Locally known as Sili or Sili Sili, the Giant mottled eel (Anguilla marmorata) thrives in Bago River and it can be found on shallow waters of the river sides, mudflats, mangrove areas and sometimes in rice paddies nearby rivers.
This species can be distinguished from other eels by its mottled coloration, arrangement of teeth and the long dorsal fin. The teeth in both jaws are arranged in two or three rows. One row consists of distinctly enlarged teeth that often form a cutting edge. The inner row comprises smaller teeth that are usually separated from the cutting row by a narrow toothless groove. The adult eels are yellow with a greenish brown to black marbling on their back and a white belly. The young eels have less visible marbling and are grayish to yellow. The giant mottled eel is cylindrical with small, well-developed pectoral fins and a protruding lower jaw.
Traditional eel fishing is carried out using tools such as weaved bamboo traps: these are left on shallow riversides where eels are spotted, leaving them there for an hour or two, and later checking the trap for some catch. Once caught, the eel is prepared for consumption or sold at the market. It is thoroughly cleaned with wood ash; the technique for getting rid of its slime is to rub it with young guava leaves, ash, salt and papaya leaves.
Sili is a staple food for the Bagonhons (inhabitants from Bago) and it is cooked grilled or used to prepare adobo, inasal, paksiw sa gata and other traditional recipes. It is also marinated with salt, garlic, vinegar or sun dried and fried.
In the past few years there has been a decline in the eel population due to its popularity. In 2006 one Resident of Barangay Tabunan in Bago City, collected river Eels to breed and farm. It was a success through his own research on Eel Farming. In the same year, a strong typhoon caused a flood in their area, and his tanks overflowed, and eels swam everywhere.