Inter-Research >  > Prepress Abstract

ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01037

Getting to the bottom of bycatch, a GIS-based toolbox to assess the risk of marine mammal bycatch

Ellen Hines*, Louisa S. Ponnampalam, Chalatip Junchompoo, Cindy Peter, Long Vu, Thien Huynh, Marjolaine Caillat, Andrew F. Johnson, Gianna Minton, Rebecca L. Lewison, Gregory M. Verutes

*Corresponding author:

ABSTRACT: Marine mammal bycatch poses a particular challenge in developing countries, where data to document bycatch and its effects are often lacking. Using the Bycatch Risk Assessment (ByRA) toolkit, based on InVEST open-source models, we chose 4 fieldsites in Southeast Asia with varying amounts of data on marine mammals and fishing occurrence: Trat province in the eastern Gulf of Thailand, the Sibu-Tinggi Islands and Kuching Bay, Malaysia, and Kien Giang Biosphere Reserve in southwestern Vietnam. These fieldsites have similar species of coastal marine mammals, small-scale and commercial fisheries, and support for research from universities and/or management. In Thailand and Kuching, results showed changing patterns of fishing and Irrawaddy dolphin Orcaella brevirstris habitat use across seasons, showing how bycatch risk could change throughout the year. Risk maps for dugongs Dugong dugon in peninsular Malaysia highlighted patterns of bycatch risk concentrated around a mainland fishing pier, and revealed high risk in a northern subregion. In Vietnam, first maps of bycatch risk for the Irrawaddy dolphin showed the highest risk driven by intensive use of gillnets and trawling gear. ByRA pinpointed areas of spatial and seasonal bycatch exposure, and estimated the consequence of bycatch on local species, providing managers with critical information on where to focus bycatch mitigation and meet new global standards for US Marine Mammal Protection Act and other international regulation (e.g. European Union Council Regulation 2019/1241) compliance. The toolbox, a transferable open source tool, can be used to guide fisheries management, marine mammal conservation, spatial planning, and further research.