Piracy charges against 30 people who were aboard a Greenpeace ship protesting Arctic drilling have been reduced by Russian authorities to hooliganism, the head of the Investigative Committee announced Wednesday.

The Russian coast guard seized the Arctic Sunrise after two activists attempted to climb onto an oil rig in the Pechora Sea on Sept. 19. Investigators charged all of those on board with piracy — which carries a 15-year sentence — and the courts refused to grant bail. Hooliganism carries a maximum sentence of seven years, although conviction usually brings much milder punishment.