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SC/69B/HIM/21
Resource ID
22112
Access
Open
Document Number
SC/69B/HIM/21
Full Title
Developing multi-method and multi-taxa approaches to bycatch risk assessment in the Arabian Sea
Author
Sarah Farinelli, Andrew Willson, Manjula Tiwari, Gianna Minton, Ammar Al Aamari, Ellen Hines
Authors Summary
Willson presented the development of multi-method and multi-taxa approaches to risk assessment of humpback whales and loggerhead turtles (Caretta caretta) from artisanal fisheries in the Arabian Sea. Part of this work was funded from the IWC SC. Threats from artisanal fisheries have previously been identified as a regional concern throughout the range of both species. Interaction of these populations with fishing gear remains a mystery due to the challenge in collection of data from remote and inaccessible fisheries. Authors used the Bycatch Risk Assessment (ByRA) Toolbox as a GIS platform from which to conduct the risk assessment (Hines et al. 2020). Raster stress layers of artisanal fishing vessel density were developed from vessel counts undertaken during cetacean surveys and freely accessible Sentinel 2 satellite imagery over a limited study area in the Gulf of Masirah, Oman. The ByRA approach combined the stress layer with kernel density maps from satellite telemetry data representing habitat utilisation. The final step of the risk assessment process applied an exposure/ consequence ranking model to the mapped features accounting for the specific influences that species attributes and fisheries interactions were projected to have on the populations. The remote sensing methods proved successful and demonstrated humpback whales and loggerhead turtles had similar exposure/ consequence values, but that the whales were at higher risk within the limited confines of the study area. The next phase of the study will focus on development of automated detection of vessels from satellite imagery and superimposing the vessel detections with effort metrics from remote electronic monitoring studies of vessels in the same study area.
Publisher
IWC
Publication Year
2024
Abstract
Understanding the interaction between fisheries and non-target species is a key component of marine resource management initiatives. Evidence indicates that Arabian Sea humpback whales (Megaptera novaeangliae) and loggerhead turtles (Caretta caretta), both considered threatened on the IUCN Red List, have been associated with fisheries interactions in the Arabian Sea. Artisanal fisheries dominate the fisheries sector in the Arabian Sea, and Oman?s artisanal fleet accounts for 99% of the fishing fleet in the country. Government and community stakeholders in Oman have identified bycatch risk assessment as a priority for the management of these species. However, fisheries monitoring remains a challenge due to the remote locations and harsh conditions in which they operate. Here, we present the first phases of development of a method to assess bycatch in the Arabian Sea using a multi-method approach to bycatch assessment using the Bycatch Risk Assessment (ByRA) Toolbox, which is supported by vessel surveys and satellite imagery. This approach will eventually also incorporate the use of remote electronic monitoring and local ecological knowledge. By integrating these methods, we aim to overcome the time and spatial sampling limitations associated with each method when used independently for conducting risk assessments. The objective of the method development is to identify solutions for risk assessments across larger fleet sizes, vessel types, and ocean areas. This approach will lead to the extension of the application of ByRa to testing the influence of different fisheries management scenarios on bycatch within the western Arabian Sea and to other high priority bycatch risk areas where data from artisanal fishing fleets is limited.