Conserving ocean wildlife in the big blue

Ocean biodiversity is in decline. The iconic scalloped hammerhead shark, for instance, has recently been listed as Critically Endangered by the IUCN. With similar declines occurring across a wide range of species, concern is mounting over ocean health and seafood security.

Large marine protected areas (MPAs) are increasingly being established to halt and reverse declines in ocean biodiversity. Large MPAs pose particular challenges relative to their coastal cousins such as Australia’s Great Barrier
Reef Marine Park. Large MPAs encompass vast tracts of open ocean, a habitat that covers 75% of the Earth’s surface. We know relatively little about open ocean wildlife, with many species with a low and patchy distribution, which makes them difficult to observe and study. Understanding how these animals use space is fundamental to their

Ocean wildlife is at risk and thus sampling methods must be non-destructive so scientists are not required to kill animals to learn about them. Baited remote underwater video systems, or BRUVS, were originally designed in 1975 to study reef fish and are now used globally. Building on the experience of seabed BRUVS, the Marine Futures Lab at the University of Western Australia developed a mid-water drifting stereo-BRUVS to study the open-ocean wildlife that lives in the water column.

A BRUVS rig deployed during an expedition to Rapa Iti in French Polynesia. © Manu San Felix

Mid-water stereo-BRUVS consist of two GoPro cameras mounted on a stainless-steel frame rig, angled towards a steel arm with a bait canister on its end. They are deployed from a boat in a “long-line” formation of five stereo rigs. Suspended at 10 metres below the surface, they drift untethered for two hours, recording animals that swim through the field of view. A typical day has team members deploying and recovering the lines four times to generate 20 samples per day. Back in the lab, video footage is manually analysed to identify, count, and measure each observed individual.

Since their development in 2012, the team at the Marine Futures Lab has successfully completed over 60 expeditions at 35 locations around the world, in which we have counted more than 100,000 individuals from over 250 species. This methodology has been used to monitor fish and shark pelagic communities within MPAs globally, creating baselines against which the benefits of MPAs can be determined.

In Galapagos, in collaboration with Dr. Alex Hearn from the University of San Francisco de Quito, with support from GCT and the Prince Albert II of Monaco Foundation, we are using mid-water BRUVS to understand how ocean wildlife uses the big blue around islets and seamounts.

The use of mid-water BRUVS has revolutionised research in the open ocean.

A key next step lies in technology transfer whereby mid-water stereo-BRUVS are adopted in locations where there is a need to better understand ocean wildlife and the benefits of MPAs. Adoption of this cheap and easy
technology in areas with or considering large MPAs will unveil ocean wildlife status and will also help coastal communities better understand the state of their ocean wildlife.

The development of artificial intelligence for automated identification, counting and measurement is also key given the large amount of collected video and the many hours that manual processing requires.

The Marine Futures Lab is collaborating with different stakeholders to develop open-source software for video processing, which will allow us to keep counting fish in this habitat and contribute the knowledge needed to build resilient oceans in which wildlife flourishes.

Written by: Naima López, PhD student. Naima is a marine biologist from Spain. Always captivated by marine predators she joined the Marine Futures Lab at the University of Western Australia in 2019 to start her PhD studying ecology of highly migratory oceanic sharks and better ways to protect these species.

This article originally featured in the Spring-Summer 2020 issue of Galapagos Matters

What can you do to help?

Please help us conserve the endangered sharks of Galapagos today by giving a donationadopting a hammerhead shark or joining up as a GCT member.