For the past month alone, Alvarez said the PCG caught five foreign vessels poaching tuna and other products on Philippine waters.
"It is the frequency of the intrusion, even counting only those apprehended, that alarms us," Alvarez said.
He said the 38 Taiwanese, Chinese and Indonesian crewmen who were apprehended on the five vessels were even carrying fake working permits and fake boat registration papers.
According to PCG intelligence officials, this indicated that these foreign fishermen had links with the government agencies that issue these documents.
But the Maritime Industry Authority (Marina), which issues boat registration papers, Bureau of Fisheries and Aquatic Resources (BFAR), which issues fishing permits, and the Bureau of Immigration, which issues working permits to aliens, have denied issuing the papers found in the crewmens possession.
Alvarez also ordered the PCG to find the foreign fishermens local cohorts and charge them along with the crewmen.
"The foreigners are not in a position to possess the fake working permits and fake boat registration documents unless someone in the country provided them with those spurious documents," Alvarez said.
The fishing boats M/V Fly Young 16, M/V Gozel 2, M/V Sunny 2, M/V Aneka 218 and M/V Royal San, which were caught in different places off Luzon and Palawan, are now in PCG custody and subject to forfeiture proceedings.
The boats are apparently Taiwanese boats, PCG officials said, but they did not carry Taiwanese registration papers but only the fake Marina registration documents.
Charges of illegal fishing, forgery and falsification of public documents have been filed against the boats crewmen who are detained at the Veterans Anchorage in Aparri, Cagayan.
The authorities said one of the boats, the Royal San, was apparently an Indonesian boat masquerading as a Taiwanese fishing vessel with fake Philippine boat registration documents.
PCG men who apprehended the crewmen and seized the Royal San said the crewmen were detaching the name Kmna Tuna Lestari 8 from the port and starboard side of the pilothouse when they were accosted off Sabtang Island in Palawan on May 1.
Two weeks earlier, the PCG caught the Fly Young 16 and the Gozel 2 off Santa Ana town in Cagayan province on April 16. The boats 13-man crew carried fake working permits.
On April 29, the PCG caught the Aneka 218 off Poro Point in La Union. The circumstances of the apprehension of the Sunny 2, however, remained unclear.
Alvarez said the authorities should guard against intrusions of this kind because such vessels may also be used by criminal syndicates to sneak in undesirable foreigners into the country.