]. Traditional management strategies for coral-reef fisheries, including catch quotas, size restrictions, or seasonal closures, have had variable levels of success. This has resulted in the implementation of marine protected areas (MPAs) as the leading tool for coral reef fish diversity conservation [5]. Sustainable management of coral reef fishes requires spatially explicit information on their abundance and distribution at scales relevant for MPA monitoring [7]. Nonextractive methods are required to collect reef fish data on MPAs

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