Occurrence of whale sharks (Rhincodon typus) based on environmental characteristics in the waters of Botubarani Beach, Gorontalo

¹ Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University, Bogor, 16680, Indonesia
² Association of Coastal and Marine Resources Management, Makassar, South Sulawesi, 90512, Indonesia

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

Abstract

Whale sharks are megafauna that inhabit tropical and warm subtropical seas as filter feeders and prey on small-sized organisms by filtering seawater. Environmental factors, such as sea surface temperature (SST), salinity (Sal), chlorophyll-a (Chl-a), ocean surface currents (currents), and the abundance of certain small marine biota, play a role in the appearance of whale sharks. This study aimed to analyze the oceanographic factors influencing whale shark appearance. Whale shark occurrence data were collected between June 2022 and July 2024. The number of whale sharks appearing in the waters of Botubarani Beach in 2022, 2023, and 2024 were 224, 337, and 219, respectively. Principal Component Analysis (PCA) was used to identify the most influential oceanographic parameters affecting whale shark occurrence. The seasonal averages of several environmental parameters in the waters of Botubarani Beach, aligned with the whale shark appearance periods, were as follows: sea surface temperature (SST) 20.03 °C, salinity 33.35 PSU, chlorophyll-a, 0.135 mg/m³; and surface current speed 0.16 m/s. PCA results indicate that the most influential environmental oceanographic parameters on whale shark occurrence at Botubarani Beach are the surface current velocity and surface chlorophyll-a concentration.