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 gata¨ a strange and terrifying white poker-dotted animal that they had often seen 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 nearly three decades later have only positively identified four males. The remainder of the sightings, a massive 99.8% are female.
We began simply recording sightings, behaviour and distinguishing marks on a check sheet. 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, not only locally and regionally but also worldwide.
To this end I proposed a project to begin tagging a number of individuals to investigate not only their movements in and around the Galapagos Marine Reserve, but around the Eastern Pacific and further. The project included a number of institutions and was aimed at gathering as much information about these sharks as possible on dedicated field trips to Darwin Island.
Our goal, to answer a number of basic questions that are part of the mystery that surrounds this species…
If our local population is comprised only of females, where are the males? Are they elsewhere in the Galapagos or further south off the coastal waters of Peru?
Why do the females congregate at Wolf and Darwin? Given they all appear to be in an advanced stage of pregnancy are they birthing in this area?
If the neonates are around 60-80cm in length at birth, (as whale sharks are ovoviviparous and give birth to live young), why are we not seeing newborn sharks as well as adults. Where might they live the first years of their lives?
Do the Galapagos sharks travel the world’s oceans? Are these individuals being sighted around Africa, Indonesia or off Australia? Only satellite tracking and DNA studies may provide the full answers to these and so many other questions and give us a fuller understanding of the complexities of the natural history of a Whale Shark.
How can it be that still today we know relatively 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, as whale sharks are in reality dinosaurs that have survived a bygone era.
The Galapagos Whale Shark Project, combining the efforts of all our partners through a multi disciplinary study, began to gather the data necessary to better understand whale sharks. Through this understanding we hope create awareness and the foundations necessary for their protection and conservation.
Jonathan R. Green
You would like to READ MORE about the project?
Go BACK to