Spatial modeling of whale shark protection using the marxan method in Saleh Bay, West Nusa Tenggara

¹ Marine Technology Study Program, Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University, Bogor, 16680, Indonesia
² Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University, Bogor, 16680, Indonesia
³ National Research and Innovation Agency (BRIN), KST Soekarno, Cibinong, Bogor, 16911, Indonesia
⁴ Aquaculture Biology and Fisheries Ecology Group, Wageningen University and Research, The Netherlands

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Saleh Bay is a recurring aggregation area for whale sharks (Rhincodon typus). This study applied the Marxan decision-support tool to identify spatial conservation priorities based on whale shark sighting records and selected environmental and anthropogenic proxies, without explicitly modeling habitat suitability or preference. The inputs included sea surface temperature, chlorophyll-a concentration, whale shark occurrences, fishing net distribution, and indicators of human activities. Three zoning scenarios, with increasing conservation targets, were evaluated. The scenario with the highest target identified a core priority area of 102,831.29 ha (50.13% of the study area), exceeding that of the lower-target scenarios. The resulting priority zones reflect the spatial patterns of whale shark aggregation and associated environmental conditions under the current observation data. These findings are intended to inform marine spatial planning by providing a precautionary basis for conservation decision making while accommodating existing coastal uses.