Wave Glider ocean robots to track sharks in northern California

If you’ve ever sat in a beach-side coffee house wondered if there was a white shark in the vicinity, then wonder no more because now there’s an app for that. A team of Stanford University researchers lead by Prof. Barbara Block is deploying a fleet of static buoys and Wave Glider robots to turn the waters off the coast of San Francisco into a huge Wi-Fi network to track tagged fish and animals. This will allow scientists to better understand sea life movements, but the project also includes offering a free app to the public that will allow them to track northern California white sharks on their tablets and smartphones.

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Tracking sea life can be something of a hit and miss affair. On one end of the spectrum, you can tag fish and hope to figure out how they migrate by plotting when and where someone later catches them. At the other end, you can use sophisticated tags that act as radio beacons that satellites can pick up. Both methods work, yet both lack the desired degree of detail or comprehensiveness. The Stanford team plans to bridge this gap by establishing a network of static and mobile data receivers off the coast of northern California between Monterey Bay and Tomales Point. This network will collect data from tagged sharks, tunas, whales, seals, seabirds and turtles that will be used to correlate twelve years of satellite data.

The network acts like a huge Wi-Fi system and relies on cheap, long-lasting acoustical tags. When a tagged fish passed within 1,000 feet (304.8 m) of a data receiver, the acoustic signal is recorded and uploaded along with a timestamp and GPS location to a shore station. The buoys that make up the static part of the network are placed where white sharks are most likely to be. However, it's an axiom of science that if you already know where something is, then there’s no point in looking for it, so the network also uses Wave Glider robots to rove about the area to cover any holes.

The solar and wave-powered Wave Glider is an autonomous ocean-going robot built by Liquid Robotics of Sunnyvale, California. It made headlines last March when it broke endurance records by traveling unaided from San Francisco to Hawaii. The 208 x 60 cm (82 x 24 in) machine is solar powered and uses wave power by means of a submerged “glider” to steer and move forward. With an average speed of only about two knots (2.3 mph, 3.7 km/h), this energy-efficient design may not win any races, but is acoustically quiet and gives the Wave Rider exceptional endurance with mission durations already clocked at over 400 days. This makes it ideal for cruising about looking for errant sharks and other tagged sea life.