UC Santa Cruz Researchers Want to Use Drone Imagery to Weigh Elephant Seals

Drones are increasingly being used in the field of marine conservation. In the past, we’ve featured organizations including Ocean Alliance and Parley – both of which have used the technology to gather whale data at sea.

The Ocean Alliance team recently appeared on a BBC wildlife documentary to highlight the role of drones in their latest work.

Today we’ve learned that researchers at UC Santa Cruz, one of 10 campuses in the University of California system, have been using drones to estimate the weight of elephant seals.

The weight of elephant seals is a key metric used to determine population health and the health of the ocean ecosystem more broadly. It shows exactly how successful they have been during their seasonal hunting expeditions and gives researchers the ability to show trends and devise plans to protect the species in the long term.

Weighing elephant seals

However, weighing an elephant seal isn’t easy. It goes well beyond the awkwardness you might feel when stepping on the scales in front of your doctor. The enormous creatures, which can grow to beyond 10 feet in length, have to be sedated and manoeuvred onto a giant portable scale by a team of five or six people.

It goes without saying that it’s a delicate operation. A seal that’s not as sedated as researchers expect can be dangerous, while the risks of over-sedation are equally obvious.

Just as Ocean Alliance have pioneered the use of drones to non-invasively collect data from marine mammals, Diana Alvarado, an undergrad at UC Santa Cruz’s Costa Lab is developing a system to take the risk out of dealing with elephant seals.

The aim is simple: instead of putting people and seals at risk by manually weighing them, a drone can fly overhead and its images can be analyzed to generate accurate weight estimates.

Alvarado visited the elephant seal rookery on the beach at the Año Nuevo Natural Reserve to collect images of seals using a drone. The plan is to use image analysis software to find patterns between the drone shots and weight observations previously gathered by field researchers. Soon she hopes the program will provide reliable estimates from little more than an aerial snap.