For many years we have been visiting and monitoring the Blacktip Reef Shark Populations in Shark Bay, starting with the work of Shin Arunrugstichai during his time on our team. In February of 2015, we restarted that program, and have been monitoring the abundance and population dynamics of the sharks with improved techniques. During each survey, we record the position of the shark with a GPS, and also take data on the size, sex, and behavior. The idea was to look at the movement of the sharks pre- and post-spawning, with particular emphasis on the neonates or new born shark pups. What started as a weekly survey quickly turned into a few times a week, and then everyday once the spawning started. The high level of surveys meant that we were able to involve all of the interns and students within the program, and show them how to monitor these shark numbers. These surveys also gave the students an opportunity to learn how to survey and observe sharks in their natural environment, and how to identify the age and sex of the shark.
The shark surveys have been a lot of fun, and very productive. In some cases, we were recording up to 120 shark sightings in a 90 minute survey, and during post-spawning we were able to capture footage of up to 38 neonate pups swimming in the shallow waters of the bay. To make the work even more exciting, we also saw them hunting. The high volume of sharks and the shallow water meant that we were able to get close to the sharks without disturbing them.
Whilst we had a great time going out looking for the sharks, we were also faced with some difficult sights. On a number of surveys we happened across ‘ghost’ fishing nets that had drifted in to the shallow reef with the currents. Within these nets we found pups tangled and ensnared; and without being free to move around the pups had sadly died. A total of three shark pups were found dead by our team.
But, in a way, while researching the sharks we were also protecting them, as during our shark surveys we also removed many discarded nets, ropes, and other debris to prevent further entanglements. On one of the most memorable surveys, two of the surveyors came across a neonate that had been caught on a fishing line and were able to free him before any damage was caused. An exciting few moments which you can watch in the video below:
Over the course of 6 months, we recorded over 1,400 sharks. From our initial results, the best time to see adults is in mid- to late-March, and the best time to see pups in early- to mid-April. After the success of this year we are looking to continue in 2016 and will start looking at other bays around the island to identify other large resident Blacktip populations, and see if those populations follow the same patterns as in Shark Bay.
Find out more about our shark surveys, our commitment with Fin Free Thailand, or the status of the coral reef in Shark Bay.
Also learn more about sharks on our Sharks Learning Resources Page, or our Shark Fast Facts page.