Leopard sharks (also called Zebra Sharks) are a unique species of sharks with beautiful stripped (juveniles) or spotted (adults) patterns on their skin, and a body which can reach about 2.5 meters in length. They tend to be timid and slow moving, are nocturnal hunters, and spend most of the day sleeping. This means that they are often spotted by divers, and are safe to approach and experience up close. These traits make the leopard shark a favorite sighting by divers and snorkelers, and also allows for unique ‘citizen science’ based opportunities for divers to contribute to their research.
One group working to utilize this opportunity is Spot the Leopard Shark, a community based monitoring program started by Dr. Christine Dudgeon from the University of Queensland. This monitoring program allows divers to record their Leopard Shark observations into the Spot the Leopard Shark facebook page, where the individual shark can then be identified using the pattern of its spots. Divers just need to photograph the left side of the shark, so that the spots may be mapped. If the leopard shark has been seen before, then this data can be useful in estimating population sizes, identifying important habitats and nursery areas, and learning about the animal’s life cycle. If the individual has not been seen before, then you get to name it. To date, the project has identified over 327 individuals in Australia, and over 160 in Thailand, spanning over 8 years of photographs for at least 1 individual.
Unlike many coral reef animals that we currently research at the NHRCP, sharks are difficult to study due to their large home range sizes, and low relative abundance. Shark surveys can often be expensive and time consuming, with many of the dives not finding any sharks at all. Just like researching seahorses or sea turtles, it takes a large distributed network of researchers to get the ecological and biological data necessary to properly assess their populations and manage policy or trade. And, just like the iSeahorse.org database, divers can fill that gap and be the network of eyes and ears that researchers need.
There are many ways for you to help contribute to global shark databases as a diver, such as through Spot the Leopard Shark, Whaleshark.org, or the e-shark project. Take a moment to log any of your sightings to those databases, and not only will you be helping their research, you will also be able to track the shark you saw over coming years through other diver’s observations. Even if you haven’t seen sharks, you can still contribute to the data, because it is also very important for them to know where you have dived and did not see a shark.
DID YOU KNOW?
The Leopard Shark (Stegostoma fasciatum) is listed as vulnerable by the IUCN Red List of Threatened Species. According to the IUCN report, there is limited data on their population levels or decline, except in the Gulf of Thailand.
Locals here on Koh Tao report that Leopard sharks used to present around our island, but have since disappeared from the Gulf. The leading causes for this disappearance are thought to be over-fishing/destructive fishing and pollution.