How deep do whale sharks really dive?

New research into how deep whale sharks dive reveals surprising insights into their behaviour and the hidden workings of the ocean, highlighting why understanding these gentle giants matters more than ever.

Whale sharks typically inhabit the epipelagic layer, spending around 95% of their time in this uppermost layer of the ocean. But occasionally, to fill that other 5% of their time, they make deep dives to the Bathypelagic zone, sitting at about 1000 meters to 4000 meters deep. These trips are driven by biological needs rather than joy trips or holidays to get away. Foraging is the main one, whale sharks target prey such as deep-sea squid and zooplankton, residents only to this layer of the ocean.

The second reason for their deep-sea treks is called thermoregulation. Dives into colder water help regulate body temperatures, which is especially necessary in tropical waters where temperatures can rise to 21 degrees - even when temperatures can range from 2 degrees to below freezing, quite the thermal shock!

Navigation in the ocean is no simple feat, and in order to keep well-coordinated, whale sharks take deep dives allowing them to detect magnetic bands in the earth's crust, which aids long distance travel.

Though whale sharks don't have many predators, juvenile sharks can often be targeted by threats like great white sharks and orcas. Deeper dives provide them with sanctuary, as threats cannot follow, acting as an escape mechanism.

How deep is a 'deep dive'?

Whale sharks are the deepest diving marine creatures, able to survive and roam in a record breaking 1928 meters deep, recorded in the Gulf of Mexico in 2010. Or so we thought. Research recently conducted by Miller et al, drew groundbreaking conclusions that changed our entire perception of whale sharks and their marvellous abilities. Tagged in Wreck Bay, East coast Australia, 'Francky', a 7m juvenile male shark, was deployed in November of 2024. Months of being tracked indicated that this whale shark usually only went to 10-500 meters of depth, and while less frequent, occasional dives to past 1000m, with the deepest recorded at 1869m on the 16th July 2025. However, when young Francky was tracked diving to a record shattering 1978m and continuing down to a new maximum of 2527m, this not only broke the deepest dive recorded ever, but also won the whale shark species the title of deepest dwelling epipelagic fish species, and the overall deepest diver in all the ocean!

How was this carried out?

The technology developed to carry out this fascinating mission is almost as astounding as the results it raked in. Thirteen whale sharks were tagged with specialised satellite-linked tags that were attached to the dorsal fin on these giants during a series of dedicated tagging expeditions in November and December of 2024. After many test runs and failed attempts, these custom tags were developed to track whale sharks to depths no other form of technology had reached before. This was done by linking tags to a satellite that then transmitted depth and geolocation, allowing researchers to decipher the depths and locations of each tagged shark.

While this new technology was mostly effective and did its job, it was not flawless. Pressure at those depths is high and with temperatures reaching below freezing, previous attempts at trackers have been crushed under the elements. Obviously, this not-so-small hitch makes adapting technology notoriously more difficult and to accurately measure and test the true limits and potential, options become limited. However, against all odds these Argos satellite constellation tags made this experiment possible. Months and months of careful development installed these tags with an extended depth range, allowing for deep dives without arising any significant problems.

But as we know, nothing is without room for improvement. Until we figure out a way to push the pressure limits indefinitely, we cannot confidently state that 2500m is the maximum depth for a whale shark diving; how can we know if this limit is because of the natural barrier of the species or due to the depth limits on the technology we use? Well, ocean researchers asked themselves the very same thing, and as we speak, are looking for a way to defy nature's barriers and aim to improve and update data recovery, so that one day we might find the true vertical limit of these fascinating deep divers.

Why this matters for Whale Sharks

As a rapidly deteriorating species, there is so much we still do not know about the whale shark. What we do know, without a single doubt, is that the extinction of this species would be absolutely detrimental to the maintenance and balance of the ocean.

Why are whale sharks important for the ocean?

Whale sharks are apex filter feeders, meaning they feed primarily on vast quantities of plankton and fish eggs as they swim with their mouths open, filtering the water through specialised gills. These feeding patterns make sure plankton populations are kept in check, preventing any one species from throwing off the balanced ecosystem.

After feeding, whale sharks redistribute nutrients back into the sea floor through excretion, helping enrich and remineralise surface waters and promoting the growth of phytoplankton, which plays a main role in the marine food web, and in turn, supporting a range of marine life. We call this crucial process nutrient cycling, and it takes place in every functional and healthy ecosystem.

The presence of whale sharks acts as mobile nutrient distributors, as they migrate, they drag rich nutrients into poorer and more deprived areas of the ocean, helping revitalize them.

Photo by: Brendon Sing / Shark Guardian

Why are Whale sharks going extinct?

Alongside the constant human induced threats, like overfishing, tourism and habitat destruction, whale sharks are extremely vulnerable to the targeted hunting of their species. In some regions of Asia, whale sharks are hunted for their fins, meat and oil, all despite the protections and legal battles going above and beyond to make this devastating trade illegal.

Another reason why these threats are especially fatal to these creatures is actually due to their biology. Whale sharks are some of the slowest reproducing animals in nature, making population recovery extremely slow and difficult.

As always, climate change is another massive factor slowly pushing whale shark numbers into a steep decline. The rising temperatures creates the inability to roam freely in order to find suitable habitats in colder waters. Additionally, with waters getting warmer, whale sharks are driven into new habitats that, 9 times out of 10, overlap with busy shipping lanes. As collisions are becoming increasingly more common, so is the death count on these ocean travellers.

There is still so much that remains unknown to us regarding whale sharks' diving patterns, and so much more to learn and uncover. Researchers estimate that deep dives like these happen far more often than we can track or record. Understanding these patterns is absolutely critical to creating effective conservation efforts.

Next steps for Whale shark research

Defying technology barriers is the first step to being able to continue to explore and test limits. With understanding comes efficient conservation of this wonderous species. New and further developed satellite linked tags are on the horizon; ones that'll help scientists fully get insights and ideas into the undiscovered potentials and mysteries of this deep diving fish.