Galapagos Whale Shark Project: brief history…
In the late 1980´s very little diving was being done at the northern most islands of Wolf and Darwin in the Galapagos Archipelago. At the most one dive boat a month, might have been found in these waters.
Occasional small fishing vessels from the Galapagos that were catching grouper, snapper and Jew fish, as well as lobster fisherman also plied these waters. Perhaps more frequent were the long-line vessels of differing nationality whose main target were the principal shark species that are found in considerable numbers throughout this area.
Within the dive community of the Galapagos we were aware that the whale shark, Rhincodon typus, had been observed in the area, but very little was known about frequency, distribution or seasonal activity. Local fishermen spoke of the huge ¨pez gato¨ a strange white poker dotted animal that they had often just beneath the surface mostly at Wolf & Darwin.
My first whale shark sighting was in 1990 at the Arch of Darwin. As we began slowly to recognise swimming patterns and some of their behaviour, we spotted them with increasing frequency. In those early years we assumed that the larger animals were males, but when I actually began checking for sex realised that none of the whale sharks were male and 20 years later I have only positively identified females.
Another factor I noticed was that certain individuals had scarring either from encounters with predators such as Orca whales, or perhaps sea going vessels. Furthermore these distinguishing marks could be used as a basis for identification of individuals in order to study a little more in detail ¨our¨ Galapagos whale shark population.
To this end, in 1999, I devised a simple one page multiple question survey sheet which was distributed amongst a number of the dive boats to be filled in by the on board dive masters and returned to me. With the results from a fairly small number of surveys returned as well as my own observations during hundreds of hours logged underwater at Wolf and Darwin, certain patterns became discernable.
It seems that the whale sharks are observed in every month of the year, but with considerable peaks in the frequency of sighting between the months of June to November, which corresponds with the cool ¨garua¨ season in the Galapagos when the Humboldt and Cromwell currents are most prolific. Furthermore it became apparent that individuals were spending relatively little time in the waters around Wolf and Darwin as rarely were the same individuals seen repeatedly from one week to the next, (pers. Ob. during weekly dive trips to the northern islands). In terms of behavioural observations it was clear that these animals are not actively feeding in this area, which has a paucity of plankton in comparison with the rest of the Archipelago.
Repeated sightings occurred. For example one individual with multiple bites out of the tail, making her easily distinguishable, I first saw at Wolf Island on October 18th 2000. I saw her again at the Arch of Darwin Island on two occasions, 5th December 2001 and again on the 28th October 2002. Despite the fact that I have dived these waters at the same time of year every year until now, I have not seen this particular whale shark since.
The more I began to learn about this species the more I realised that we know virtually nothing about the natural history of the species worldwide. Many questions are still unanswered using these visual survey techniques.
To this end I proposed a project to begin tagging a number of individuals to discover not only their movements in and around the Galapagos Marine Reserve, but also their migratory routes worldwide.
If our local population is comprised only of females, where are the males? They could be to the south of the Archipelago feeding in the plankton rich waters of coastal Peru or even Chile.
Why do the females congregate at Wolf and Darwin? The only feasible reason would be for birthing as these sharks are ovoviviparous, giving birth to live young. What happens then to these young animals as they are though to be born about 80cm – 1m long and are never seen in the Islands?
Why do they fluctuate in numbers so much around the full moon? Are they birthing at depth during this phase of the moon?
Do the Galapagos sharks travel the world’s oceans? Are these individuals being sighted of Africa, or Ningaloo Reef off Australia? Only satellite tracking and DNA studies will provide the full answers to these and so many other questions. This may give us a fuller understanding of the complexities of the life of a Whale Shark, and only then can we afford them protection at a worldwide level.
How can it be that still today we know nothing about this huge prehistoric animal and yet we are harvesting them at a commercial and industrial level? This species could provide a real life ¨Jurassic Park¨ study case.
The Galapagos Whale Shark project, which will combine the efforts of the Galapagos National Park Service, the University of Davis, California, Conservation International and the Charles Darwin Research Station, has been devised and developed to answer these questions using all available, affordable technology. We also hope in further stages to continue work using submersibles and / or submarines, ultra light or small aircraft for aerial surveys. Underwater video will also be used to document the project for educational and outreach purposes and with a view to producing a commercial documentary for future funding. For more details please see adjoined documents or contact us at: