By Clare Simm
Following the global media interest in the international fishing fleets on the outskirts of the Galapagos Marine Reserve, and the news that Hope the whale shark went missing in May, this August’s Galapagos Whale Shark Project (GWSP) field research trip was more important than ever.
We still know relatively little about the movements of these giant ocean travellers, which are listed as Endangered on the IUCN Red List, including where they go to give birth. Despite their protected status, they are under threat from industrial fishing which either catch the sharks as bycatch or target them for their fins.
The expedition, consisting of scientists and technicians from the GWSP, University San Francisco Quito and the Galapagos National Park, focused on tagging whale sharks at Darwin’s Arch, in the north of the Galapagos Marine Reserve, as well as trying to determine their reproductive states and health in general. Gathering this information will allow us to continue to build up a picture of the lives of whale sharks and allow better management measures to be established for these threatened creatures.
During this year’s expedition, the team managed to tag ten whale sharks – nine adult female and one juvenile male – using SPLASH10 satellite tags. These tags track the vertical and horizontal movements of the sharks, recording depth, temperature and light. The tag transmits this data, together with its GPS position, when the animal exposes the tag above the surface of the water. The GWSP team will analyse the underwater data which should give us an amazing 4D account of the sharks’ movements. Once combined with the underwater geology, we should be able to see what environmental cues and habitats the sharks use. This could be a major breakthrough to better understanding their movements and requirements, allowing us to improve their protection.
In addition, the team managed to take four blood samples from two adult females which should help to establish a baseline for their health. They also identified 25 new individual whale sharks through photo-identification. Each shark has a unique pattern of spots behind their gills which act like a fingerprint. These photos were uploaded to the Wildbook for Whale Sharks, which is a global database of whale sharks and used by marine biologists to learn more about whale shark aggregations and where they migrate.
First evidence of whale shark migration between Galapagos and Cocos Island
Within days of the expedition, several of the tagged whale sharks entered the swimway between the Galapagos Marine Reserve and Cocos Island National Park, Costa Rica. This area, of around 120,000 sq. km follows the Cocos Ridge – an underwater mountain range linking the two reserves – and was recently declared a Mission Blue Hope Spot. Many species of endangered sharks and turtles migrate along this swimway to reproduce and forage. Worryingly, the area also attracts large international industrial fishing fleets, so we have been supporting the collection of evidence needed to protect the swimway.
Excitingly, we are now one step closer. One of the female whale sharks (#203641), named Coco, travelled along this swimway after being tagged, arriving at Cocos Island on 5 September. This is the first ever confirmed migration of a whale shark between the two protected areas!
This journey demonstrates the importance of protecting this swimway from industrial fishing fleets, helping to conserve countless endangered migratory species on their journeys, and there is hope that the governments of Ecuador and Costa Rica will work together to make this a reality.
Ways to get involved
We are supporting the collection of evidence to make the Galapagos-Cocos Swimway a reality through our Endangered Sharks of Galapagos Programme. Please help us protect endangered whale sharks and other threatened migratory species by donating today.