Eyeing the Ocean

While diving in Belize in 1986, Greg Marshall, marine biologist and head of National Geographic Television's Special Projects Unit, had a close encounter with a shark and noticed a large remora attached to the shark's belly.
August 1, 2001

While diving in Belize in 1986, Greg Marshall, marine biologist and head of National Geographic Television’s Special Projects Unit, had a close encounter with a shark and noticed a large remora attached to the shark’s belly.

‘I thought, if we could switch that suckerfish for a video camera, what amazing things we could learn about that shark’s behavior,’ recounts Marshall, who has spent the last 15 years developing the Crittercam.

The first Crittercam was based on the sony Handicam, which hit the market in 1985. ‘We finally had systems that were fairly small, and could be made smaller by ripping them apart and reconfiguring them,’ explains Marshall. Nowadays, Crittercams are made in much the same way; camcorders are deconstructed and new computers – recording environmental data such as hydrophonic audio, depth, salinity, temperature, light levels and acceleration – are added. ‘The most significant evolution of the last 15 years is the size reduction of the Crittercam. We started with a housing system that was seven or eight inches in diameter, about 18 inches long, and about six pounds. Now it’s less than three inches in diameter, about seven inches long, about two pounds, and can reach depths up to 2,000 meters,’ says Marshall.

The technology used to attach the instrument to a critter has also undergone a significant evolution. Skin-piercing tags have been replaced by suction cups, dorsal fin clamps, epoxy patches and harnesses. Says Marshall, ‘We’re first and foremost interested in the science that we’re getting out of it, and you can only get good science if the animals are comfortable with what you’re doing.’

According to Marshall, the Crittercam appears to affect neither host animal nor the animals with whom the host interacts. The units are neutrally buoyant, meaning they don’t represent any weight to the animal. ‘In 95% to 99% of cases, there is no evidence to suggest they know it’s there. They go about doing what they naturally do,’ he says. Yet, he cites one instance (in Sea Monster: Search for the Giant Squid) in which a pod of sperm whales may have noticed the Crittercam. ‘There’s no specific evidence, but we are sensitive to that possibility,’ says Marshall.

The Crittercam has enabled about 100 marine mammal expeditions. In most cases, the species are threatened or endangered, so the Crittercam team often works with government agencies. The Hawaiian monk seal project was initiated by two scientists at the National Marine Fisheries Service in the u.s. After deploying the Crittercam on a few of the remaining 1,200 to 1,300 seals, scientists realized that the seals’ critical foraging habitat was being infringed upon by fishermen. ‘Our work contributed to the decision to protect a huge area of water that was previously unprotected,’ says Marshall.

While work with Crittercams is motivated primarily by research, doc production is also important. Says Marshall, ‘The best way to get people motivated to care about these animals is to tell their stories.’ Each year, Crittercam footage collected from about 15 research projects contributes to the production of two films, on average.

Marshall plans to continue developing the Crittercam to include features for measuring compass orientation and velocity, as well as physiological parameters like heart rate and gut content. Says Marshall, ‘Five years from now, we’ll look back on this version and say ‘What a dinosaur.’ It’ll be an inch in diameter and it will record twice or 10 times as much information.’ He also hopes to tackle more projects. ‘We learn significant new things about every animal we work with. When I think about the fact that we’ve studied 30 species, I’m impressed. But, I’m more impressed by the hundreds we haven’t studied, and all we have to learn.’

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