How to spot the Thresher shark when scuba diving
Alopias
Found nearly worldwide in tropical and temperate oceanic and coastal waters. Bigeye Threshers (A. superciliosus) are circumglobal in warmer waters. Common Threshers (A. vulpinus) are also widespread, including cooler temperate waters. Pelagic Threshers (A. pelagicus) are primarily Indo-Pacific. They inhabit open ocean but also come closer to shore.
Malapascua, Philippines is the most famous location, with sightings possible year-round, peaking during the dry season (Dec-May often cited as best, sometimes narrowed to Apr-June). Encounters typically occur during early morning dives (dawn).
Wide range from temperate (e.g., 16°C) to tropical, depending on species and location.
Known for visiting specific seamounts or reefs that act as "cleaning stations." Monad Shoal in Malapascua (depth ~20-30m) is the prime example. Divers usually position themselves quietly on the edge of the shoal before sunrise to wait. They are pelagic and can be found deep, but cleaning stations bring them into recreational dive depths. Respectful distance and calm behaviour are essential.
Worldwide observation of the Alopias
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Data sources
- Photos: Wikimedia Commons
- Distribution and specie data: GBIF (Global Biodiversity Information Facility)
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