The Utila whale shark blog

Posted on January 28, 2008
Written by: Shark Savers

By Steve Fox

January 28, 2008

Everyone can make a difference. For most of my life, I lived and worked in London England and had a normal job. My vacations were centered on scuba diving, a pastime I had enjoyed for many years.

Some people called it a mid-life crisis (even though I was much too young to have a mid-life crisis!!!!!). Some called itchy feet. I did not know what it was. All I knew was that there was more to life than what I was doing. A change had to be made.

Whale Shark
Whale Shark

In 2001 I moved to Utila, Bay Islands, Honduras and opened a dive shop and resort. The big attraction of this area for me was the Whale Sharks. They had been a fascination of mine for years and I wanted to be able to work with them and help with conservation issues.

After diving on Utila and swimming with countless Whale Sharks I noticed that there was a flaw with the tagging system that was being used. There was just one person that was doing any work with the Whale Sharks in the area and they were doing it for just one week a year. The main method they were using was visual ID tags. These tags are attached to the Whale Shark and they have a number on them. When this Whale Shark is seen again the person reports the number to the organization that tagged it and this will provide a record of where the Whale Sharks were traveling.

Whale Shark tag
Whale Shark tag from

The problem was that when we saw Whale Sharks that had been tagged with these visual ID tags they were often unreadable. They had either been broken or bitten off or were so encrusted with algae that we could not see the numbers. Therefore, we had no way of tracking the Whale Sharks and finding out who had tagged them. The whole idea needed a rethink.

I spent many weeks searching for a different system and finally found At that time the system had only been used in Australia. I contacted Brad Norman who started Ecocean and asked if we could use their system. This was the start of Ecocean were totally behind us and gave us every piece of support needed.

The incredible aspect about the system is that anyone can use it. You do not have to be a researcher. Anyone-- diver, snorkler or just a swimmer--that has a camera can take a photo of a Whale Shark and send it to Ecocean to record a sighting of a Whale Shark. This was another great plus. It was able to use the resources of anyone that went into the water with a camera and saw a Whale Shark, not just relying on researchers. The public is as important as any researcher to Ecocean.

Whale Shark spot pattern
Whale Shark spot pattern

Anyone who sends a photo of aWhale Shark to Ecocean will instantly get an email thanking them for their submission. It will then be decided if a spot pattern can be identified from the photo. Ecocean found out that behind the gills the spots on the Whale Shark are unique to the individual, much like a fingerprint. If a pattern can be identified and the Whale Shark has been seen before you will be informed of its history and movements. If it has not been seen beforeyou will be informed of that this is a new Whale Shark. If it is ever seen again you will receive an email telling you.

The system was devised by 3 people: Brad Norman, a Marine Biologist, Jason Holmberg, a computer expert, and Zaven Arzoumanian, who works for NASA. They used a system that was designed to recognize stars in the night sky for the Hubble telescope (white dots on a dark background).

As of today, there are 1093 recognized Whale Sharks and 4172 encounters from 37 countries in the Ecocean database. This is a terrific acheivement.

On Utila I have been working hard to get all the dive companies involved in this project and we are beginning to make some headway.

During 2007, with the help of people working in other countries, we were part of tracking a Whale Shark through three countries in one year: Honduras, Belize and Mexico. This is the first time it has ever been done using this method.

Also in conjunction with the above project, we are working with Dr. Rachel Graham of Belize who is setting up the largest acoustic array for Whale Sharks that has ever been implemented. The project is called Marine Meganet. There are underwater receivers in the Flower Gardens off the coast of Texas, Mexico, Belize, Honduras, and hopefully soon in Cuba.

A small acoustic transmitter is attached to the Whale Shark and when it passes a receiver it sends a signal and we know that it has passed. This will give us a huge amount of information about the Whale Shark movements in the Caribbean and Gulf of Mexico.

The other luxury of this system is it can be used with other species at the same time as the receivers will pick up signals from any acoustic receiver that is attached to any species.

What we have now implemented in Utila is a year round project on Whale Sharks. Even though March, April and September do seem to be the busiest times for Whale Sharks, we have records through Ecocean showing that we have seen a Whale Shark in every month of the year. There is nowhere else in the world that this is known to be the case. We are very lucky.

This year we have a great new member of staff, Isabelle Foisy. She is a French Canadian dive instructor who has returned to Utila especially to work with the Whale Sharks and She will be writing regular updates to this Shark Savers blog on what we are seeing and what is happening on Utila.