Shark spy: bird’s eye view
Johan is pioneering a new scientific method for investigating marine animals. By flying drones above shallow coral reefs, he is hoping to find out about the abundance of sharks and rays in the area, as well as where they occur and when.
Johann Mourier
Although I was born inland, in Lyon in France, I have always been attracted to the sea and especially to sharks. This interest may be due, at least in part, to summer holidays spent every year with my family either on the Mediterranean coast in the South of France or in Brittany in the north-west, where the waters are colder but richer. As soon as I was old enough to swim, I was given a mask and snorkel to investigate what life is like underwater. Having seen my first shark in an aquarium and followed all the media programmes I...
Using drones to investigate abundance of sharks and rays in shallow water habitats
We aim to develop and adapt drones to monitor elasmobranch populations in tropical marine shallow waters, with a special focus on juvenile sharks and adult rays. We will first establish a data collection protocol and then apply it to estimating shark and ray population abundance in Moorea, French Polynesia.
Most abundance estimates of juvenile sharks in nurseries are obtained using fishing lines or gill nets, which can increase stress in new-borns and affect survival rates. Adaptation of new-generation drone technology, which is non-invasive, to monitoring of populations of juvenile sharks will not only benefit conservationists and scientists, but the animals themselves. Using a standardised protocol, data can be easily compared among nurseries, seasons and years.
Many tropical viviparous shark species give birth in specific shallow lagoon waters where their offspring will spend their first months of life protected from predators. However, these areas are generally also vulnerable to habitat degradation caused by human activities in the same locations. Because of the importance of juvenile survival to the health of populations and because of the philopatric behaviour of female sharks, protection and monitoring of juveniles and their nursery habitat is critical.
Monitoring of populations of juvenile elasmobranchs has mainly been conducted using fishing and capture-release-recapture methods, which can increase stress in new-born individuals and affect their survival rate. The rapid development, accessibility and low cost of new-generation drones mean that they are increasingly being considered for applications in ecology and conservation. Adaptation of such low-cost technology to monitoring of populations of juvenile animals as well as other biological applications will not only benefit conservationists and scientists, but the animals themselves.
The aims and objectives of this project are to:
- Establish a replicable data collection protocol adapted to shallow and clear water habitats using drones and video camera systems.
- Estimate abundance and special variations in densities of juvenile sharks and adult rays in two nursery habitats known for having different species compositions based on distance sampling methods with multiple replicates for each study location.
- Test the reliability of real-time tracking of individual sharks with drones (microhabitat use and social interactions of juvenile sharks).