Oct. 10 (UPI) -- The presence of a large Chinese fishing fleet off northern Chile has raised concerns among small-scale fishermen and maritime authorities amid suspicions of illegal fishing and the depletion of Humboldt squid -- one of the most valuable resources for small-scale fisheries in the region.

The Chinese vessels are said to be operating just a few miles from the boundary of Chile's Exclusive Economic Zone. Their presence has caused a sharp drop in catches in recent months, local fishermen say.

"We haven't seen any Humboldt squid for three months. These ships are like termites in the ecosystem," a leader of the Iquique Fishermen's Federation said in an interview with Radio Biobío. He added that the Chinese boats appear to be disrupting the natural migration of the species toward the coast.

According to a report from the Chilean Navy, about 66 vessels have been detected off Iquique and more than 160 in transit between Arica and the northern border, all operating outside Chile's 200-nautical-mile exclusive limit.

Rear Adm. Sigfrido Ramírez, director of Maritime Safety and Operations, said the Maritime Authority carries out constant monitoring through satellite, aerial and surface means, adding. "No fishing activity has been confirmed within Chile's Exclusive Economic Zone."