LIMA, Peru - Peruvian authorities say at least 50 sea lions have been intentionally poisoned with fish laced with insecticides since mid-January off a single beach.

The Production Ministry said Thursday that lab testing confirmed the poisoning. The ministry oversees Peru's fishing industry and its ocean institute IMARPE examined the sea lion corpses, which were found on Bodegones beach in the northern state of Lambayeque beginning Jan. 13.

The ministry says it has asked Peru's environmental investigations agency to look into the killings.

Carlos Yaipen of the nonprofit ORCA conservation group blames the problem on the government, saying official negligence allows unscrupulous fishermen to kill marine animals they perceive as competitors.

Yaipen cited as one example the November 2009 killing of 350 sea lions off Colan beach in the northern region of Piura.