Using drifting cameras to monitor marine reserves

Cover image

Blue shark (Prionace glauca) filmed in the Perth submarine canyon using a novel generation of drifting baited cameras.

Photo: Centre for Marine Futures.

Comparative assessment of pelagic sampling methods used in marine monitoring

There is an urgent need to synthesise and compare pelagic sampling methods to determine how ...read more

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SAMPLING THE BIG BLUE

Study sites within the Perth Canyon Commonwealth Marine Reserve (CMR) are shown as yellow squares and lines represent the trajectories of individual camera units. The locations of wildlife sightings (based upon times of first detection) for identified species are shown as black circles. The boundaries of the eastern park appear as a dark outline.

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BAITED CAMERAS

Schematic diagram of a drifting stereo-BRUVS in deployment.

CITATION

Bouchet PJ, Meeuwig JJ. 2015. Drifting baited stereo-videography: A novel sampling tool for surveying pelagic wildlife in offshore marine reserves. Ecosphere, 6: art137.

HIGHLIGHTS

• A vast portion of the world’s oceans remain virtually unexplored, in part because of technological challenges associated with sampling deep waters and topographically complex areas.

• The Perth submarine canyon (approx. 30 km west of Rottnest Island in Western Australia) is an example of a prominent and ecologically important seabed structure that has received little research attention to date.

• We developed a novel digital video sampling system appropriate for use in offshore environments over rugged terrain, and tested it in the smaller of the Perth Canyon marine national parks (as per 2013 Commonwealth marine reserve designations).

• We used the video footage as a basis for constructing models of the distribution of pelagic fishes and sharks that can inform future management.

• Results indicate that the park may not capture the most suitable habitats for pelagic wildlife.

SUMMARY

The Perth submarine canyon, situated approximately 30 km west of Rottnest Island in Western Australia, has been listed as a key ecological feature by the Australian Government, and is one of the most prominent topographic structures on the country’s continental shelf. Similar in size to the Grand Canyon in Arizona (USA), it is known to influence regional patterns of marine productivity and ocean current circulation, to support seasonal aggregations of endangered or threatened megafauna including humpback, sperm and pygmy blue whales, and to be a hotspot for large migratory fish species such as tunas, kingfish and billfishes. Despite this important role and rapidly increasing pressures from military exercises, shipping traffic, waste disposal and recreational/commercial fishing, it is an area that has to date received surprisingly little research attention. In 2013, the declaration of the Australian representative network of Commonwealth Marine Reserves (CMR) saw the establishment of a marine national park at the head of the canyon system. Appropriate data on wildlife dynamics and distribution are essential in maximising the conservation success of the park and guiding its effective management. This work aimed to document the behaviour, relative abundance and species richness of oceanic fishes and sharks at the head of the canyon to provide the baseline information needed for the long-term monitoring of marine predators in the region.Baited stereo-videography is a perfect candidate for this but existing camera systems prove inadequate for deployment in canyon habitats, which are often too deep and with incredibly rugged terrain. A key goal was therefore to develop an appropriate tool for tracking elusive animals in topographically complex habitats. We created a novel system of drifting pelagic baited stereo-video cameras which can operate in these difficult conditions. The instruments are portable, semi-autonomous and inexpensive, allowing the recording of high-quality, high-definition video footage in near-real time and over broad stretches of ocean space.

ABSTRACT

We present a novel system of drifting pelagic baited stereo-video cameras that operate in deep-water, topographically complex environments typically considered inaccessible for sampling. The instruments are portable, semi-autonomous and inexpensive, allowing the recording of high-definition video footage in near-real time and over broad stretches of ocean space. We illustrate their benefits and potential as non-extractive monitoring tools for offshore marine reserves with a pilot study conducted within the newly established Perth Canyon Commonwealth Marine Reserve, southwestern Australia (32° S, 115° E). Using occupancy and maximum entropy models, we predict the distribution of midwater fishes and sharks and show that their most suitable habitat encompasses a wider fraction of the canyon head than is covered by park boundaries. Our proof-of-concept study demonstrates that drifting pelagic stereo-video cameras can serve as appropriate field platforms for the construction of species distribution models with implications for ocean zoning and conservation planning efforts.

FUNDING & ACKNOWLEDGEMENTS

We are grateful to Lloyd Groves, John Harwood and Sébastien Agulhon for their assistance with field work and data management. We thank Jan Hemmi for developing the MATLAB algorithm used to process the video footage. This research formed part of a PhD thesis undertaken at the University of Western Australia and supported by both the Margaret Middleton Fund for endangered Australian native vertebrate animals (Australian Academy of Science) and the Marine Biodiversity Hub, a collaborative partnership from the Australian Government’s National Environmental Program (NERP). The first author was the recipient of a scholarship for international research fees (SIRF) during the course of this work.