Characterization of the fish shoals depending on bottom variables in various ecosystems [résumé]

2024

Colloque

Mouget A., Acou A., David V., Feunten E., Thiriet P., Perrot Yannick, Sarre A., Diogoul N., Vehlo F., Koné V., Brehmer Patrice

Working Group in Fisheries Acoustics Science and Technology (WGFAST)

Copenhague : CIEM, 2024, p. 32

ICES. Working Group of Fisheries Acoustics, Science and Technology (WGFAST), Plouzané (FRA), 2024/04/09-2024/04/12

Fisheries acoustic tools, widely used in open ocean contexts, have become more common in shallow waters, but there is still a lack of information in ultra-coastal area (<15 m depth). Additionally, environmental parameters beyond bathymetry, such as seafloor terrain, likely play significant roles for biocenose aggregation, distribution and diversity in shallow waters. Pelagic fish shoals, aggregations of fish, are sensitive to environmental factors and can serve as proxies to monitor ecosystems. Various physical parameters, such as time of day and distance to coast, influence fish distribution. This study aims to investigate the impact of topographic variables on pelagic shoals across off-shore to coastal areas (5-500 m depth). Two datasets from French Brittany and West African coasts were analyzed to highlight global patterns and local specificities. The analysis focuses on coastal and shallow waters, aiming to identify common patterns across systems while recognizing potential differences, particularly in upwelling systems. This study highlight the importance of ultra-coastal area, with a high relative biomass (Sv). The analyze of common patterns revealed the importance of bathymetry in all studied systems. Some other topographic variables have been discovered as important in many systems. However, each system presents its own specificities, with similarity between systems with or without upwelling.

Aquaculture [040AQUAC] ; Ecosystèmes [082ECOSYS]

Fonds IRD [F B010091527]

fdi:010091527