Sightings, tech help track ocean giant

BREST, France - The sight of a basking shark's brooding silhouette gliding through the waters off western France is more than just a rare treat for sailors - it is a boon for scientists trying to trace its secretive migrations across the globe.

It may be the world's second largest fish, growing to more than 10 meters, but the basking shark, or Cetorhinus maximus, is an enigma for scientists eager to help preserve the plankton-eating giant after centuries of overfishing.

Hunted voraciously for its massive fin, as well as its oily liver and meat, global populations of basking shark declined precipitously during the 20th century. The species has struggled to recover because of slow reproduction rates.